Challenges in diagnosing and interdisciplinary treatment of a patient with Gardner syndrome: a case report

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Carlos Vega, Piera Rosa, Catalina Nestler, María Jose Pinto, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7096806/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Background Gardner syndrome is a phenotypic variant of familial adenomatous polyposis (FAP) with autosomal dominant inheritance, characterized by the diagnostic triad of multiple gastrointestinal polyps, skin and soft tissue tumors, and osteomas, which typically present in the mandible, skull, and long bones. Early detection of these signs is crucial due to the high risk of malignant transformation of colonic polyps before the age of 50. Case presentation: A 17-year-old male patient presented to a dental clinic seeking dental alignment. Clinical examination revealed facial asymmetry, and panoramic radiography showed multiple osteomas, supernumerary teeth, retained deciduous teeth, and impacted permanent teeth. Additionally, the patient had a history of hepatoblastoma at 18 months of age. Given the clinical suspicion of Gardner syndrome, an endoscopic evaluation was performed, revealing more than 40 polyps in the right colon and over 100 sessile polyps in the fundus and body of the stomach. Histopathological analysis reported colonic adenomas with low- and high-grade dysplasia, along with fundic gland polyps. A genetic panel confirmed a heterozygous pathogenic variant in exon 5 of the APC gene: c.509_512del (p.Asp170Valfs*4). Subsequently, first-degree relatives underwent genetic testing, which revealed that the patient’s mother and 21-year-old brother were asymptomatic carriers of the same pathogenic variant, with no extracolonic manifestations. Conclusions This case illustrates how a diagnostic suspicion originating in dental practice, combined with a multidisciplinary approach, can play a decisive role in both the diagnosis and prevention of complications associated with Gardner syndrome. It also underscores the importance of genetic testing in autosomal dominant disorders to identify asymptomatic carriers, enable early diagnosis, and implement timely prophylactic measures in at-risk relatives. Gardner syndrome colonic polyps multidisciplinary approach genetic testing case report Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION One of the genetic disorders that may present with dental anomalies is Gardner syndrome (GS). This condition is considered a phenotypic variant of familial adenomatous polyposis (FAP), inherited in an autosomal dominant pattern and associated with pathogenic variants in the APC gene, located on chromosome 5q21. The prevalence of GS varies across studies, but recent estimates range from 1 in 7,000 to 1 in 30,000 births, affecting males and females equally [ 1 ]. The classical diagnostic triad includes the development of multiple gastrointestinal polyps, skin and soft tissue tumors, and osteomas [ 2 ]. Colonic polyps are typically numerous, distributed from the cecum to the rectum, and carry a high risk of malignant transformation before the age of 50. Consequently, prophylactic colectomy or proctocolectomy is often recommended. According to Weiss, patients with GS may develop colorectal cancer before the age of 35, with cancer being one of the leading causes of death in this population [ 3 ]. In addition, there is an increased risk of developing other neoplasms, such as hepatoblastoma, duodenal carcinoma near the hepatopancreatic ampulla, pancreatic cancer, papillary or follicular thyroid cancer, and medulloblastomas in the central nervous system [ 4 ]. Moreover, Gardner syndrome can present clinical signs at the craniofacial level. These craniofacial manifestations vary among patients and may appear as early as 2 months of age and up to 70 years, although they are most commonly observed during adolescence. One of the frequent findings in GS is the presence of osteomas, which are asymptomatic, slow-growing bone lesions that typically develop in the mandible, but may also appear in the maxilla or in relation to the frontal, maxillary, and ethmoidal sinuses [ 2 ]. In addition to osteomas, various dental anomalies may also be present, including tooth agenesis, ectopic eruption, persistence of primary teeth, tooth retention, hypercementosis, odontomas, supernumerary teeth, and dental fusions [ 5 ]. Other findings include lipomas, epidermoid cysts, desmoid tumors, pilomatricomas (≥ 6 lesions), adrenal adenomas, and congenital hypertrophy of the retinal pigment epithelium [ 1 , 5 ]. Given the hereditary nature of the syndrome, patients suspected of having Gardner syndrome should undergo genetic testing to identify the presence of a mutation in the APC gene. If a mutation is detected, its location should also be determined, as multiple studies have demonstrated a correlation between the mutation site and the patient’s phenotype, which can help predict potential associated risks [ 6 , 7 ]. For example, mutations located between codons 157 and 1595 are associated with a classical polyposis phenotype (with > 100 and < 1000 polyps) by the age of 30, whereas mutations at the 5' end of codon 157, between codons 213–412, and at the 3' end beyond codon 1595 are associated with an attenuated polyposis phenotype (< 100 polyps) that typically manifests at later ages (around 52 years) [ 8 , 9 ]. Various extracolonic manifestations, such as osteomas, have been correlated with mutations located between codons 767 and 1513, while hepatoblastomas have been linked to mutations between codons 140 and 1578 [ 10 , 11 ]. In addition, a increased risk of developing desmoid tumors has been associated with mutations between codons 1310 and 2011 [ 12 ]. This study describes the clinical case of a patient whose maxillofacial presentation enabled an early diagnosis of Gardner syndrome, which also led to the identification of carrier family members. This highlights the fundamental role of the dentist in the early detection of this hereditary condition. CASE PRESENTATION A 17-year-old male patient, healthy, with a history of hepatoblastoma and hepatectomy at 18 months of age, presented to the Orthodontics Department at Clínica Universidad de los Andes for evaluation. Extraoral clinical examination revealed noticeable facial asymmetry in the lower right mandibular third, which became more prominent upon mouth opening. On palpation, a firm, hard-consistency mass was detected in the region corresponding to the right mandibular ramus (Fig. 1 ). Intraoral examination showed mandibular deviation to the right, with the mandibular midline shifted to the same side. Additionally, a crossbite involving tooth 1.6 and persistence of tooth 7.3 were noted (Fig. 2 ). Imaging assessment using panoramic radiography and cone beam computed tomography (CBCT) revealed the following findings: absence of tooth 1.8, impaction of 2.8, partial impaction of 4.8, intraosseous development of 3.8, a supernumerary tooth between the roots of teeth 2.3 and 2.4, and, in relation to tooth 2.6, a retained 3.3. Irregular sclerotic areas were also observed at the apical region of teeth 4.6, 4.5, 4.4, 4.3, and 3.6, compatible with endosteal osteomas. Additionally, a pedunculated hyperdense lesion with irregular shape and multiple rounded contours, consistent with an osteoma, was identified in the middle and upper thirds of the right mandibular ramus. Osteomas were also noted in the ascending process of the right maxilla, distal to the aforementioned mass, and in the anterior ethmoidal region (Fig. 3 ). Given the diagnostic suspicion of Gardner syndrome, the patient was referred to the Department of Gastroenterology. Colonoscopy revealed approximately 40 polyps, mainly located in the right colon, measuring 4–8 mm. Upper gastrointestinal endoscopy showed more than 100 sessile gastric polyps, ranging from 2–8 mm, located in the fundus and body of the stomach. Histopathological examination reported tubular colonic adenomas with low- and high-grade dysplasia, along with fundic gland polyps in the stomach. Based on these findings and due to the low number of rectal polyps, the