Calvarial Lesions: Overview of Imaging Features and Neurosurgical Management

Calvarial Lesions: Overview of Imaging Features and Neurosurgical Management | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Original Article Calvarial Lesions: Overview of Imaging Features and Neurosurgical Management Isabella Nasi-Kordhishti, Johann-Martin Hempel, Florian Heinrich Ebner, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-161395/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Mar, 2021 Read the published version in Neurosurgical Review → Version 1 posted 2 You are reading this latest preprint version Abstract Objective Calvarial lesions are rare and can present as a variety of different diseases. The lesions can be palpable on the skin, cause local pain and paraesthesia and, depending on the location, neurological deficits can also occur. This research aims to present an overview of typical imaging features as well as neurosurgical management. Methods We examined the charts of patients who underwent surgery on a calvarial lesion in our department between 2004 and 2017 (n=133). Retrospectively, the pre-, intra- and postoperative data were analyzed with morphological and histological findings and compared with each other. Results Pain, swelling, cosmetically disturbing and neurological deficits were the main complaints. Seventy-seven lesions were limited to the bone, while another 56 lesions showed an infiltrating growth in the adjacent tissue. Depending on the clinical signs and suspected diagnosis, a biopsy, a partial removal or a complete resection was performed. Histiocytosis (n=20), meningiomas (n=20), metastases (n=19) and osteomas (n=16) were the most common lesions. Fibrous dysplasia (n=6) and intraosseous hemangioma (n=9) were less common; other lesions were present only in isolated cases. Conclusion Imaging gives a hint, but the diagnosis can be only confirmed by histological examination. The surgical strategy depends on the complaints, location of the lesion and suspected diagnosis. Adjuvant treatment should be initiated according to the histological findings. Neurosurgery Calvarial lesions imaging histiocytosis meningiomas metastases Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Intraosseous lesions of the calvarium are often slow, progressive processes that manifested in swelling, local pain or sensitivity disorders. Asymptomatic processes are often described as random findings in the imaging. A variety of diseases can hide behind such a lesion. We distinguish between lesions that originate primarily from the bone and those that present a secondary bone infiltration. Depending on the author, the first category is divided into three or four subcategories: primary neoplasia (in individual papers already divided into good and malignant primary neoplasia), secondary neoplasia and tumor-like lesions [ 17 , 22 ]. Using adequate imaging as computed tomography (CT) and magnetic resonance imaging (MRI), suspicions can be drawn about the dignity of the present lesion, especially if the clinical symptoms and the case history of the patients are included [ 8 , 14 , 12 ]. A definitive statement about the dignity of a lesion can only be obtained by histopathological examination. The clinical management methods of calvarial lesions differ greatly depending on the underlying entity [ 17 ]. Most benign lesions, such as osteomas, meningiomas or intraosseous hemangiomas, can usually be completely resected and do not need further treatment [ 16 , 23 , 18 , 5 ]. However, malignant lesions, such as metastasis or osteolysis in plasmacytoma, potentially require an adjuvant therapy such as chemotherapy, immunotherapy or radiation [ 3 , 17 ]. Rare diseases such as histiocytosis require individual diagnostic and therapeutic evaluations [ 2 , 20 ]. Since calvarial lesions are rare diseases in neurosurgery, only a few single case reports and reviews have been published. This research aims to present an overview of calvarial lesions based on typical imaging features and the histopathological results, as well as the neurosurgical management. Materials And Methods Included are all children and adults with lesion of the clavarium and orbita who were operated in our department between 2004 and 2017. The pre-, intra- and postoperative data, as well as the imaging and histopathological findings, have been analyzed retrospectively. All patients with solitary lesions at the skull base were excluded. Since this is a surgical series, patients who have been treated only conservatively are not included. This case series does not claim to be a presentation of all possible disease entities. All statistical tests were performed using JMP 13 (SAS Institute Inc., Cary, NC). Descriptive data are shown as mean, standard deviation (SD) and percentage. Results - Pre- and intraoperative evaluation A total of 133 patients were operated, 74 of whom were women and 59 were men. The age distribution of 0–95 years is homogeneously distributed over all decades with a mean of 42 years and a standard deviation (SD) of 24.7 (Fig. 1 a). The patients’ main complaints (Fig. 1 b) were swelling (n = 91; 68%), pain (n = 61; 46%), and subjective cosmetic impairment (n = 58; 44%). Rarely represented were focal neurological deficits (FND) (N = 22; 17%), feelings of tension of the skin (n = 21; 16%), exophthalmos (n = 8; 6%), diplopia (n = 7; 5%), and dents in the skin (n = 4; 3%). Only 23 patients have not complained of any symptoms. The location of the lesions is distributed in every part of the skull with a clear frontal prevalence (n = 55; 41%). Parietal (n = 26; 19%), occipital (n = 20; 15%), orbital (n = 12; 9%), sutural (n = 7; 5%) and temporal (n = 4; 3%) lesions are rarer. In two newborns, a lesion was found directly on the fontanel (1.5%). All patients, except the two newborns, have received preoperative cranial imaging using CT and MRI with and without contrast enhancement. The newborns were dispensed with CT diagnostics. Also, an X-ray, sonography, PET-CT or bone scintigraphy was performed preoperatively in individual cases. The typical findings for the lesions are described in Table 1 after the classification of the postoperatively obtained histology. Table 1 Imaging and intraoperative macroscopically findings of calvarial lesions after histological diagnosis. CFD: color flow doppler sonography; CNS: central nervous system; CSF: cerebrospinal fluid; CT: Computed tomography; MRI: magnetic resonance imaging; PET: Positron-Emission-Tomography. Tomography findings CT and MRI Other imaging methods Macroscopically intraoperative Primary neoplasia Arachnoidal cyst (n = 1; 0,75%) - Calvarial (Tabula interna and externa) thinning - Well circumscribed cyst containing CSF (isodense, isointense) - Arachnoidal Bubbles - Strechted veins - No solid mass Dermoid cyst (n = 7; 5%) - Cystic lesion containing fat density - Fat in CT hypodense and in MRI hyperintense - In 20% calcification of the wall Sonography: - Well defined lobulated mass - Echo-rich / nonhomogeneous contents - Lack of ossification - Circumscribed mass - Dents in the bone - Fat tissue - Bone destruction Epidermal cyst (n = 2; 1,5%) - Round, lobulated lesion - Heterogeneous signal - Possible restricted diffusion - Lytic bone lesion filled with keratinous material - Liquid / gelatinous content Epidermoid cyst (n = 7; 5%) - Round, lobulated lesion - CT: sharply demarcated lytic lesion - MRI: T1 often slightly hyperintense to CSF T2 often iso- / slightly hyperintense to CSF - DWI: increased signal distinguishes cystic lesion from arachnoid cyst Sonography: - Partial destruction of the tabula externa - CFD: no perfusion - Completely intraosseous cyst X-ray: - Lytic bone lesion - Destroyed bone - Liquid, whitish pearl-colored mass - Vascularized skin - Bone thinning Fibroma (n = 1; 0,75%) - CT: sharply demarcated lytic lesion - MRI: no specific signal changes Skeletal scintigraphy: - Tracer uptake - Whitish, soft - Lytic bone lesion Hyperostosis (n = 9; 7%) - CT: osseous protrusion of the calvaria, starting from the tabula externa - MRI: no specific signal changes Skeletal scintigraphy: - Focal uptake - Only tabula externa affected Intraosseous hemangioma (n = 9; 7%) Fig. 2 e - CT: lytic-cystic lesion confined to the bone with involvement of the tabula interna and externa. - Low density. - No dura infiltration - MRI: contrast enhancement. T2 possible flow voids in large vessels T2* possible susceptibility artifact due blood breakdown in the vessels - Palpable swelling - Hypervascularized - Soft consistency - Bluish to purple-reddish color - Fibrotic capsule Meningioma (n = 20; 15%) Fig. 2 a–d WHO I Fig. 2 a–b - MRI: extra-axial mass with dural adhesion; omogeneous contrast enhancement; „dural tail“ in 30–85% of cases, but unspecific; T2: flow voids, possibly „sunburst” phenomenon - CT: bone thickening; transosseous growth; irregular cortex; hyperostosis; often calcifications - Necrosis and cystic parts are common, hemorrhage is rarely X-ray: - Callus formation - Infiltrative growth - Exophytic - Bone surface changed and uneven - Tumor intraosseous hard, intracranially soft - Hypervascularized - Dura can not be clearly defined - Reddish color WHO II - Like WHO I - Correlation between increased tumor grade and imaging with blurred tumor-brain delimitation, capsular and heterogeneous enhancement Skeletal scintigraphy: - No evidence of malignancy PET: - Metabolically active, osteodestructive - Avascular to hypervascularized - Swelling above bone level - Infiltrating growth - Tough, reddish WHO III Fig. 2 c–d - Like WHO I - Correlation between increased tumor grade and imaging with blurred tumor-brain delimitation, capsular and heterogeneous enhancement - Infiltrating growth - Hypervascularized - Hard capsule - Middle soft and yellowish Osteoid osteoma (n = 1; 0,75%) - Focal lytic lesion (“nidus”) within surrounding osteosclerotic reaction - MRI: enhancement of the nidus - Macroscopically no tumor visible Osteoma (n = 16; 12%) Fig. 2 f - Homogeneous bone-dense structure with partly cancellous partly hypersclerotic swelling - Exostosis of the tabula externa Skeletal scintigraphy: - Focal uptake - Solid bone swelling - Macroscopically intact bone structure - Soft borders around the