patient underwent a prophylactic total colectomy with laparoscopic ileorectal anastomosis, which was performed uneventfully and with good postoperative recovery. The surgical specimen measured 60 cm and contained a total of 56 polyps, including 51 tubular adenomas with moderate dysplasia and 5 serrated adenomas. Subsequently, the patient was enrolled in the hereditary oncology program at our institution, where counseling and genetic testing are performed. Regarding family history, the mother has been diagnosed with systemic lupus erythematosus and Hashimoto's thyroiditis. The father does not present any systemic diseases, nor do the maternal and paternal uncles, or the patient's four siblings. On the maternal side, oncological history includes a great-grandfather who died of colon cancer at the age of 42, a grandfather diagnosed with a pancreatic carcinoid tumor at the age of 67, a great-aunt with breast cancer at the ages of 52 and 66, another great-aunt with osteosarcoma at age 67, and a great-grandmother with leukemia. On the paternal side, there is a great-uncle diagnosed with prostate cancer (Fig. 4 ). The genetic study was performed using a panel of 110 genes, including those that predispose to colorectal cancer and colonic polyposis, identifying a pathogenic variant in exon 5 of the APC gene corresponding to a four-nucleotide deletion c.509_512, which results in a frameshift and a truncated protein p.Asp170Valfs*4 (Fig. 5 ). Subsequently, the patient’s first-degree relatives, including parents and siblings, were evaluated to rule out a de novo mutation, given the absence of relevant family history suggestive of a genetic syndrome. These results identified that the pathogenic APC variant was inherited from the maternal side, as the mother carries this genetic alteration, as does her 21-year-old son. Table 1 summarizes the clinical characteristics of the carrier family members, highlighting the significant difference in the phenotypic expression of gastrointestinal polyps and extracolonic manifestations among them. The mother was diagnosed with colonic polyposis with more than 100 polyps at the age of 51, while the 21-year-old brother showed only 4 polyps in the right colon. This finding confirms the hereditary nature of the syndrome in this case and underscores the importance of family screening in early diagnosis and proper follow-up to prevent neoplasms associated with the syndrome. Table 1 Clinical manifestations associated with the APC gene in the family group. Age Sex Extracolonic manifestations Gastrointestinal manifestations Index case 18 years M Mandibular osteoma Gastric polyposis (> 100 polyps), colonic polyposis (> 50 polyps) Mother 51 years F Fibroma in right arm Colonic polyposis (> 100 polyps) Brother 21 years M Thyroid nodule Colonic polyps (< 10 polyps) M: male, F: female One year after surgery, the maxillofacial surgery team performed a resection of the mandibular osteomas, extraction of the supernumerary teeth and third molars and the fenestration of tooth 3.3 All these procedures were carried out in a surgical operating room. Currently, the patient is under periodic clinical and radiographic monitoring, as well as annual endoscopies and rectoscopies, to rule out other complications related to this disease. DISCUSSION The presence of three or more maxillary osteomas in a patient is highly suggestive of GS, which should prompt the clinician to investigate the family history, with particular emphasis on a history of colonic polyposis and/or colorectal cancer [ 13 , 14 ]. It is important to note that approximately 25% of cases are de novo, meaning they are the first case in their line of descent [ 4 ], which was considered a possibility in our patient, as no relevant family history was initially reported. In addition, a significant clinical antecedent was that the patient underwent surgery for a hepatoblastoma at the age of 1 year and 6 months. Although rare, this neoplasm has been associated with mutations in the APC gene, the same gene involved in GS. Various clinical guidelines recognize hepatoblastoma as a possible early extracolonic manifestation in patients with mutations in this gene [ 15 ]; therefore, this history could have served as an early warning sign to perform genetic testing. For this reason, the role of various health specialties, including pediatrics and dentistry, which manage the patient from early childhood, becomes relevant as these clinical findings allow for timely referral. According to Weiss et al., when the pathogenic variant has already been identified in the family, it is recommended to perform genetic testing starting at 10–12 years of age, and for those who are carriers, to begin surveillance between the ages of 10 and 15 through annual endoscopies and colonoscopies in order to monitor the growth and development of polyps and to detect any progression toward malignant lesions at an early stage [ 3 ]. This surveillance approach is supported by international clinical guidelines and has proven to be key in the prevention of colorectal cancer in patients with mutations in the APC gene. In addition, if 30 or more polyps are present, depending on their size, location, and histology, risk-reducing surgery such as total colectomy or proctocolectomy may be recommended. In this case, a total colectomy was performed since our patient presented high-risk criteria with adenomas with high-grade dysplasia, exponential growth, and size > 5 mm [ 16 , 15 ]. The genetic study of our index case demonstrated a pathogenic variant in exon 5 of the APC gene, identified as c.509_512del, which produces a truncated protein p.Asp170ValfsTer4. Given the positive result, the immediate family was tested, revealing that the mother and older brother also carried the mutation, despite both being asymptomatic at that time and without orofacial manifestations. Although our index case presented with a very aggressive form of the disease associated with GS, the mother and brother exhibited an attenuated phenotype. All three patients carry the pathogenic variant at codon 170, which, according to the genotype-phenotype correlation, could manifest as either classical or severe polyposis, possibly explaining the differences observed in this family. These phenotypic variations among individuals from the same family and between families with the identical pathogenic APC variant have been previously described, which is why each case of Gardner syndrome must be managed individually [ 9 , 17 ]. Table 2 presents a selection of case reports published between 2020 and 2025 in the PubMed, SciELO, and EBSCO databases, in which the diagnosis of Gardner’s syndrome was made based on oral or maxillofacial manifestations. Upon analyzing the selected cases, it was observed that osteomas in the maxillomandibular region were present in 8 of the 9 cases analyzed and involved the maxillomandibular area; in the remaining case, the osteoma was located in other bony structures of the skull and face. Likewise, 8 articles reported dental anomalies, including supernumerary teeth, impacted teeth, odontomas, and retained deciduous teeth [ 18 – 26 ]. These findings are consistent with what is reported in the literature, where dental anomalies are present in 30–75% of patients with GS, and osteomas in 68–82% [ 27 , 28 ]. Although genetic testing was conducted in only 4 of the cases, the absence of genetic confirmation was attributed to factors such as economic constraints and limited time available to complete the genetic study. Finally, the age of the patients at the time of diagnosis varied, ranging from 11 to 59 years old. This highlights the importance of being alert to oral signs compatible with GS in patients of any age. Table 2 Case Reports of Gardner Syndrome Diagnosed Based on Oral or Maxillofacial Manifestations, Published in PubMed, SciELO, and EBSCO between 2020 and 2025. Author and year Sex of the patient Age of the patient Family history Genetic Testing Osteoma Location Dental Anomalies Soft Tissue Manifestations Gastrointestinal Manifestations Antal et al., 2024 F 14 years Yes Yes Mandible and maxilla Odontoma, impacted and retained teeth Epidermoid cysts N/R Olusegun et al., 2024 M 41 years No No Mandible Odontoma, semi-include, retained, supernumerary and deciduous teeth Epidermoid cysts and desmoid tumors Multiple polyps with various grades of dysplasia Shetty et al., 2023 M 59 years No No Mandible, maxilla, frontal bone and paranasal sinuses Impacted teeth and persistence of deciduous teeth. Sebaceous cyst on scalp and nodules on forehead Polyp located in the colon McKenzie et al., 2023 M 50 years Yes No Mandible Partially erupted, retained, and deciduous teeth; idiopathic osteosclerosis Epidermoid cysts in temporal and malar region Rectal cancer Lucamba et al., 2023 M 11 years No No Mandible and maxilla Non-erupted teeth N/R Intestinal polyps Kozan et al., 2022 M 16 years No Yes Mandible N/R Subcutaneous lipoma in lumbar región Intermittent diarrhea and abdominal pain; Polyps in the rectum and approx. 