bone Secondary neoplasia Metastasis (n = 19; 14%) Fig. 3 a–b - Most common malignant bone lesion - In patients > 40 years, metastasis should always be considered in the case of a lytic lesion - Variable morphology: lytic, plastic and mixed lesions - Variable contrast enhancement - Possible necrosis or hemorrhages - Dura infiltration Skeletal scintigraphy: - Uptake PET: - Metabolically active - Infiltrating growth - Lytic bone lesion - Tough and hard lesions - Bone thickening and very soft - Soft cancellous bone - Hypervascularized Plasmacytoma (n = 1; 0,75%) Fig. 3 d - Uni- (plasmacytoma) or multifocal (multiple myeloma) lytic lesion - Numerous, well-circumscribed lytic lesions („raindrop skull“) X-ray: - Numerous lytic bone lesions - Grown through the bone - Fibrotic tissue Spindle cell melanoma (n = 1; 0,75%) Fig. 3 c - No specific imaging findings in case of bone involvement - The isolated case showed a tumorous mass of the scalp with transosseous and broad-based dural infiltration - Reddened skin - Infiltrating growth Squamous cell carcinoma (n = 2; 1,5%) - Soft tissue process with perifocal osseous erosions - Bone destruction from the outside in, starting from the tabula externa - MRI: no specific findings Tumor-like lesions Aneurysmal bone cyst (n = 1; 0,75%) - Very rarely in the calvaria - Typically age under 30 years - Well circumscribed lytic lesion - MRI: multiple fluid levels with different signal behavior depending on the protein content - Capsule strongly ingrown with the dura Benign bone tissue with lytic lesions (n = 1; 0,75%) - No specific imaging findings - The isolated case showed a circumscribed lytic lesion in the diploe without erosion of the tabula interna and externa - Grayish colored cancellous bone CNS-Aspergillosis (n = 1; 0,75%) - No specific imaging findings - Perifocal lytic bone lesion and infiltration of the adjacent tissue - Altered, epidural, grayish tissue Connective tissue (with foreign body granuloma) (n = 3; 2%) - No specific imaging findings - The individual cases showed a lobulated, well circumscribed lytic lesion with hyperintense signal in T2 and mixed signal in T1. - - Tough capsule - Dermoid-typical content - Connective tissue in the area of the lytic lesion - Dura thinned - Fat tissue Fibrous dysplasia (n = 6; 4%) Fig. 4 c–e - Ground-glass opacities, homogeneously sclerotic - Thickened diploe - Mostly more than 1 bone affected (most often maxilla, orbit, frontal, ethmoid and sphenoid bone) - MRI not indicated for primary diagnostic - Often not distinguishable from Paget’s disease. In fibrous dysplasia the tabula externa is more often affected Skeletal scintigraphy: - Moderate focal uptake - Hypovascularized - Greyish mass - Bone soft, hypertrophied and reddish-glassy colored - No cancellous bone visible Gorham-Stout disease (n = 1; 0,75%) - Extremely rare - Nonspecific lytic bone lesion - Very soft bone - Almost no cancellous bone Histiocytosis (n = 20; 15%) Fig. 4 a –b - Well circumscribed lytic bone lesion. Calvaria is most frequently affected (frontal > parietal > temporal > occipital bone), most rarely also mastoid, mandible and orbit. Tabula interna more affected than tabula externa. - No periosteum reaction, possible perifocal soft tissue involvement - T1 iso- / hypointense; T2 hyperintense - Homogeneous contrast enhancement Skeletal scintigraphy: - Uptake, moderately metabolically active - Lytic bone lesion - Soft consistency - Grayish-glassy - Hypovascularized - Infiltrates the galea and periosteum Paget’s disease (n = 1; 0,75%) - Either well circumscribed bone defects or diffuse sclerotic, ground-glass opacities of the bone - Thickened diploe - The calvaria is most frequently affected, in isolated cases also the skull base - MRI not indicated for primary diagnostic - Manifest thickened cancellous bone Reactive bone remodeling zone (n = 1; 0,75%) - No specific imaging findings - The isolated case showed focal bone thinning with lobulated lytic lesion involving the diploe and the tabula interna and externa. - Lytic bone lesion Spindle cell tissue with abundant collagen connective tissue (n = 1; 0,75%) - No specific imaging findings - The isolated case showed a central lytic lesion with sclerosis around the border - Tough yellowish tissue Venous ectasia (n = 1; 0,75%) - Like hemangioma - Well circumscribed lytic lesion - Thin peripheral sclerotic border - No destruction of tabula interna and externa - Expansion of the bone trabeculae in the diploe - MRI: in T2 heterogeneous hyperintense signal, in T1 with contrast agent diffuse enhancement with time delayed filling Sonography: - Liquid-filled cavity - Intracranial connection - CFD: minimal flow - Bone thinned A complete resection has been achieved in 80% of cases (n = 107). A partial removal was performed in 14% (n = 18), a biopsy in 6% (n = 8) of cases. Intraoperative complications have only occurred in a few cases: intraoperative bleeding in 10 patients (7%), of which 3 are due to a sinus injury (2%). Accidental opening of the dura mater occurred in 7 patients (5%). 58% of the lesions (n = 77) were limited to the bone. The remaining lesions (n = 56; 42%) have shown an infiltrating growth in the adjacent tissue, especially in the dura in 32% of cases (n = 43). Infiltration up to arachnoid mater has been shown in 1.5% of cases (n = 2), up to the brain in 12% of cases (n = 16). Extracranially, infiltration to the skin has been shown in 10% of cases (n = 13), to the subcutaneous tissue in 4% of cases (n = 5), to the muscles in 1.5% of cases (n = 2), and to the galea in 9% of cases (n = 12). The described macroscopic peculiarities of the respective lesions are listed in Table 1 . - Postoperative course The final histopathological results are listed in Table 1 . Postoperative complications have occurred in < 5% of cases: cerebrospinal fluid fistula in 4% (n = 5), temporary neurological deficits in 3% (n = 4), sinus thrombosis in 2% (n = 3), wound healing disorders in 1.5% (n = 2) and an epidural hematoma in 0.75% of cases (n = 1). In the documented follow-ups (FU) (3–120 months), 10% of patients (n = 14) still reported pain or pressure at the site of surgery, 4% (n = 5) paresthesia, and another 4% (n = 5) still had a slight swelling in the surgical area. No permanent neurological disorders or deaths occurred. In patients with primary neoplasia (55%; n = 73; Table 1 ), a complete resection was performed in 44% (n = 59) of cases without developing a recurrence (FU 3–120 months, mean 32, SD 31). Partial resected meningiomas have a stable residual result in 6% (n = 8) of cases (FU 3–57 months, mean 25, SD 19.4). In 4.5% of cases (n = 6; 5 meningiomas and 1 epidermoid), there was a recurrence within 12–72 months (mean 29, SD 24). The meningiomas needed an adjuvant therapy, and the recurrent epidermoid has been resected again. Secondary neoplasia (18%; n = 24; Table 1 ) has been completely resected in 7.5% (n = 10) of cases (FU 3–9 months, mean 5, SD 2.5). Adjuvant therapy has occurred in 12% (n = 16) of cases, of which 1.5% of cases remained stable (n = 2, histologically metastases, FU 36 months), 0.75% decreasing (n = 1, histologically plasmacytoma, FU 28 months) and 5% have shown recurrent growth (n = 7, histologically metastases, squamous cell carcinoma and melanoma; FU 3–84 months, mean 34, SD 31). 4% (n = 5) have been operatively resected again, 1.5% of which (n = 2) were only on the scalp. (squamous cell carcinoma). Tumor-like lesions (27%; n = 36; Table 1 ) have been completely resected in 19.5% of cases (n = 26) without recurrence (FU 3–114 months, mean 43, SD 35). In 4.5% of cases (n = 6, histologically fibrous dysplasia, Gorham-Stout disease, Paget’s disease, histiocytosis; FU 4–95 months, mean 40, SD 39) a further treatment was performed with a stable course. In this group, recurrence has not been observed. Eight patients (6%) got lost from FU. Discussion The series of calvarial lesions presented here shows a variety of different entities (Table 1 ). Their incidence correlates with the cases already published [ 8 , 14 , 17 , 9 ]. Depending on the author, the lesions primarily originate from the bone are divided into three or four subcategories: primary neoplasia (in individual papers already divided into good and malignant primary neoplasia), secondary neoplasia and tumor-like lesions [ 17 , 22 ]. Primary osseous neoplasia come from the bone and are distinguished into benign and malignant lesions. Primary malignant lesions such as chordomas or sarcomas are not represented in our series, since they are frequently located at the skull base. Because a complete resection is not always possible, it is advisable to perform at least one biopsy or extended removal to ensure the diagnosis and initiate adjuvant treatment [ 9 , 10 ]. The most common benign lesions include meningiomas (Fig. 2 a–d), osteomas (Fig. 2 f) and intraosseous hemangiomas (Fig. 2 e). Osteomas (Fig. 2 f) grow slowly and are located on the tabula externa. The main complaints are the cosmetically disturbing swelling, less than the pain. If they are localized at the orbita, diplopia can occur [ 1 ]. Imaging shows a densely compact bone growth. No further treatment is necessary after a complete resection and there is an extremely low risk of recurrence [ 8 , 9 , 14 ]. Intraosseous hemangiomas (Fig. 2 e) are described in the literature more in women. As long as they are limited to the bone, they are often an asymptomatic random result [ 15 , 16 , 18 ]. Further growth can cause painful swelling. A typical “sunburst” phenomenon is shown in the CT [ 18 ]. In the MRI a variable arterio-venous contrast enhancement is described [ 8 ]. Complete resection down to healthy bone is recommended to minimize the recurrence risk [ 8 , 17 , 18 , 9 , 14 , 15 ]. Meningiomas (Fig. 2 a–d) are among the most common benign intracranial tumors. However, about 2% of meningiomas grow ectopic in the bone and infiltrate the adjacent tissue only secondarily [ 25 , 5 ]. Typical imaging findings are calcifications, homogeneous contrast enhancement, edema and a dural tail [ 8 , 9 , 14 ]. Our series includes different WHO grade of meningiomas, which also have significant different infiltrating growth. Adequate preoperative imaging is essential to minimize