30–35 polyps in other sections of the colon M 16 years Yes Yes Mandible N/R Fibrolipomatous lesions in neck and scapula Polyps in the rectum and approx. 20–25 polyps in other segments of the colon. Tiol-Carrillo et al ., 2021 M 42 years No N/R Mandible and maxilla Persistence of deciduous teeth, retention of permanent teeth, and supernumerary teeth Epidermoid cysts N/R Antohi et al ., 2021 F 16 years Yes Yes Mandible and craniofacial bones Impacted teeth N/R Multiple colonic polyps (approximately 50–70) M 12 years Yes Yes Mandible, temporal and frontal bone Supernumerary and impacted teeth and hypercementosis Chest lipoma Colonic polyps Saito et al ., 2021 M 29 years Yes Yes Cranial and facial bones Odontoma, retained and impacted teeth, osteosclerosis of maxilla and mandible N/R Multiple polyps in stomach and colon M: male; F: female; N/R: not reported; Approx: approximately. In addition, a targeted search was conducted to identify previous reports of Chilean patients with familial adenomatous polyposis presenting with orofacial manifestations. One article was found, published by Urzúa-Orellana et al. in 2018, which describes a Chilean family with a clinical diagnosis of familial adenomatous polyposis, in which odontoma, osteomas, and various dental malformations were observed during the dental clinical examination. However, this report does not include a genetic study [ 29 ]. On the other hand, a search was conducted to identify previous reports of Chilean patients with familial adenomatous polyposis presenting with orofacial manifestations. An article published by Urzúa-Orellana et al. in 2018 was found, describing a Chilean family with a clinical diagnosis of familial adenomatous polyposis, in which odontoma, osteomas, and various dental malformations were observed during the dental clinical examination. However, this report does not include genetic testing [ 18 ]. It should be noted that this case represents the first to be referred by a dentist at Clínica de los Andes, Santiago, Chile. Despite the low incidence of Gardner syndrome, its clinical and radiographic features are well defined. In this context, panoramic radiography and a routine examination in dental practice, is key in patients with Gardner syndrome. In particular, regarding the management of mandibular osteomas, it is usually conservative when they are asymptomatic. However, in cases like ours, where facial aesthetics are compromised and this could have psychological repercussions for the patient, surgical intervention is considered the most appropriate alternative. Therefore, it is recommended to individualize the treatment, taking into account factors such as the size and location of the bone lesion [ 19 ]. It is essential for the dentist to recognize the clinical signs of systemic diseases with craniofacial manifestations, as they may be the first indication of a diagnostic suspicion and thus allow for timely referral. Adequate knowledge of these diseases not only has a positive impact on the patient’s clinical outcome but also benefits their family members by identifying possible hereditary cases, as was the case with our patient’s family. Since GS is an autosomal dominant disease, the evaluation of direct relatives through genetic testing and early colonoscopies is highly relevant to identify asymptomatic carriers and significantly reduce the mortality associated with this syndrome. In case of any diagnostic uncertainty, it is essential to turn to a multidisciplinary team that can address the needs of the patient and their family in a comprehensive and effective manner. CONCLUSION Craniofacial manifestations of GS are varied, developing mainly during puberty and generally preceding the appearance of gastrointestinal polyps. These manifestations are primarily associated with the presence of osteomas and dental anomalies. In this case, the initial dental diagnosis not only confirmed the disease in the patient but also led to the identification of the mutation in family members through genetic testing, which resulted in timely treatment. These findings reinforce the importance of a multidisciplinary approach and family evaluation in GS, highlighting the role of the dentist in early detection and referral. Abbreviations GS: Gardner Syndrome. FAP: Familial Adenomatous Polyposis. APC: Adenomatous Polyposis Coli gene. CBCT: Cone Beam Computed Tomography. Declarations Ethics approval and consent to participate: This case report was approved by the Scientific Ethics Committee of Universidad de los Andes. Reference number: CEC2023093. Consent for publication: A signed informed consent form for publication was obtained directly from the patient. Although the patient was 17 years old when clinical treatment initially began, consent for publication was obtained later, when the patient was 21 years old and had already reached the age of majority in Chile. At that time, he was fully capable of understanding the nature and purpose of this case report; therefore, consent from a legal guardian was not required. In addition, at the beginning of treatment, when the patient was still a minor, informed consent for all clinical procedures was provided by the patient's mother, and assent was obtained from the patient himself. Availability of data and materials: All data generated or analysed during this study are included in this published article. The datasets used and/or analysed are available from the corresponding author on reasonable request. Competing Interests: The authors declare no competing interest. Funding: There was no funding for this case report. Author’s Contributions: Concept and design: CV, CN, PR. Administrative support: MS, CN, PR. Provision of study materials or patients: CV, KA, FR, FL. Data collection and assembly: CV, KA, CN, PR, IC, FL, DO. Data analysis and interpretation: CV, CN, PR, MP, KA, JJ, FL. Manuscript writing and final approval: CV, KA, CN, PR, MP, JJ, FL, DO. Acknowledgement: We thank the patient of this study for his contribution to scientific knowledge and the clinic of Universidad de Los Andes for the authorization and commitment. Clinical trial number: Not applicable. Use of AI: During this preparation of the work, the authors use ChatGPT 4.0 only for the translation and edition of the document. The authors reviewed and edited the content as needed and take full responsibility for the content of the publication. References Charifa A, Jamil RT, Sathe NC, Zhang X. Gardner Syndrome. En: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025. Available from: http://www.ncbi.nlm.nih.gov/books/NBK482342/ Gorling R, Cohen M, Hennekam R. 