the intraoperative and postoperative risk for the patient. A complete resection is also recommended for meningiomas. If this is not possible, appropriate adjuvant therapy should be evaluated depending on the histology [ 5 ]. The most common entities of secondary neoplasia are metastasis (Fig. 3 a–b) of different primary carcinomas. In most cases, they are asymptomatic and stand out as random findings in the regular staging examinations. Patients can develop pain when the periost is infiltrated. By intracranial growth, the patients can also develop neurological deficits. Typical of the imaging are irregular osteolysis with remodeling of the bone, a variable contrast enhancement, and signs of a co-reaction of the surrounding tissue, for example, a perifocal edema [ 8 , 9 , 14 , 22 ]. A complete resection must be sought and subsequently, an adjuvant treatment should be started depending on the primary carcinoma [ 17 , 13 , 22 ]. The osteoclastic defects of a plasmacytoma (Fig. 3 d) also fall into the category of secondary neoplasia. Typical are pure osteolysis without remodeling of the bone [ 8 ]. Surgical resection with cover of the bone defect is recommended. In the event of systemic infestation, further treatment of the disease is necessary. In the scenario of a solitary manifestation and complete surgical resection, close-meshed follow-ups are necessary. In this case, further treatment is controversial discussed in the literature [ 3 , 11 , 6 , 19 ]. In the group of tumor-like lesions, there are, in particular, histiocytosis (Fig. 4 a–b), especially eosinophilic granuloma, and metabolic disorders, such as fibrous dysplasia (Fig. 4 c–e). Histiocytosis (Fig. 4 a–b) is a group of diseases with an increased proliferation of macrophages. Typical imaging findings are osteolysis with singular bone fragments within the lesion, as a sign of irregular bone destruction. MRI shows a homogeneous contrast enhancement limited to the bone without a co-reaction of the dura or perifocal edema (Table 1 ) [ 8 , 9 , 20 ]. The diagnosis can only be secured histologically. After this, a staging should been performed. If the lesion is isolated at the skull, no further therapy is necessary, but for multifocal manifestations, chemotherapy and radiotherapy are recommended [ 2 , 20 ]. Another known bone malformation is fibrous dysplasia (Fig. 4 c–e), which is due to overactivity of osteoclasts and leads to disturbed bone differentiation [ 7 ]. The malformation can affect all bones of the body, including the skull. Patients often complain of severe pain and have swelling or fractures. A distinction is made between the monostotic form (Fig. 4 c–d), which can be treated by surgical resection and covering the defect [ 4 ], from the polyostotic form (Fig. 4 e), in which symptomatic treatment with analgesics and bisphosphonates takes place. In the polyostotic form, only partial removal makes sense if important structures are compressed and patients develop complaints [ 7 ]. A typical finding in the CT-scan are ground-glass opacities [ 8 , 17 , 4 ]. In our series, secondary the bone-infiltrating lesions also occurred, such as squamous cell carcinoma and malignant melanoma (Fig. 3 c). These, too, have an osteolytic growth; depending on the stage of the disease, the infiltration can range from the skin to intracranial. Surgical resection and cover of the defect with subsequent systemic adjuvant therapy must be planned [ 24 , 21 ]. Based on the imaging, suspicions of the underlying lesion can be obtained (Table 1 and Figs. 2 – 4 ). The limits of a lesion can suggest conclusions about the speed of growth: smooth edges and a homogeneous internal structure mark more of a benign, slowly growing process; irregular edges with inhomogeneous internal structure point, rather, to a malignant, fast-growing process. Also, slowly growing lesions are usually limited to the bone, while fast-growing show an infiltrating growth in adjacent tissue. With the administration of a contrast agent, further conclusions can be drawn about the dignity of the lesion. While reactive or scarring changes in the dura have a linear, homogeneous contrast enhancement, tumor infiltration is often characterized by irregular, inhomogeneous contrast enhancement. If the dura looks distant from the bone and, thus, the epidural space is visible, a dura infiltration is unlikely [ 8 , 9 , 14 , 17 , 12 ]. The management of patients with calvarial lesions should be interdisciplinary, as with other oncological diseases. The general practitioner is usually the first contact for the patient, as the lesions are often a random results and there are no complaints. To draw conclusions about the possible entity of the lesion, a targeted image is required [ 8 , 9 , 14 , 17 , 12 ]. The suspected diagnoses can be limited and the further procedure planned. In any case, an surgical extraction of a tissue sample is necessary to ensure the diagnosis. If properly planned, the operation is a low-risk procedure without significant morbidity and mortality [ 12 , 17 , 22 ]. Important imaging aspects are, in particular, the extension of possible infiltration and the course of the large blood vessels, especially intracranially of the sinus. Therefore, we recommend the implementation of a CT and MRI with and without contrast agent. Some lesions can have a similar extension on the bone, but differ significantly in their intracranial spreading (Fig. 2 a–b vs 2c–d). The medical history, clinical complaints and differential diagnoses must be taken into account together to evaluate the urgency of histological examination. While an underlying carcinoma requires a timely confirmation of a possible metastasis to initiate a targeted adjuvant treatment, in the case of a purely intraosseous lesion with a homogeneous internal structure and without any co-reaction of the adjacent tissue and without any complaints, an initial follow-up observation is also acceptable and surgical care is not urgent. If an operation takes place, a complete resection with cover of the defect must be planned. Declarations Funding There was no funding for this study Conflict of interest / Competing interests The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. None of the authors have potential conflicts of interest to be disclosed. Availability of data and material All data are included in the manuscript. Code availability Not applicable Ethics approval This retrospective study was approved by the ethics committee of the Eberhard Karls University Tuebingen (registration no. 028/2019BO2). All procedures performed were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Consent to participate and publication Written consent was obtained from the patients in order to evaluate and publish the data anonymously Authors’ contributions All authors listed have made substantial, direct, and intellectual contribution to the work and approved it for publications. INK contributed to data acquisition, analysis, and interpretation of data, statistical analysis, and the writing of the first draft. JMD was responsible for the interpretation of imaging findings, the review and critique of the final manuscript. 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Radiol Case Rep 14:1478-1482. doi:10.1016/j.radcr.2019.09.009 Soma PF, Chibbaro S, Makiese O, Marsella M, Diemidio P, Fricia M, Passanisi M, Catania V, Sirago P, Ventura F (2008) Aggressive scalp carcinoma with intracranial extension: a multidisciplinary experience of 25 patients with long-term follow-up. J Clin Neurosci 15:988-992. doi:10.1016/j.jocn.2007.09.014 Stark AM, Eichmann T, Mehdorn HM (2003) Skull metastases: clinical features, differential diagnosis, and review of the literature. Surg Neurol 60:219-225; discussion 225-216. doi:10.1016/s0090-3019(03)00269-6 Vital RB, Hamamoto Filho PT, Lapate RL, Martins VZ, de Oliveira Lima F, Romero FR, Zanini MA (2015) Calvarial ectopic meningothelial meningioma. Int J Surg Case Rep 10:69-72. doi:10.1016/j.ijscr.2015.03.033 Wollina U, Kittner T, Nowak A (2019) Nonmelanoma Skin Cancer with Skull Infiltration and Cranial Involvement. Open Access Maced J Med Sci 7:3030-3033. doi:10.3889/oamjms.2019.416 Yilmaz A, Musluman M, Aydin Y (2010) Primary osteolytic intraosseous meningioma of the frontal bone. Neurol Neurochir Pol 44:415-418. doi:10.1016/s0028-3843(14)60302-9 Cite Share Download PDF Status: Published Journal Publication published 22 Mar, 2021 Read the published version in Neurosurgical Review → Version 1 posted Reviews received at journal 02 Feb, 2021 First submitted to journal 21 Jan, 2021 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-161395","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Original Article","associatedPublications":[],"authors":[{"id":9828912,"identity":"c4205e96-403c-4af2-8458-5a82c95d593f","order_by":0,"name":"Isabella Nasi-Kordhishti","email":"data:image/png;base64,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","orcid":"https://orcid.org/0000-0003-2226-4958","institution":"University Hospital Tübingen Department of Neurosurgery: Universitatsklinik fur Neurochirurgie","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Isabella","middleName":"","lastName":"Nasi-Kordhishti","suffix":""},{"id":9828913,"identity":"8cfa9237-dba8-4b48-9b0b-1507449fd151","order_by":1,"name":"Johann-Martin Hempel","email":"","orcid":"","institution":"Eberhard Karls University Tübingen, Germany","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Johann-Martin","middleName":"","lastName":"Hempel","suffix":""},{"id":9828914,"identity":"2912afb9-b5c8-466e-88a3-dbcb561acbda","order_by":2,"name":"Florian Heinrich Ebner","email":"","orcid":"","institution":"Eberhard Karls University Tübingen, Germany ","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Florian","middleName":"Heinrich","lastName":"Ebner","suffix":""},{"id":9828915,"identity":"01d6b105-a4e6-483f-af48-b5c4b814998c","order_by":3,"name":"Marcos Tatagiba","email":"","orcid":"","institution":"Eberhard Karls University Tübingen, Germany ","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Marcos","middleName":"","lastName":"Tatagiba","suffix":""}],"badges":[],"createdAt":"2021-01-27 