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Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 04 Mar, 2026 Reviewers agreed at journal 25 Feb, 2026 Reviews received at journal 22 Feb, 2026 Reviewers agreed at journal 20 Feb, 2026 Reviewers agreed at journal 20 Feb, 2026 Reviewers agreed at journal 13 Feb, 2026 Reviewers agreed at journal 26 Sep, 2025 Reviewers invited by journal 26 Sep, 2025 Editor invited by journal 09 Sep, 2025 Editor assigned by journal 22 Jul, 2025 Submission checks completed at journal 21 Jul, 2025 First submitted to journal 21 Jul, 2025 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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Carlos Vega","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvUlEQVRIiWNgGAWjYPACGyBmbDxAipY0kJYGkrQcBpPEaeGfkXz4xc8d5+3Wth8G2lJjE01Qi8SNtDTL3jO3k7edSQRqOZaW20BIiwHPGTMD3rbbyWYHgFoYGw4To+X8N8O/beeSzc4/JFYLew/zY962A3ZmN4i1ReJ4mxmz7JnkBLMbQFsSiPELfzPz449vd9jZm51Pf/jgQ40NYS1AwCbB2MCQCFaZQIRyEGD+ANRiT6TiUTAKRsEoGIkAAGh/SV5uoqqKAAAAAElFTkSuQmCC","orcid":"","institution":"Universidad de Los Andes, Chile","correspondingAuthor":true,"prefix":"","firstName":"P.","middleName":"Carlos","lastName":"Vega","suffix":""},{"id":525270540,"identity":"8ecb586d-ff07-424d-8275-ba8913d142e4","order_by":1,"name":"Piera Rosa","email":"","orcid":"","institution":"Universidad de Los Andes, Chile","correspondingAuthor":false,"prefix":"","firstName":"Piera","middleName":"","lastName":"Rosa","suffix":""},{"id":525270541,"identity":"0f89f956-69db-493d-a482-765a75f1f612","order_by":2,"name":"Catalina 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14:19:51","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":115658,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/37ad1db9f95963eba73a7252.png"},{"id":93842001,"identity":"ea5962e9-aa5d-4d54-9ff5-7f464e9b95e5","added_by":"auto","created_at":"2025-10-18 14:11:51","extension":"xml","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":86934,"visible":true,"origin":"","legend":"","description":"","filename":"0c2fccda733c4d1aa4c29c24b81b81d51structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/f1e3234230400b3a7ec0b6d5.xml"},{"id":93842581,"identity":"7383f359-85d2-4455-9919-f869df3e31c5","added_by":"auto","created_at":"2025-10-18 14:19:51","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":95354,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/0103e28dfc43e82953c01ab6.html"},{"id":93842575,"identity":"f10326a0-3316-4003-8af0-950c08e78a43","added_by":"auto","created_at":"2025-10-18 14:19:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2278505,"visible":true,"origin":"","legend":"\u003cp\u003eExtraoral photographs.\u003cstrong\u003e\u003cbr\u003e\n \u003c/strong\u003e\u003cem\u003eArrows: indicate facial asymmetry on the right side compared to the left, accentuated upon mouth opening.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/ff2d44edce574024b222c938.png"},{"id":93841984,"identity":"5db834a8-4c3e-4e14-b2cb-122fb63cef73","added_by":"auto","created_at":"2025-10-18 14:11:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":688972,"visible":true,"origin":"","legend":"\u003cp\u003eIntraoral photographs.\u003cstrong\u003e\u003cbr\u003e\n \u003c/strong\u003e\u003cem\u003eA: Frontal view. B: Right lateral view.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/a491560bc3e6ab0e0250fd52.png"},{"id":93842577,"identity":"ecb4b2ff-079e-486b-9491-a1c5d0309c29","added_by":"auto","created_at":"2025-10-18 14:19:51","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":381169,"visible":true,"origin":"","legend":"\u003cp\u003ePanoramic radiograph.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eA: Osteoma in the right mandibular ramus. B: Supernumerary tooth. C: Endosteal osteomas. D: Impacted tooth 3.3 / persistence of tooth 7.3.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.3.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/ae672838f6cbfc7a9e4e9018.png"},{"id":93843540,"identity":"fadae483-ebd4-458c-bfbd-ef7f400d6f87","added_by":"auto","created_at":"2025-10-18 14:27:51","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":120021,"visible":true,"origin":"","legend":"\u003cp\u003ePedigree.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe arrow indicates the proband, who presented with a hepatoblastoma at one year and six months of age. A family history of maternal cases includes colon cancer, leukemia, pancreatic cancer, breast cancer, and osteosarcoma. On the paternal side, there is a recorded case of prostate cancer.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/623c3ebedb3254a047fc3285.png"},{"id":93842576,"identity":"60f2cbe0-9108-4ff3-bc4b-879f83673c79","added_by":"auto","created_at":"2025-10-18 14:19:51","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":300610,"visible":true,"origin":"","legend":"\u003cp\u003eAPC genetic variant.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSequencing results showing the pathogenic variant in the APC gene identified in our patient, corresponding to a deletion c.509_512, which results in a truncated protein p.Asp170Valfs*4.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.5.png","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/07f33edc95a9f5193bdb256b.png"},{"id":93843725,"identity":"2a95732d-5030-4ca9-9724-da5f19a9105b","added_by":"auto","created_at":"2025-10-18 14:35:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4397612,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7096806/v1/5f8690f1-a936-463b-943d-034afcfe13e8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Challenges in diagnosing and interdisciplinary treatment of a patient with Gardner syndrome: a case report","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eOne of the genetic disorders that may present with dental anomalies is Gardner syndrome (GS). This condition is considered a phenotypic variant of familial adenomatous polyposis (FAP), inherited in an autosomal dominant pattern and associated with pathogenic variants in the APC gene, located on chromosome 5q21. The prevalence of GS varies across studies, but recent estimates range from 1 in 7,000 to 1 in 30,000 births, affecting males and females equally [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The classical diagnostic triad includes the development of multiple gastrointestinal polyps, skin and soft tissue tumors, and osteomas [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Colonic polyps are typically numerous, distributed from the cecum to the rectum, and carry a high risk of malignant transformation before the age of 50. Consequently, prophylactic colectomy or proctocolectomy is often recommended. According to Weiss, patients with GS may develop colorectal cancer before the age of 35, with cancer being one of the leading causes of death in this population [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn addition, there is an increased risk of developing other neoplasms, such as hepatoblastoma, duodenal carcinoma near the hepatopancreatic ampulla, pancreatic cancer, papillary or follicular thyroid cancer, and medulloblastomas in the central nervous system [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMoreover, Gardner syndrome can present clinical signs at the craniofacial level. These craniofacial manifestations vary among patients and may appear as early as 2 months of age and up to 70 years, although they are most commonly observed during adolescence. One of the frequent findings in GS is the presence of osteomas, which are asymptomatic, slow-growing bone lesions that typically develop in the mandible, but may also appear in the maxilla or in relation to the frontal, maxillary, and ethmoidal sinuses [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In addition to osteomas, various dental anomalies may also be present, including tooth agenesis, ectopic eruption, persistence of primary teeth, tooth retention, hypercementosis, odontomas, supernumerary teeth, and dental fusions [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Other findings include lipomas, epidermoid cysts, desmoid tumors, pilomatricomas (≥ 6 lesions), adrenal adenomas, and congenital hypertrophy of the retinal pigment epithelium [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eGiven the hereditary nature of the syndrome, patients suspected of having Gardner syndrome should undergo genetic testing to identify the presence of a mutation in the \u003cem\u003eAPC\u003c/em\u003e gene. If a mutation is detected, its location should also be determined, as multiple studies have demonstrated a correlation between the mutation site and the patient’s phenotype, which can help predict potential associated risks [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. For example, mutations located between codons 157 and 1595 are associated with a classical polyposis phenotype (with \u0026gt; 100 and \u0026lt; 1000 polyps) by the age of 30, whereas mutations at the 5' end of codon 157, between codons 213–412, and at the 3' end beyond codon 1595 are associated with an attenuated polyposis phenotype (\u0026lt; 100 polyps) that typically manifests at later ages (around 52 years) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Various extracolonic manifestations, such as osteomas, have been correlated with mutations located between codons 767 and 1513, while hepatoblastomas have been linked to mutations between codons 140 and 1578 [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In addition, a increased risk of developing desmoid tumors has been associated with mutations between codons 1310 and 2011 [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis study describes the clinical case of a patient whose maxillofacial presentation enabled an early diagnosis of Gardner syndrome, which also led to the identification of carrier family members. This highlights the fundamental role of the dentist in the early detection of this hereditary condition.