18:23:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-161395/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-161395/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10143-021-01521-5","type":"published","date":"2021-03-22T19:04:06+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":5548585,"identity":"de3a5a23-14c5-4e67-b713-45327f98b517","added_by":"auto","created_at":"2021-02-02 18:44:08","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":617834,"visible":true,"origin":"","legend":"a: Age distribution in years. B: Preoperative complaints. FND: focal neurological deficits.","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-161395/v1/46272c38da0c091d68ced0c9.png"},{"id":5548730,"identity":"f45a7ebd-c77d-41bb-86c6-f63831ec5589","added_by":"auto","created_at":"2021-02-02 18:47:08","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1555390,"visible":true,"origin":"","legend":"Primary neoplasia. a+b: Intraosseous meningioma WHO I. c+d: Meningioma WHO Grad III with infiltrative growth. e: Intraosseous hemangioma. f: Osteoma","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-161395/v1/a5768727d371143cff7c3b8a.png"},{"id":5548584,"identity":"ea84a627-e765-4e22-95ae-5ed2273e9f70","added_by":"auto","created_at":"2021-02-02 18:44:08","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":497149,"visible":true,"origin":"","legend":"Secundary neoplasia. a+b: Metastasis. c: Malignant melanoma with infiltrative growth and bone destruction. d: Osteolytic lesion in plasmacytoma ","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-161395/v1/9d9ea5b4f27a976f2e78ab11.png"},{"id":5548587,"identity":"ec2da288-8ff2-47db-bae3-61f6eec920ea","added_by":"auto","created_at":"2021-02-02 18:44:08","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":640145,"visible":true,"origin":"","legend":"Tumor-like lesions. a+b: Histocytosis. c+d: monostotic fibrous dysplasia. e: polyostotic fibrous dysplasia.","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-161395/v1/f89ae0c88b952f0664a17a28.png"},{"id":13654301,"identity":"1161c038-5452-4483-ade0-1b5e0919cd1c","added_by":"auto","created_at":"2021-09-17 09:57:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3224089,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-161395/v1/65489917-50fe-46b4-8c46-72d87c560add.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eCalvarial Lesions: Overview of Imaging Features and Neurosurgical Management\u003c/p\u003e","fulltext":[{"header":"Introduction","content":" \u003cp\u003eIntraosseous lesions of the calvarium are often slow, progressive processes that manifested in swelling, local pain or sensitivity disorders. Asymptomatic processes are often described as random findings in the imaging. A variety of diseases can hide behind such a lesion. We distinguish between lesions that originate primarily from the bone and those that present a secondary bone infiltration. Depending on the author, the first category is divided into three or four subcategories: primary neoplasia (in individual papers already divided into good and malignant primary neoplasia), secondary neoplasia and tumor-like lesions [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Using adequate imaging as computed tomography (CT) and magnetic resonance imaging (MRI), suspicions can be drawn about the dignity of the present lesion, especially if the clinical symptoms and the case history of the patients are included [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. A definitive statement about the dignity of a lesion can only be obtained by histopathological examination. The clinical management methods of calvarial lesions differ greatly depending on the underlying entity [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Most benign lesions, such as osteomas, meningiomas or intraosseous hemangiomas, can usually be completely resected and do not need further treatment [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, malignant lesions, such as metastasis or osteolysis in plasmacytoma, potentially require an adjuvant therapy such as chemotherapy, immunotherapy or radiation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Rare diseases such as histiocytosis require individual diagnostic and therapeutic evaluations [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSince calvarial lesions are rare diseases in neurosurgery, only a few single case reports and reviews have been published. This research aims to present an overview of calvarial lesions based on typical imaging features and the histopathological results, as well as the neurosurgical management.\u003c/p\u003e "},{"header":"Materials And Methods","content":" \u003cp\u003eIncluded are all children and adults with lesion of the clavarium and orbita who were operated in our department between 2004 and 2017. The pre-, intra- and postoperative data, as well as the imaging and histopathological findings, have been analyzed retrospectively. All patients with solitary lesions at the skull base were excluded. Since this is a surgical series, patients who have been treated only conservatively are not included. This case series does not claim to be a presentation of all possible disease entities.\u003c/p\u003e \u003cp\u003eAll statistical tests were performed using JMP 13 (SAS Institute Inc., Cary, NC). Descriptive data are shown as mean, standard deviation (SD) and percentage.\u003c/p\u003e "},{"header":"Results","content":"\u003ch2\u003e- Pre- and intraoperative evaluation\u003c/h2\u003e\n\u003cp\u003eA total of 133 patients were operated, 74 of whom were women and 59 were men. The age distribution of 0\u0026ndash;95 years is homogeneously distributed over all decades with a mean of 42 years and a standard deviation (SD) of 24.7 (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe patients\u0026rsquo; main complaints (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb) were swelling (n\u0026thinsp;=\u0026thinsp;91; 68%), pain (n\u0026thinsp;=\u0026thinsp;61; 46%), and subjective cosmetic impairment (n\u0026thinsp;=\u0026thinsp;58; 44%). Rarely represented were focal neurological deficits (FND) (N\u0026thinsp;=\u0026thinsp;22; 17%), feelings of tension of the skin (n\u0026thinsp;=\u0026thinsp;21; 16%), exophthalmos (n\u0026thinsp;=\u0026thinsp;8; 6%), diplopia (n\u0026thinsp;=\u0026thinsp;7; 5%), and dents in the skin (n\u0026thinsp;=\u0026thinsp;4; 3%). Only 23 patients have not complained of any symptoms.\u003c/p\u003e\n\u003cp\u003eThe location of the lesions is distributed in every part of the skull with a clear frontal prevalence (n\u0026thinsp;=\u0026thinsp;55; 41%). Parietal (n\u0026thinsp;=\u0026thinsp;26; 19%), occipital (n\u0026thinsp;=\u0026thinsp;20; 15%), orbital (n\u0026thinsp;=\u0026thinsp;12; 9%), sutural (n\u0026thinsp;=\u0026thinsp;7; 5%) and temporal (n\u0026thinsp;=\u0026thinsp;4; 3%) lesions are rarer. In two newborns, a lesion was found directly on the fontanel (1.5%).\u003c/p\u003e\n\u003cp\u003eAll patients, except the two newborns, have received preoperative cranial imaging using CT and MRI with and without contrast enhancement. The newborns were dispensed with CT diagnostics. Also, an X-ray, sonography, PET-CT or bone scintigraphy was performed preoperatively in individual cases. The typical findings for the lesions are described in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e after the classification of the postoperatively obtained histology.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eImaging and intraoperative macroscopically findings of calvarial lesions after histological diagnosis.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCFD: color flow doppler sonography; CNS: central nervous system; CSF: cerebrospinal fluid; CT: Computed tomography; MRI: magnetic resonance imaging; PET: Positron-Emission-Tomography.\u003c/em\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eTomography findings\u003c/p\u003e\n\u003cp\u003eCT and MRI\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eOther imaging methods\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMacroscopically intraoperative\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e\u003cspan class=\"ItalicUnderline\"\u003ePrimary neoplasia\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eArachnoidal cyst (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Calvarial (Tabula interna and externa) thinning\u003c/p\u003e\n\u003cp\u003e- Well circumscribed cyst containing CSF (isodense, isointense)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Arachnoidal Bubbles\u003c/p\u003e\n\u003cp\u003e- Strechted veins\u003c/p\u003e\n\u003cp\u003e- No solid mass\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eDermoid cyst (n\u0026thinsp;=\u0026thinsp;7; 5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Cystic lesion containing fat density\u003c/p\u003e\n\u003cp\u003e- Fat in CT hypodense and in MRI hyperintense\u003c/p\u003e\n\u003cp\u003e- In 20% calcification of the wall\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSonography:\u003c/p\u003e\n\u003cp\u003e- Well defined lobulated mass\u003c/p\u003e\n\u003cp\u003e- Echo-rich / nonhomogeneous contents\u003c/p\u003e\n\u003cp\u003e- Lack of ossification\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Circumscribed mass\u003c/p\u003e\n\u003cp\u003e- Dents in the bone\u003c/p\u003e\n\u003cp\u003e- Fat tissue\u003c/p\u003e\n\u003cp\u003e- Bone destruction\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eEpidermal cyst (n\u0026thinsp;=\u0026thinsp;2; 1,5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Round, lobulated lesion\u003c/p\u003e\n\u003cp\u003e- Heterogeneous signal\u003c/p\u003e\n\u003cp\u003e- Possible restricted diffusion\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Lytic bone lesion filled with keratinous material\u003c/p\u003e\n\u003cp\u003e- Liquid / gelatinous content\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eEpidermoid cyst (n\u0026thinsp;=\u0026thinsp;7; 5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Round, lobulated lesion\u003c/p\u003e\n\u003cp\u003e- CT: sharply demarcated lytic lesion\u003c/p\u003e\n\u003cp\u003e- MRI:\u003c/p\u003e\n\u003cp\u003eT1 often slightly hyperintense to CSF\u003c/p\u003e\n\u003cp\u003eT2 often iso- / slightly hyperintense to CSF\u003c/p\u003e\n\u003cp\u003e- DWI: increased signal distinguishes cystic lesion from arachnoid cyst\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSonography:\u003c/p\u003e\n\u003cp\u003e- Partial destruction of the tabula externa\u003c/p\u003e\n\u003cp\u003e- CFD: no perfusion\u003c/p\u003e\n\u003cp\u003e- Completely intraosseous cyst\u003c/p\u003e\n\u003cp\u003eX-ray:\u003c/p\u003e\n\u003cp\u003e- Lytic bone lesion\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Destroyed bone\u003c/p\u003e\n\u003cp\u003e- Liquid, whitish pearl-colored mass\u003c/p\u003e\n\u003cp\u003e- Vascularized skin\u003c/p\u003e\n\u003cp\u003e- Bone thinning\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eFibroma (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- CT: sharply demarcated lytic lesion\u003c/p\u003e\n\u003cp\u003e- MRI: no specific signal changes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Tracer uptake\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Whitish, soft\u003c/p\u003e\n\u003cp\u003e- Lytic bone lesion\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eHyperostosis (n\u0026thinsp;=\u0026thinsp;9; 7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- CT: osseous protrusion of the calvaria,\u003c/p\u003e\n\u003cp\u003estarting from the tabula externa\u003c/p\u003e\n\u003cp\u003e- MRI: no specific signal changes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Focal uptake\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Only tabula externa affected\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eIntraosseous hemangioma (n\u0026thinsp;=\u0026thinsp;9; 7%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ee\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- CT: lytic-cystic lesion confined to the bone with involvement of the tabula interna and externa.\u003c/p\u003e\n\u003cp\u003e- Low density.\u003c/p\u003e\n\u003cp\u003e- No dura infiltration\u003c/p\u003e\n\u003cp\u003e- MRI: contrast enhancement.\u003c/p\u003e\n\u003cp\u003eT2 possible flow voids in large vessels\u003c/p\u003e\n\u003cp\u003eT2* possible susceptibility artifact due blood breakdown in the vessels\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Palpable swelling\u003c/p\u003e\n\u003cp\u003e- Hypervascularized\u003c/p\u003e\n\u003cp\u003e- Soft consistency\u003c/p\u003e\n\u003cp\u003e- Bluish to purple-reddish color\u003c/p\u003e\n\u003cp\u003e- Fibrotic capsule\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eMeningioma (n\u0026thinsp;=\u0026thinsp;20; 15%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026ndash;d\u003c/p\u003e\n\u003cp\u003eWHO I Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026ndash;b\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- MRI: extra-axial mass with dural adhesion; omogeneous contrast enhancement; \u0026bdquo;dural tail\u0026ldquo; in 30\u0026ndash;85% of cases, but unspecific; T2: flow voids, possibly \u0026bdquo;sunburst\u0026rdquo; phenomenon\u003c/p\u003e\n\u003cp\u003e- CT: bone thickening; transosseous growth; irregular cortex; hyperostosis; often calcifications\u003c/p\u003e\n\u003cp\u003e- Necrosis and cystic parts are common, hemorrhage is rarely\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eX-ray:\u003c/p\u003e\n\u003cp\u003e- Callus formation\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Infiltrative growth\u003c/p\u003e\n\u003cp\u003e- Exophytic\u003c/p\u003e\n\u003cp\u003e- Bone surface changed and uneven\u003c/p\u003e\n\u003cp\u003e- Tumor intraosseous hard, intracranially soft\u003c/p\u003e\n\u003cp\u003e- Hypervascularized\u003c/p\u003e\n\u003cp\u003e- Dura can not be clearly defined\u003c/p\u003e\n\u003cp\u003e- Reddish color\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eWHO II\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Like WHO I\u003c/p\u003e\n\u003cp\u003e- Correlation between increased tumor grade and imaging with blurred tumor-brain delimitation, capsular and heterogeneous enhancement\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- No evidence of malignancy\u003c/p\u003e\n\u003cp\u003ePET:\u003c/p\u003e\n\u003cp\u003e- Metabolically active, osteodestructive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Avascular to hypervascularized\u003c/p\u003e\n\u003cp\u003e- Swelling above bone level\u003c/p\u003e\n\u003cp\u003e- Infiltrating growth\u003c/p\u003e\n\u003cp\u003e- Tough, reddish\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eWHO III Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ec\u0026ndash;d\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Like WHO I\u003c/p\u003e\n\u003cp\u003e- Correlation between increased tumor grade and imaging with blurred tumor-brain delimitation, capsular and heterogeneous enhancement\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Infiltrating growth\u003c/p\u003e\n\u003cp\u003e- Hypervascularized\u003c/p\u003e\n\u003cp\u003e- Hard capsule\u003c/p\u003e\n\u003cp\u003e- Middle soft and yellowish\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eOsteoid osteoma (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Focal lytic lesion (\u0026ldquo;nidus\u0026rdquo;) within surrounding osteosclerotic reaction\u003c/p\u003e\n\u003cp\u003e- MRI: enhancement of the nidus\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Macroscopically no tumor visible\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eOsteoma (n\u0026thinsp;=\u0026thinsp;16; 12%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ef\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Homogeneous bone-dense structure with partly cancellous partly hypersclerotic swelling\u003c/p\u003e\n\u003cp\u003e- Exostosis of the tabula externa\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Focal uptake\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Solid bone swelling\u003c/p\u003e\n\u003cp\u003e- Macroscopically intact bone structure\u003c/p\u003e\n\u003cp\u003e- Soft borders around the bone\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e\u003cspan class=\"ItalicUnderline\"\u003eSecondary neoplasia\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eMetastasis (n\u0026thinsp;=\u0026thinsp;19; 14%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea\u0026ndash;b\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Most common malignant bone lesion\u003c/p\u003e\n\u003cp\u003e- In patients\u0026thinsp;\u0026gt;\u0026thinsp;40 years, metastasis should always be considered in the case of a lytic lesion\u003c/p\u003e\n\u003cp\u003e- Variable morphology: lytic, plastic and mixed lesions\u003c/p\u003e\n\u003cp\u003e- Variable contrast enhancement\u003c/p\u003e\n\u003cp\u003e- Possible necrosis or hemorrhages\u003c/p\u003e\n\u003cp\u003e- Dura infiltration\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Uptake\u003c/p\u003e\n\u003cp\u003ePET:\u003c/p\u003e\n\u003cp\u003e- Metabolically active\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Infiltrating growth\u003c/p\u003e\n\u003cp\u003e- Lytic bone lesion\u003c/p\u003e\n\u003cp\u003e- Tough and hard lesions\u003c/p\u003e\n\u003cp\u003e- Bone thickening and very soft\u003c/p\u003e\n\u003cp\u003e- Soft cancellous bone\u003c/p\u003e\n\u003cp\u003e- Hypervascularized\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003ePlasmacytoma (n\u0026thinsp;=\u0026thinsp;1; 0,75%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ed\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Uni- (plasmacytoma) or multifocal (multiple myeloma) lytic lesion\u003c/p\u003e\n\u003cp\u003e- Numerous, well-circumscribed lytic lesions (\u0026bdquo;raindrop skull\u0026ldquo;)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eX-ray:\u003c/p\u003e\n\u003cp\u003e- Numerous lytic bone lesions\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Grown through the bone\u003c/p\u003e\n\u003cp\u003e- Fibrotic tissue\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eSpindle cell melanoma (n\u0026thinsp;=\u0026thinsp;1; 0,75%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ec\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings in case of bone involvement\u003c/p\u003e\n\u003cp\u003e- The isolated case showed a tumorous mass of the scalp with transosseous and broad-based dural infiltration\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Reddened skin\u003c/p\u003e\n\u003cp\u003e- Infiltrating growth\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eSquamous cell carcinoma (n\u0026thinsp;=\u0026thinsp;2; 1,5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Soft tissue process with perifocal osseous erosions\u003c/p\u003e\n\u003cp\u003e- Bone destruction from the outside in, starting from the tabula externa\u003c/p\u003e\n\u003cp\u003e- MRI: no specific findings\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003e\u003cspan class=\"ItalicUnderline\"\u003eTumor-like lesions\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eAneurysmal bone cyst (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Very rarely in the calvaria\u003c/p\u003e\n\u003cp\u003e- Typically age under 30 years\u003c/p\u003e\n\u003cp\u003e- Well circumscribed lytic lesion\u003c/p\u003e\n\u003cp\u003e- MRI: multiple fluid levels with different signal behavior depending on the protein content\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Capsule strongly ingrown with the dura\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eBenign bone tissue with lytic lesions (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings\u003c/p\u003e\n\u003cp\u003e- The isolated case showed a circumscribed lytic lesion in the diploe without erosion of the tabula interna and externa\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Grayish colored cancellous bone\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eCNS-Aspergillosis (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings\u003c/p\u003e\n\u003cp\u003e- Perifocal lytic bone lesion and infiltration of the adjacent tissue\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Altered, epidural, grayish tissue\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eConnective tissue (with foreign body granuloma) (n\u0026thinsp;=\u0026thinsp;3; 2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings\u003c/p\u003e\n\u003cp\u003e- The individual cases showed a lobulated, well circumscribed lytic lesion with hyperintense signal in T2 and mixed signal in T1.