\u003c/p\u003e"},{"header":"CASE PRESENTATION","content":"\u003cp\u003eA 17-year-old male patient, healthy, with a history of hepatoblastoma and hepatectomy at 18 months of age, presented to the Orthodontics Department at Clínica Universidad de los Andes for evaluation. Extraoral clinical examination revealed noticeable facial asymmetry in the lower right mandibular third, which became more prominent upon mouth opening. On palpation, a firm, hard-consistency mass was detected in the region corresponding to the right mandibular ramus (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Intraoral examination showed mandibular deviation to the right, with the mandibular midline shifted to the same side. Additionally, a crossbite involving tooth 1.6 and persistence of tooth 7.3 were noted (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eImaging assessment using panoramic radiography and cone beam computed tomography (CBCT) revealed the following findings: absence of tooth 1.8, impaction of 2.8, partial impaction of 4.8, intraosseous development of 3.8, a supernumerary tooth between the roots of teeth 2.3 and 2.4, and, in relation to tooth 2.6, a retained 3.3. Irregular sclerotic areas were also observed at the apical region of teeth 4.6, 4.5, 4.4, 4.3, and 3.6, compatible with endosteal osteomas. Additionally, a pedunculated hyperdense lesion with irregular shape and multiple rounded contours, consistent with an osteoma, was identified in the middle and upper thirds of the right mandibular ramus. Osteomas were also noted in the ascending process of the right maxilla, distal to the aforementioned mass, and in the anterior ethmoidal region (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGiven the diagnostic suspicion of Gardner syndrome, the patient was referred to the Department of Gastroenterology. Colonoscopy revealed approximately 40 polyps, mainly located in the right colon, measuring 4–8 mm. Upper gastrointestinal endoscopy showed more than 100 sessile gastric polyps, ranging from 2–8 mm, located in the fundus and body of the stomach. Histopathological examination reported tubular colonic adenomas with low- and high-grade dysplasia, along with fundic gland polyps in the stomach. Based on these findings and due to the low number of rectal polyps, the patient underwent a prophylactic total colectomy with laparoscopic ileorectal anastomosis, which was performed uneventfully and with good postoperative recovery. The surgical specimen measured 60 cm and contained a total of 56 polyps, including 51 tubular adenomas with moderate dysplasia and 5 serrated adenomas.\u003c/p\u003e\u003cp\u003eSubsequently, the patient was enrolled in the hereditary oncology program at our institution, where counseling and genetic testing are performed. Regarding family history, the mother has been diagnosed with systemic lupus erythematosus and Hashimoto's thyroiditis. The father does not present any systemic diseases, nor do the maternal and paternal uncles, or the patient's four siblings. On the maternal side, oncological history includes a great-grandfather who died of colon cancer at the age of 42, a grandfather diagnosed with a pancreatic carcinoid tumor at the age of 67, a great-aunt with breast cancer at the ages of 52 and 66, another great-aunt with osteosarcoma at age 67, and a great-grandmother with leukemia. On the paternal side, there is a great-uncle diagnosed with prostate cancer (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe genetic study was performed using a panel of 110 genes, including those that predispose to colorectal cancer and colonic polyposis, identifying a pathogenic variant in exon 5 of the APC gene corresponding to a four-nucleotide deletion c.509_512, which results in a frameshift and a truncated protein p.Asp170Valfs*4 (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Subsequently, the patient’s first-degree relatives, including parents and siblings, were evaluated to rule out a de novo mutation, given the absence of relevant family history suggestive of a genetic syndrome. These results identified that the pathogenic APC variant was inherited from the maternal side, as the mother carries this genetic alteration, as does her 21-year-old son. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the clinical characteristics of the carrier family members, highlighting the significant difference in the phenotypic expression of gastrointestinal polyps and extracolonic manifestations among them. The mother was diagnosed with colonic polyposis with more than 100 polyps at the age of 51, while the 21-year-old brother showed only 4 polyps in the right colon. This finding confirms the hereditary nature of the syndrome in this case and underscores the importance of family screening in early diagnosis and proper follow-up to prevent neoplasms associated with the syndrome.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cdiv class=\"gridtable\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical manifestations associated with the APC gene in the family group.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSex\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eExtracolonic manifestations\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGastrointestinal manifestations\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eIndex case\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMandibular osteoma\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGastric polyposis (\u0026gt; 100 polyps), colonic polyposis (\u0026gt; 50 polyps)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMother\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFibroma in right arm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eColonic polyposis (\u0026gt; 100 polyps)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eBrother\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eThyroid nodule\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eColonic polyps (\u0026lt; 10 polyps)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eM: male, F: female\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cp\u003eOne year after surgery, the maxillofacial surgery team performed a resection of the mandibular osteomas, extraction of the supernumerary teeth and third molars and the fenestration of tooth 3.3 All these procedures were carried out in a surgical operating room.\u003c/p\u003e\u003cp\u003eCurrently, the patient is under periodic clinical and radiographic monitoring, as well as annual endoscopies and rectoscopies, to rule out other complications related to this disease.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe presence of three or more maxillary osteomas in a patient is highly suggestive of GS, which should prompt the clinician to investigate the family history, with particular emphasis on a history of colonic polyposis and/or colorectal cancer [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. It is important to note that approximately 25% of cases are de novo, meaning they are the first case in their line of descent [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], which was considered a possibility in our patient, as no relevant family history was initially reported. In addition, a significant clinical antecedent was that the patient underwent surgery for a hepatoblastoma at the age of 1 year and 6 months. Although rare, this neoplasm has been associated with mutations in the APC gene, the same gene involved in GS. Various clinical guidelines recognize hepatoblastoma as a possible early extracolonic manifestation in patients with mutations in this gene [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]; therefore, this history could have served as an early warning sign to perform genetic testing. For this reason, the role of various health specialties, including pediatrics and dentistry, which manage the patient from early childhood, becomes relevant as these clinical findings allow for timely referral.\u003c/p\u003e\u003cp\u003eAccording to Weiss et al., when the pathogenic variant has already been identified in the family, it is recommended to perform genetic testing starting at 10\u0026ndash;12 years of age, and for those who are carriers, to begin surveillance between the ages of 10 and 15 through annual endoscopies and colonoscopies in order to monitor the growth and development of polyps and to detect any progression toward malignant lesions at an early stage [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. This surveillance approach is supported by international clinical guidelines and has proven to be key in the prevention of colorectal cancer in patients with mutations in the APC gene. In addition, if 30 or more polyps are present, depending on their size, location, and histology, risk-reducing surgery such as total colectomy or proctocolectomy may be recommended. In this case, a total colectomy was performed since our patient presented high-risk criteria with adenomas with high-grade dysplasia, exponential growth, and size\u0026thinsp;\u0026gt;\u0026thinsp;5 mm [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe genetic study of our index case demonstrated a pathogenic variant in exon 5 of the APC gene, identified as c.509_512del, which produces a truncated protein p.Asp170ValfsTer4. Given the positive result, the immediate family was tested, revealing that the mother and older brother also carried the mutation, despite both being asymptomatic at that time and without orofacial manifestations. Although our index case presented with a very aggressive form of the disease associated with GS, the mother and brother exhibited an attenuated phenotype.\u003c/p\u003e\u003cp\u003eAll three patients carry the pathogenic variant at codon 170, which, according to the genotype-phenotype correlation, could manifest as either classical or severe polyposis, possibly explaining the differences observed in this family. These phenotypic variations among individuals from the same family and between families with the identical pathogenic APC variant have been previously described, which is why each case of Gardner syndrome must be managed individually [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents a selection of case reports published between 2020 and 2025 in the PubMed, SciELO, and EBSCO databases, in which the diagnosis of Gardner\u0026rsquo;s syndrome was made based on oral or maxillofacial manifestations. Upon analyzing the selected cases, it was observed that osteomas in the maxillomandibular region were present in 8 of the 9 cases analyzed and involved the maxillomandibular area; in the remaining case, the osteoma was located in other bony structures of the skull and face. Likewise, 8 articles reported dental anomalies, including supernumerary teeth, impacted teeth, odontomas, and retained deciduous teeth [\u003cspan additionalcitationids=\"CR19 CR20 CR21 CR22 CR23 CR24 CR25\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. These findings are consistent with what is reported in the literature, where dental anomalies are present in 30\u0026ndash;75% of patients with GS, and osteomas in 68\u0026ndash;82% [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Although genetic testing was conducted in only 4 of the cases, the absence of genetic confirmation was attributed to factors such as economic constraints and limited time available to complete the genetic study. Finally, the age of the patients at the time of diagnosis varied, ranging from 11 to 59 years old. This highlights the importance of being alert to oral signs compatible with GS in patients of any age.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCase Reports of Gardner Syndrome Diagnosed Based on Oral or Maxillofacial Manifestations, Published in PubMed, SciELO, and EBSCO between 2020 and 2025.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAuthor and year\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSex of the patient\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAge of the patient\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFamily history\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGenetic Testing\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eOsteoma Location\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eDental Anomalies\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSoft Tissue Manifestations\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eGastrointestinal Manifestations\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAntal et al., 2024\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible and maxilla\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eOdontoma, impacted and retained teeth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eEpidermoid cysts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eOlusegun et al., 2024\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eOdontoma, semi-include, retained, supernumerary and deciduous teeth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eEpidermoid cysts and desmoid tumors\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eMultiple polyps with various grades of dysplasia\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eShetty et al., 2023\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e59 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible, maxilla, frontal bone and paranasal sinuses\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImpacted teeth and persistence of deciduous teeth.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSebaceous cyst on scalp and nodules on forehead\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003ePolyp located in the colon\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMcKenzie et al., 2023\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ePartially erupted, retained, and deciduous teeth; idiopathic osteosclerosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eEpidermoid cysts in temporal and malar region\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eRectal cancer\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eLucamba et al., 2023\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible and maxilla\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNon-erupted teeth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eIntestinal polyps\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eKozan et al., 2022\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSubcutaneous lipoma in lumbar regi\u0026oacute;n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eIntermittent diarrhea and abdominal pain; Polyps in the rectum and approx. 30\u0026ndash;35 polyps in other sections of the colon\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eFibrolipomatous lesions in neck and scapula\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003ePolyps in the rectum and approx. 20\u0026ndash;25 polyps in other segments of the colon.