\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Tough capsule\u003c/p\u003e\n\u003cp\u003e- Dermoid-typical content\u003c/p\u003e\n\u003cp\u003e- Connective tissue in the area of the lytic lesion\u003c/p\u003e\n\u003cp\u003e- Dura thinned\u003c/p\u003e\n\u003cp\u003e- Fat tissue\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eFibrous dysplasia (n\u0026thinsp;=\u0026thinsp;6; 4%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ec\u0026ndash;e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Ground-glass opacities, homogeneously sclerotic\u003c/p\u003e\n\u003cp\u003e- Thickened diploe\u003c/p\u003e\n\u003cp\u003e- Mostly more than 1 bone affected (most often maxilla, orbit, frontal, ethmoid and sphenoid bone)\u003c/p\u003e\n\u003cp\u003e- MRI not indicated for primary diagnostic\u003c/p\u003e\n\u003cp\u003e- Often not distinguishable from Paget\u0026rsquo;s disease. In fibrous dysplasia the tabula externa is more often affected\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Moderate focal uptake\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Hypovascularized\u003c/p\u003e\n\u003cp\u003e- Greyish mass\u003c/p\u003e\n\u003cp\u003e- Bone soft, hypertrophied and reddish-glassy colored\u003c/p\u003e\n\u003cp\u003e- No cancellous bone visible\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eGorham-Stout disease (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Extremely rare\u003c/p\u003e\n\u003cp\u003e- Nonspecific lytic bone lesion\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Very soft bone\u003c/p\u003e\n\u003cp\u003e- Almost no cancellous bone\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eHistiocytosis (n\u0026thinsp;=\u0026thinsp;20; 15%) Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea \u0026ndash;b\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Well circumscribed lytic bone lesion. Calvaria is most frequently affected (frontal\u0026thinsp;\u0026gt;\u0026thinsp;parietal\u0026thinsp;\u0026gt;\u0026thinsp;temporal\u0026thinsp;\u0026gt;\u0026thinsp;occipital bone), most rarely also mastoid, mandible and orbit. Tabula interna more affected than tabula externa.\u003c/p\u003e\n\u003cp\u003e- No periosteum reaction, possible perifocal soft tissue involvement\u003c/p\u003e\n\u003cp\u003e- T1 iso- / hypointense; T2 hyperintense\u003c/p\u003e\n\u003cp\u003e- Homogeneous contrast enhancement\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSkeletal scintigraphy:\u003c/p\u003e\n\u003cp\u003e- Uptake, moderately metabolically active\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Lytic bone lesion\u003c/p\u003e\n\u003cp\u003e- Soft consistency\u003c/p\u003e\n\u003cp\u003e- Grayish-glassy\u003c/p\u003e\n\u003cp\u003e- Hypovascularized\u003c/p\u003e\n\u003cp\u003e- Infiltrates the galea and periosteum\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003ePaget\u0026rsquo;s disease (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Either well circumscribed bone defects or diffuse sclerotic, ground-glass opacities of the bone\u003c/p\u003e\n\u003cp\u003e- Thickened diploe\u003c/p\u003e\n\u003cp\u003e- The calvaria is most frequently affected, in isolated cases also the skull base\u003c/p\u003e\n\u003cp\u003e- MRI not indicated for primary diagnostic\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Manifest thickened cancellous bone\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eReactive bone remodeling zone (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings\u003c/p\u003e\n\u003cp\u003e- The isolated case showed focal bone thinning with lobulated lytic lesion involving the diploe and the tabula interna and externa.\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Lytic bone lesion\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eSpindle cell tissue with abundant collagen connective tissue (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- No specific imaging findings\u003c/p\u003e\n\u003cp\u003e- The isolated case showed a central lytic lesion with sclerosis around the border\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Tough yellowish tissue\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eVenous ectasia (n\u0026thinsp;=\u0026thinsp;1; 0,75%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Like hemangioma\u003c/p\u003e\n\u003cp\u003e- Well circumscribed lytic lesion\u003c/p\u003e\n\u003cp\u003e- Thin peripheral sclerotic border\u003c/p\u003e\n\u003cp\u003e- No destruction of tabula interna and externa\u003c/p\u003e\n\u003cp\u003e- Expansion of the bone trabeculae in the diploe\u003c/p\u003e\n\u003cp\u003e- MRI: in T2 heterogeneous hyperintense signal, in T1 with contrast agent diffuse enhancement with time delayed filling\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSonography:\u003c/p\u003e\n\u003cp\u003e- Liquid-filled cavity\u003c/p\u003e\n\u003cp\u003e- Intracranial connection\u003c/p\u003e\n\u003cp\u003e- CFD: minimal flow\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e- Bone thinned\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eA complete resection has been achieved in 80% of cases (n\u0026thinsp;=\u0026thinsp;107). A partial removal was performed in 14% (n\u0026thinsp;=\u0026thinsp;18), a biopsy in 6% (n\u0026thinsp;=\u0026thinsp;8) of cases. Intraoperative complications have only occurred in a few cases: intraoperative bleeding in 10 patients (7%), of which 3 are due to a sinus injury (2%). Accidental opening of the dura mater occurred in 7 patients (5%).\u003c/p\u003e\n\u003cp\u003e58% of the lesions (n\u0026thinsp;=\u0026thinsp;77) were limited to the bone. The remaining lesions (n\u0026thinsp;=\u0026thinsp;56; 42%) have shown an infiltrating growth in the adjacent tissue, especially in the dura in 32% of cases (n\u0026thinsp;=\u0026thinsp;43). Infiltration up to arachnoid mater has been shown in 1.5% of cases (n\u0026thinsp;=\u0026thinsp;2), up to the brain in 12% of cases (n\u0026thinsp;=\u0026thinsp;16). Extracranially, infiltration to the skin has been shown in 10% of cases (n\u0026thinsp;=\u0026thinsp;13), to the subcutaneous tissue in 4% of cases (n\u0026thinsp;=\u0026thinsp;5), to the muscles in 1.5% of cases (n\u0026thinsp;=\u0026thinsp;2), and to the galea in 9% of cases (n\u0026thinsp;=\u0026thinsp;12). The described macroscopic peculiarities of the respective lesions are listed in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003ch2\u003e- Postoperative course\u003c/h2\u003e\n\u003cp\u003eThe final histopathological results are listed in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Postoperative complications have occurred in \u0026lt;\u0026thinsp;5% of cases: cerebrospinal fluid fistula in 4% (n\u0026thinsp;=\u0026thinsp;5), temporary neurological deficits in 3% (n\u0026thinsp;=\u0026thinsp;4), sinus thrombosis in 2% (n\u0026thinsp;=\u0026thinsp;3), wound healing disorders in 1.5% (n\u0026thinsp;=\u0026thinsp;2) and an epidural hematoma in 0.75% of cases (n\u0026thinsp;=\u0026thinsp;1). In the documented follow-ups (FU) (3\u0026ndash;120 months), 10% of patients (n\u0026thinsp;=\u0026thinsp;14) still reported pain or pressure at the site of surgery, 4% (n\u0026thinsp;=\u0026thinsp;5) paresthesia, and another 4% (n\u0026thinsp;=\u0026thinsp;5) still had a slight swelling in the surgical area. No permanent neurological disorders or deaths occurred.\u003c/p\u003e\n\u003cp\u003eIn patients with primary neoplasia (55%; n\u0026thinsp;=\u0026thinsp;73; Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e), a complete resection was performed in 44% (n\u0026thinsp;=\u0026thinsp;59) of cases without developing a recurrence (FU 3\u0026ndash;120 months, mean 32, SD 31). Partial resected meningiomas have a stable residual result in 6% (n\u0026thinsp;=\u0026thinsp;8) of cases (FU 3\u0026ndash;57 months, mean 25, SD 19.4). In 4.5% of cases (n\u0026thinsp;=\u0026thinsp;6; 5 meningiomas and 1 epidermoid), there was a recurrence within 12\u0026ndash;72 months (mean 29, SD 24). The meningiomas needed an adjuvant therapy, and the recurrent epidermoid has been resected again.\u003c/p\u003e\n\u003cp\u003eSecondary neoplasia (18%; n\u0026thinsp;=\u0026thinsp;24; Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) has been completely resected in 7.5% (n\u0026thinsp;=\u0026thinsp;10) of cases (FU 3\u0026ndash;9 months, mean 5, SD 2.5). Adjuvant therapy has occurred in 12% (n\u0026thinsp;=\u0026thinsp;16) of cases, of which 1.5% of cases remained stable (n\u0026thinsp;=\u0026thinsp;2, histologically metastases, FU 36 months), 0.75% decreasing (n\u0026thinsp;=\u0026thinsp;1, histologically plasmacytoma, FU 28 months) and 5% have shown recurrent growth (n\u0026thinsp;=\u0026thinsp;7, histologically metastases, squamous cell carcinoma and melanoma; FU 3\u0026ndash;84 months, mean 34, SD 31). 4% (n\u0026thinsp;=\u0026thinsp;5) have been operatively resected again, 1.5% of which (n\u0026thinsp;=\u0026thinsp;2) were only on the scalp. (squamous cell carcinoma).\u003c/p\u003e\n\u003cp\u003eTumor-like lesions (27%; n\u0026thinsp;=\u0026thinsp;36; Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) have been completely resected in 19.5% of cases (n\u0026thinsp;=\u0026thinsp;26) without recurrence (FU 3\u0026ndash;114 months, mean 43, SD 35). In 4.5% of cases (n\u0026thinsp;=\u0026thinsp;6, histologically fibrous dysplasia, Gorham-Stout disease, Paget\u0026rsquo;s disease, histiocytosis; FU 4\u0026ndash;95 months, mean 40, SD 39) a further treatment was performed with a stable course. In this group, recurrence has not been observed.\u003c/p\u003e\n\u003cp\u003eEight patients (6%) got lost from FU.\u003c/p\u003e"},{"header":"Discussion","content":" \u003cp\u003eThe series of calvarial lesions presented here shows a variety of different entities (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Their incidence correlates with the cases already published [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Depending on the author, the lesions primarily originate from the bone are divided into three or four subcategories: primary neoplasia (in individual papers already divided into good and malignant primary neoplasia), secondary neoplasia and tumor-like lesions [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrimary osseous neoplasia come from the bone and are distinguished into benign and malignant lesions. Primary malignant lesions such as chordomas or sarcomas are not represented in our series, since they are frequently located at the skull base. Because a complete resection is not always possible, it is advisable to perform at least one biopsy or extended removal to ensure the diagnosis and initiate adjuvant treatment [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The most common benign lesions include meningiomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026ndash;d), osteomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef) and intraosseous hemangiomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee). Osteomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef) grow slowly and are located on the tabula externa. The main complaints are the cosmetically disturbing swelling, less than the pain. If they are localized at the orbita, diplopia can occur [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Imaging shows a densely compact bone growth. No further treatment is necessary after a complete resection and there is an extremely low risk of recurrence [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Intraosseous hemangiomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee) are described in the literature more in women. As long as they are limited to the bone, they are often an asymptomatic random result [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Further growth can cause painful swelling. A typical \u0026ldquo;sunburst\u0026rdquo; phenomenon is shown in the CT [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In the MRI a variable arterio-venous contrast enhancement is described [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Complete resection down to healthy bone is recommended to minimize the recurrence risk [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Meningiomas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026ndash;d) are among the most common benign intracranial tumors. However, about 2% of meningiomas grow ectopic in the bone and infiltrate the adjacent tissue only secondarily [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Typical imaging findings are calcifications, homogeneous contrast enhancement, edema and a dural tail [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Our series includes different WHO grade of meningiomas, which also have significant different infiltrating growth. Adequate preoperative imaging is essential to minimize the intraoperative and postoperative risk for the patient. A complete resection is also recommended for meningiomas. If this is not possible, appropriate adjuvant therapy should be evaluated depending on the histology [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe most common entities of secondary neoplasia are metastasis (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea\u0026ndash;b) of different primary carcinomas. In most cases, they are asymptomatic and stand out as random findings in the regular staging examinations. Patients can develop pain when the periost is infiltrated. By intracranial growth, the patients can also develop neurological deficits. Typical of the imaging are irregular osteolysis with remodeling of the bone, a variable contrast enhancement, and signs of a co-reaction of the surrounding tissue, for example, a perifocal edema [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. A complete resection must be sought and subsequently, an adjuvant treatment should be started depending on the primary carcinoma [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The osteoclastic defects of a plasmacytoma (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed) also fall into the category of secondary neoplasia. Typical are pure osteolysis without remodeling of the bone [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Surgical resection with cover of the bone defect is recommended. In the event of systemic infestation, further treatment of the disease is necessary. In the scenario of a solitary manifestation and complete surgical resection, close-meshed follow-ups are necessary. In this case, further treatment is controversial discussed in the literature [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the group of tumor-like lesions, there are, in particular, histiocytosis (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea\u0026ndash;b), especially eosinophilic granuloma, and metabolic disorders, such as fibrous dysplasia (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec\u0026ndash;e). Histiocytosis (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea\u0026ndash;b) is a group of diseases with an increased proliferation of macrophages. Typical imaging findings are osteolysis with singular bone fragments within the lesion, as a sign of irregular bone destruction. MRI shows a homogeneous contrast enhancement limited to the bone without a co-reaction of the dura or perifocal edema (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The diagnosis can only be secured histologically. After this, a staging should been performed. If the lesion is isolated at the skull, no further therapy is necessary, but for multifocal manifestations, chemotherapy and radiotherapy are recommended [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Another known bone malformation is fibrous dysplasia (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec\u0026ndash;e), which is due to overactivity of osteoclasts and leads to disturbed bone differentiation [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The malformation can affect all bones of the body, including the skull. Patients often complain of severe pain and have swelling or fractures. A distinction is made between the monostotic form (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec\u0026ndash;d), which can be treated by surgical resection and covering the defect [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], from the polyostotic form (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee), in which symptomatic treatment with analgesics and bisphosphonates takes place. In the polyostotic form, only partial removal makes sense if important structures are compressed and patients develop complaints [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. A typical finding in the CT-scan are ground-glass opacities [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn our series, secondary the bone-infiltrating lesions also occurred, such as squamous cell carcinoma and malignant melanoma (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec). These, too, have an osteolytic growth; depending on the stage of the disease, the infiltration can range from the skin to intracranial. Surgical resection and cover of the defect with subsequent systemic adjuvant therapy must be planned [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBased on the imaging, suspicions of the underlying lesion can be obtained (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The limits of a lesion can suggest conclusions about the speed of growth: smooth edges and a homogeneous internal structure mark more of a benign, slowly growing process; irregular edges with inhomogeneous internal structure point, rather, to a malignant, fast-growing process. Also, slowly growing lesions are usually limited to the bone, while fast-growing show an infiltrating growth in adjacent tissue. With the administration of a contrast agent, further conclusions can be drawn about the dignity of the lesion. While reactive or scarring changes in the dura have a linear, homogeneous contrast enhancement, tumor infiltration is often characterized by irregular, inhomogeneous contrast enhancement. If the dura looks distant from the bone and, thus, the epidural space is visible, a dura infiltration is unlikely [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe management of patients with calvarial lesions should be interdisciplinary, as with other oncological diseases. The general practitioner is usually the first contact for the patient, as the lesions are often a random results and there are no complaints. To draw conclusions about the possible entity of the lesion, a targeted image is required [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The suspected diagnoses can be limited and the further procedure planned. In any case, an surgical extraction of a tissue sample is necessary to ensure the diagnosis. If properly planned, the operation is a low-risk procedure without significant morbidity and mortality [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Important imaging aspects are, in particular, the extension of possible infiltration and the course of the large blood vessels, especially intracranially of the sinus. Therefore, we recommend the implementation of a CT and MRI with and without contrast agent. Some lesions can have a similar extension on the bone, but differ significantly in their intracranial spreading (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026ndash;b vs 2c\u0026ndash;d). The medical history, clinical complaints and differential diagnoses must be taken into account together to evaluate the urgency of histological examination. While an underlying carcinoma requires a timely confirmation of a possible metastasis to initiate a targeted adjuvant treatment, in the case of a purely intraosseous lesion with a homogeneous internal structure and without any co-reaction of the adjacent tissue and without any complaints, an initial follow-up observation is also acceptable and surgical care is not urgent. If an operation takes place, a complete resection with cover of the defect must be planned.\u003c/p\u003e "},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThere was no funding for this study\u003c/p\u003e\n\u003ch2\u003eConflict of interest / Competing interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. None of the authors have potential conflicts of interest to be disclosed.\u003c/p\u003e\n\u003ch2\u003eAvailability of data and material\u003c/h2\u003e\n\u003cp\u003eAll data are included in the manuscript.