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTiol-Carrillo\u003c/b\u003e \u003cb\u003eet al\u003c/b\u003e., \u003cb\u003e2021\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e42 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible and maxilla\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ePersistence of deciduous teeth, retention of permanent teeth, and supernumerary teeth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eEpidermoid cysts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eAntohi\u003c/b\u003e \u003cb\u003eet al\u003c/b\u003e., \u003cb\u003e2021\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible and craniofacial bones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eImpacted teeth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eMultiple colonic polyps (approximately 50\u0026ndash;70)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMandible, temporal and frontal bone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSupernumerary and impacted teeth and hypercementosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eChest lipoma\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eColonic polyps\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSaito\u003c/b\u003e \u003cb\u003eet al\u003c/b\u003e., \u003cb\u003e2021\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e29 years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCranial and facial bones\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eOdontoma, retained and impacted teeth, osteosclerosis of maxilla and mandible\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eN/R\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eMultiple polyps in stomach and colon\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"9\"\u003e\u003cem\u003eM: male; F: female; N/R: not reported; Approx: approximately.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eIn addition, a targeted search was conducted to identify previous reports of Chilean patients with familial adenomatous polyposis presenting with orofacial manifestations. One article was found, published by Urz\u0026uacute;a-Orellana et al. in 2018, which describes a Chilean family with a clinical diagnosis of familial adenomatous polyposis, in which odontoma, osteomas, and various dental malformations were observed during the dental clinical examination. However, this report does not include a genetic study [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOn the other hand, a search was conducted to identify previous reports of Chilean patients with familial adenomatous polyposis presenting with orofacial manifestations. An article published by Urz\u0026uacute;a-Orellana et al. in 2018 was found, describing a Chilean family with a clinical diagnosis of familial adenomatous polyposis, in which odontoma, osteomas, and various dental malformations were observed during the dental clinical examination. However, this report does not include genetic testing [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIt should be noted that this case represents the first to be referred by a dentist at Cl\u0026iacute;nica de los Andes, Santiago, Chile. Despite the low incidence of Gardner syndrome, its clinical and radiographic features are well defined. In this context, panoramic radiography and a routine examination in dental practice, is key in patients with Gardner syndrome.\u003c/p\u003e\u003cp\u003eIn particular, regarding the management of mandibular osteomas, it is usually conservative when they are asymptomatic. However, in cases like ours, where facial aesthetics are compromised and this could have psychological repercussions for the patient, surgical intervention is considered the most appropriate alternative. Therefore, it is recommended to individualize the treatment, taking into account factors such as the size and location of the bone lesion [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIt is essential for the dentist to recognize the clinical signs of systemic diseases with craniofacial manifestations, as they may be the first indication of a diagnostic suspicion and thus allow for timely referral. Adequate knowledge of these diseases not only has a positive impact on the patient\u0026rsquo;s clinical outcome but also benefits their family members by identifying possible hereditary cases, as was the case with our patient\u0026rsquo;s family. Since GS is an autosomal dominant disease, the evaluation of direct relatives through genetic testing and early colonoscopies is highly relevant to identify asymptomatic carriers and significantly reduce the mortality associated with this syndrome. In case of any diagnostic uncertainty, it is essential to turn to a multidisciplinary team that can address the needs of the patient and their family in a comprehensive and effective manner.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eCraniofacial manifestations of GS are varied, developing mainly during puberty and generally preceding the appearance of gastrointestinal polyps. These manifestations are primarily associated with the presence of osteomas and dental anomalies.\u003c/p\u003e\u003cp\u003eIn this case, the initial dental diagnosis not only confirmed the disease in the patient but also led to the identification of the mutation in family members through genetic testing, which resulted in timely treatment. These findings reinforce the importance of a multidisciplinary approach and family evaluation in GS, highlighting the role of the dentist in early detection and referral.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u0026nbsp;GS: Gardner Syndrome.\u003cbr\u003e\u0026nbsp; FAP: Familial Adenomatous Polyposis.\u003cbr\u003e\u0026nbsp; APC: Adenomatous Polyposis Coli gene.\u003cbr\u003e\u0026nbsp; CBCT: Cone Beam Computed Tomography.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u003cbr\u003e\u003c/strong\u003eThis case report was approved by the Scientific Ethics Committee of Universidad de los Andes. Reference number: CEC2023093.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA signed informed consent form for publication was obtained directly from the patient. Although the patient was 17 years old when clinical treatment initially began, consent for publication was obtained later, when the patient was 21 years old and had already reached the age of majority in Chile. At that time, he was fully capable of understanding the nature and purpose of this case report; therefore, consent from a legal guardian was not required. In addition, at the beginning of treatment, when the patient was still a minor, informed consent for all clinical procedures was provided by the patient's mother, and assent was obtained from the patient himself.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article. The datasets used and/or analysed are available from the corresponding author on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere was no funding for this case report.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor’s Contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConcept and design: CV, CN, PR. Administrative support: MS, CN, PR. Provision of study materials or patients: CV, KA, FR, FL. Data collection and assembly: CV, KA, CN, PR, IC, FL, DO. Data analysis and interpretation: CV, CN, PR, MP, KA, JJ, FL. Manuscript writing and final approval: CV, KA, CN, PR, MP, JJ, FL, DO.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank the patient of this study for his contribution to scientific knowledge and the clinic of Universidad de Los Andes for the authorization and commitment.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eUse of AI:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring this preparation of the work, the authors use ChatGPT 4.0 only for the translation and edition of the document. The authors reviewed and edited the content as needed and take full responsibility for the content of the publication.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCharifa A, Jamil RT, Sathe NC, Zhang X. Gardner Syndrome. En: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.ncbi.nlm.nih.gov/books/NBK482342/\u003c/span\u003e\u003cspan address=\"http://www.ncbi.nlm.nih.gov/books/NBK482342/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGorling R, Cohen M, Hennekam R. Gorlin - Syndromes of the Head and Neck. Oxford university press; 2001. 1344 p. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.academia.edu/37214951/Gorlin_Syndromes_of_the_Head_and_Neck\u003c/span\u003e\u003cspan address=\"https://www.academia.edu/37214951/Gorlin_Syndromes_of_the_Head_and_Neck\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWeiss JM, Gupta S, Burke CA, Axell L, Chen LM, Chung DC et al. NCCN Guidelines\u0026reg; Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 1.2021. J Natl Compr Cancer Netw JNCCN. 15 de octubre de 2021;19(10):1122\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNeville B, Damm D, Allen C, Chi A. Oral and Maxillofacial Pathology, 4th Edition. St. Louis, Missouri: Saunders;. 928 p. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://evolve.elsevier.com/cs/product/9781455770526?role=student\u003c/span\u003e\u003cspan address=\"https://evolve.elsevier.com/cs/product/9781455770526?role=student\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJuhn E, Khachemoune A. Gardner syndrome: skin manifestations, differential diagnosis and management. Am J Clin Dermatol. 2010;11(2):117\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFearnhead NS, Britton MP, Bodmer WF. The ABC of APC. Hum Mol Genet 1 de abril de. 2001;10(7):721\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGaliatsatos P, Foulkes WD. Familial Adenomatous Polyposis. 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Hum Mol Genet marzo. 1995;4(3):337\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBisgaard ML, B\u0026uuml;low S. Familial adenomatous polyposis (FAP): genotype correlation to FAP phenotype with osteomas and sebaceous cysts. Am J Med Genet 1 de febrero de. 2006;140(3):200\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBertario L, Russo A, Sala P, Varesco L, Giarola M, Mondini P et al. Multiple approach to the exploration of genotype-phenotype correlations in familial adenomatous polyposis. J Clin Oncol Off J Am Soc Clin Oncol. 1 de mayo de. 2003;21(9):1698\u0026thinsp;\u0026ndash;\u0026thinsp;707.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIda M, Nakamura T, Utsunomiya J. Osteomatous changes and tooth abnormalities found in the jaw of patients with adenomatosis coli. 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Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.1007/s12663-023-01871-1\u003c/span\u003e\u003cspan address=\"10.1007/s12663-023-01871-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKozan R, Taşd\u0026ouml;ven İ, Seven TE, Aydemir S, Doğan G\u0026uuml;n B, C\u0026ouml;mert M. Gardner\u0026rsquo;s syndrome: Simultaneous diagnosis and treatment in monozygotic twins. Turk J Surg [Internet]. 2022;38(4):413\u0026ndash;7. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.47717/turkjsurg.2022.4218\u003c/span\u003e\u003cspan address=\"10.47717/turkjsurg.2022.4218\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBahena-Mart\u0026iacute;nez E, Tiol-Morales A, Tiol-Carrillo A. S\u0026iacute;ndrome de Gardner: informe de un caso y revisi\u0026oacute;n de la literatura. Rev ADM [Internet]. 2021;78(6):356\u0026ndash;60. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.medigraphic.com/pdfs/adm/od-2021/od216h.pdf\u003c/span\u003e\u003cspan address=\"https://www.medigraphic.com/pdfs/adm/od-2021/od216h.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAntohi C, Haba D, Caba L, Ciofu ML, Drug V-L, Bărboi O-B et al. Novel mutation in APC gene associated with multiple osteomas in a family and review of genotype-phenotype correlations of extracolonic manifestations in Gardner syndrome. Diagnostics (Basel) [Internet]. 2021;11(9):1560. 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Manifestaciones maxilofaciales en una familia chilena con adenomatosis poliposa familiar. Rev cl\u0026iacute;n periodoncia implantol rehabil oral. 2018;11(3):157\u0026ndash;9. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.scielo.cl/pdf/piro/v11n3/0719-0107-piro-11-03-157.pdf\u003c/span\u003e\u003cspan address=\"https://www.scielo.cl/pdf/piro/v11n3/0719-0107-piro-11-03-157.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBoffano P, Roccia F, Campisi P, Gallesio C. Review of 43 osteomas of the craniomaxillofacial region. J Oral Maxillofac Surg Off J Am Assoc Oral Maxillofac Surg mayo de. 2012;70(5):1093\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Gardner syndrome, colonic polyps, multidisciplinary approach, genetic testing, case report","lastPublishedDoi":"10.21203/rs.3.rs-7096806/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7096806/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eGardner syndrome is a phenotypic variant of familial adenomatous polyposis (FAP) with autosomal dominant inheritance, characterized by the diagnostic triad of multiple gastrointestinal polyps, skin and soft tissue tumors, and osteomas, which typically present in the mandible, skull, and long bones. Early detection of these signs is crucial due to the high risk of malignant transformation of colonic polyps before the age of 50.\u003c/p\u003e\u003ch2\u003eCase presentation:\u003c/h2\u003e\u003cp\u003eA 17-year-old male patient presented to a dental clinic seeking dental alignment. Clinical examination revealed facial asymmetry, and panoramic radiography showed multiple osteomas, supernumerary teeth, retained deciduous teeth, and impacted permanent teeth. Additionally, the patient had a history of hepatoblastoma at 18 months of age. Given the clinical suspicion of Gardner syndrome, an endoscopic evaluation was performed, revealing more than 40 polyps in the right colon and over 100 sessile polyps in the fundus and body of the stomach. Histopathological analysis reported colonic adenomas with low- and high-grade dysplasia, along with fundic gland polyps. A genetic panel confirmed a heterozygous pathogenic variant in exon 5 of the APC gene: c.509_512del (p.Asp170Valfs*4). Subsequently, first-degree relatives underwent genetic testing, which revealed that the patient\u0026rsquo;s mother and 21-year-old brother were asymptomatic carriers of the same pathogenic variant, with no extracolonic manifestations.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eThis case illustrates how a diagnostic suspicion originating in dental practice, combined with a multidisciplinary approach, can play a decisive role in both the diagnosis and prevention of complications associated with Gardner syndrome. It also underscores the importance of genetic testing in autosomal dominant disorders to identify asymptomatic carriers, enable early diagnosis, and implement timely prophylactic measures in at-risk relatives.\u003c/p\u003e","manuscriptTitle":"Challenges in diagnosing and interdisciplinary treatment of a patient with Gardner syndrome: a case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-18 14:11:46","doi":"10.21203/rs.3.rs-7096806/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-03-04T10:11:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"335756475277151273327705049123163888184","date":"2026-02-25T16:48:47+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-22T08:53:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"148424709096145181360426591109064207841","date":"2026-02-20T11:55:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"197349052611099556965476851471019955965","date":"2026-02-20T11:28:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"230292789660925876472671512254658931082","date":"2026-02-13T17:23:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"204812785912891187781323009396114771846","date":"2025-09-26T18:12:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-26T09:19:11+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-09T06:38:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-22T08:57:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-22T01:52:19+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-07-22T01:49:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7bcdaf38-37da-4c0e-adf0-897c90583dfb","owner":[],"postedDate":"October 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-10-18T14:11:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-18 14:11:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7096806","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7096806","identity":"rs-7096806","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}