\u003c/p\u003e\n\u003ch2\u003eCode availability\u003c/h2\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003ch2\u003eEthics approval\u003c/h2\u003e\n\u003cp\u003eThis retrospective study was approved by the ethics committee of the Eberhard Karls University Tuebingen (registration no. 028/2019BO2). All procedures performed were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003ch2\u003eConsent to participate and publication\u003c/h2\u003e\n\u003cp\u003eWritten consent was obtained from the patients in order to evaluate and publish the data anonymously\u003c/p\u003e\n\u003ch2\u003e\u0026nbsp;Authors\u0026rsquo; contributions\u003c/h2\u003e\n\u003cp\u003eAll authors listed have made substantial, direct, and intellectual contribution to the work and approved it for publications. INK contributed to data acquisition, analysis, and interpretation of data, statistical analysis, and the writing of the first draft. JMD was responsible for the interpretation of imaging findings, the review and critique of the final manuscript. FE was responsible for the conception and design, as well as the review and critique of the final manuscript. MT has contributed to the interpretation of the data, revising and final approval of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAfghani T, Mansoor H (2018) Types of orbital osteoma - A descriptive analysis. Orbit 37:3-8. doi:10.1080/01676830.2017.1353106\u003c/li\u003e\n\u003cli\u003eBerhouma M, Krichen W, Chamseddine A, Jemel H (2009) [Surgical management of solitary eosinophilic granuloma of the calvaria. Two case reports]. Neurochirurgie 55:555-559. doi:10.1016/j.neuchi.2009.04.001\u003c/li\u003e\n\u003cli\u003eBindal AK, Bindal RK, van Loveren H, Sawaya R (1995) Management of intracranial plasmacytoma. J Neurosurg 83:218-221. doi:10.3171/jns.1995.83.2.0218\u003c/li\u003e\n\u003cli\u003eBowers CA, Taussky P, Couldwell WT (2014) Surgical treatment of craniofacial fibrous dysplasia in adults. Neurosurg Rev 37:47-53. doi:10.1007/s10143-013-0500-z\u003c/li\u003e\n\u003cli\u003eChen TC (2016) Primary Intraosseous Meningioma. Neurosurg Clin N Am 27:189-193. doi:10.1016/j.nec.2015.11.011\u003c/li\u003e\n\u003cli\u003eDong L, Zhang X, Zhang H, Song R, Gu X, He L (2013) Solitary plasmacytoma of the skull: Two case reports. Oncol Lett 5:479-482. doi:10.3892/ol.2012.1046\u003c/li\u003e\n\u003cli\u003eFeller L, Wood NH, Khammissa RA, Lemmer J, Raubenheimer EJ (2009) The nature of fibrous dysplasia. Head Face Med 5:22. doi:10.1186/1746-160X-5-22\u003c/li\u003e\n\u003cli\u003eGarfinkle J, Melancon D, Cortes M, Tampieri D (2011) Imaging pattern of calvarial lesions in adults. Skeletal Radiol 40:1261-1273. doi:10.1007/s00256-010-0971-8\u003c/li\u003e\n\u003cli\u003eGomez CK, Schiffman SR, Bhatt AA (2018) Radiological review of skull lesions. Insights Imaging 9:857-882. doi:10.1007/s13244-018-0643-0\u003c/li\u003e\n\u003cli\u003eGuo Z, Hu K, Zhao B, Bian E, Ni S, Wan J (2017) Osteosarcoma of the skull base: An analysis of 19 cases and literature review. J Clin Neurosci 44:133-142. doi:10.1016/j.jocn.2017.06.014\u003c/li\u003e\n\u003cli\u003eGurbuz MS, Akmil MU, Akar E, Aker FV (2013) Solitary plasmocytoma of the skull. BMJ Case Rep 2013. doi:10.1136/bcr-2013-200379\u003c/li\u003e\n\u003cli\u003eHong B, Hermann EJ, Klein R, Krauss JK, Nakamura M (2010) Surgical resection of osteolytic calvarial lesions: clinicopathological features. Clin Neurol Neurosurg 112:865-869. doi:10.1016/j.clineuro.2010.07.010\u003c/li\u003e\n\u003cli\u003eKotecha R, Angelov L, Barnett GH, Reddy CA, Suh JH, Murphy ES, Neyman G, Chao ST (2014) Calvarial and skull base metastases: expanding the clinical utility of Gamma Knife surgery. J Neurosurg 121 Suppl:91-101. doi:10.3171/2014.7.GKS141272\u003c/li\u003e\n\u003cli\u003eMitra I, Duraiswamy M, Benning J, Joy HM (2016) Imaging of focal calvarial lesions. Clin Radiol 71:389-398. doi:10.1016/j.crad.2015.12.010\u003c/li\u003e\n\u003cli\u003eMohindra S, Kapoor A, Mitra S, Nahar U (2016) Giant primary calvarial hemangioma over torcula: Radiological features and operative nuances. Surg Neurol Int 7:S440-443. doi:10.4103/2152-7806.183544\u003c/li\u003e\n\u003cli\u003eNaama O, Gazzaz M, Akhaddar A, Belhachmi A, Asri A, Elmostarchid B, Elbouzidi A, Kadiri B, Boucetta M (2008) Cavernous hemangioma of the skull: 3 case reports. Surg Neurol 70:654-659. doi:10.1016/j.surneu.2007.05.052\u003c/li\u003e\n\u003cli\u003eOzgiray E, Perumal K, Cinar C, Caliskan KE, Ertan Y, Yurtseven T, Oktar N, Ovul I, Oner K (2016) Management of Calvarial Tumors: A Retrospective Analysis and Literature Review. Turk Neurosurg 26:690-698. doi:10.5137/1019-5149.JTN.12537-15.0\u003c/li\u003e\n\u003cli\u003ePrasanna GV, Katari UK, Vandanapu SK, Reddy MS, Adusumilli HB (2019) Giant Calvarial Cavernous Hemangioma: A Rare Case Report and Review of Literature. Asian J Neurosurg 14:578-580. doi:10.4103/ajns.AJNS_260_18\u003c/li\u003e\n\u003cli\u003eRizea RE, Popescu M, Gheorghita KL, Popescu G, Neamtu MC, Busuioc CJ, Ciurea AV (2018) Neurosurgical rare disease: solitary plasmacytoma of the skull - case report and literature review. Rom J Morphol Embryol 59:367-373\u003c/li\u003e\n\u003cli\u003eSamara A, Nepute J, Lu HC, Perrin RJ, Eldaya RW (2019) Calvarial Langerhans cell histiocytosis in an Adult: Typical imaging findings in an atypical age group. Radiol Case Rep 14:1478-1482. doi:10.1016/j.radcr.2019.09.009\u003c/li\u003e\n\u003cli\u003eSoma PF, Chibbaro S, Makiese O, Marsella M, Diemidio P, Fricia M, Passanisi M, Catania V, Sirago P, Ventura F (2008) Aggressive scalp carcinoma with intracranial extension: a multidisciplinary experience of 25 patients with long-term follow-up. J Clin Neurosci 15:988-992. doi:10.1016/j.jocn.2007.09.014\u003c/li\u003e\n\u003cli\u003eStark AM, Eichmann T, Mehdorn HM (2003) Skull metastases: clinical features, differential diagnosis, and review of the literature. Surg Neurol 60:219-225; discussion 225-216. doi:10.1016/s0090-3019(03)00269-6\u003c/li\u003e\n\u003cli\u003eVital RB, Hamamoto Filho PT, Lapate RL, Martins VZ, de Oliveira Lima F, Romero FR, Zanini MA (2015) Calvarial ectopic meningothelial meningioma. Int J Surg Case Rep 10:69-72. doi:10.1016/j.ijscr.2015.03.033\u003c/li\u003e\n\u003cli\u003eWollina U, Kittner T, Nowak A (2019) Nonmelanoma Skin Cancer with Skull Infiltration and Cranial Involvement. Open Access Maced J Med Sci 7:3030-3033. doi:10.3889/oamjms.2019.416\u003c/li\u003e\n\u003cli\u003eYilmaz A, Musluman M, Aydin Y (2010) Primary osteolytic intraosseous meningioma of the frontal bone. Neurol Neurochir Pol 44:415-418. doi:10.1016/s0028-3843(14)60302-9\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Calvarial lesions, imaging, histiocytosis, meningiomas, metastases","lastPublishedDoi":"10.21203/rs.3.rs-161395/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-161395/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eCalvarial lesions are rare and can present as a variety of different diseases. The lesions can be palpable on the skin, cause local pain and paraesthesia and, depending on the location, neurological deficits can also occur. This research aims to present an overview of typical imaging features as well as neurosurgical management. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eWe examined the charts of patients who underwent surgery on a calvarial lesion in our department between 2004 and 2017 (n=133). Retrospectively, the pre-, intra- and postoperative data were analyzed with morphological and histological findings and compared with each other.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\u003cp\u003ePain, swelling, cosmetically disturbing and neurological deficits were the main complaints. Seventy-seven lesions were limited to the bone, while another 56 lesions showed an infiltrating growth in the adjacent tissue. Depending on the clinical signs and suspected diagnosis, a biopsy, a partial removal or a complete resection was performed. Histiocytosis (n=20), meningiomas (n=20), metastases (n=19) and osteomas (n=16) were the most common lesions. Fibrous dysplasia (n=6) and intraosseous hemangioma (n=9) were less common; other lesions were present only in isolated cases. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eImaging gives a hint, but the diagnosis can be only confirmed by histological examination. The surgical strategy depends on the complaints, location of the lesion and suspected diagnosis. Adjuvant treatment should be initiated according to the histological findings.\u003c/p\u003e","manuscriptTitle":"Calvarial Lesions: Overview of Imaging Features and Neurosurgical Management","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-02-02 18:44:05","doi":"10.21203/rs.3.rs-161395/v1","editorialEvents":[{"type":"communityComments","content":1},{"type":"editorInvitedReview","content":"","date":"2021-02-03T00:00:00+00:00","index":0,"fulltext":""},{"type":"submitted","content":"Neurosurgical Review","date":"2021-01-22T02:41:35+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"neurosurgical-review","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nrev","sideBox":"Learn more about [Neurosurgical Review](https://www.springer.com/journal/10143)","snPcode":"10143","submissionUrl":"https://submission.nature.com/new-submission/10143/3","title":"Neurosurgical Review","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0365abb9-b1f4-4f11-9996-175be8b0c0fb","owner":[],"postedDate":"February 2nd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":2195339,"name":"Neurosurgery"}],"tags":[],"updatedAt":"2021-08-18T19:18:49+00:00","versionOfRecord":{"articleIdentity":"rs-161395","link":"https://doi.org/10.1007/s10143-021-01521-5","journal":{"identity":"neurosurgical-review","isVorOnly":false,"title":"Neurosurgical Review"},"publishedOn":"2021-03-22 19:04:06","publishedOnDateReadable":"March 22nd, 2021"},"versionCreatedAt":"2021-02-02 18:44:05","video":"","vorDoi":"10.1007/s10143-021-01521-5","vorDoiUrl":"https://doi.org/10.1007/s10143-021-01521-5","workflowStages":[]},"version":"v1","identity":"rs-161395","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-161395","identity":"rs-161395","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}