Synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (Suricata suricatta): A case report

Synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (Suricata suricatta): A case report | 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 Case Report Synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (Suricata suricatta): A case report Jeong-Seop Oh, Na-Young Lee, Eun Jung, Ki-Yong Shin, Hyeon-Joo Shin, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7579763/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Dec, 2025 Read the published version in BMC Veterinary Research → Version 1 posted 11 You are reading this latest preprint version Abstract Background : Improvements in veterinary medicine have markedly prolonged the lifespan of zoo animals. With this longevity, conditions once seldom recognized, such as neoplastic diseases, are increasing. Nevertheless, multiple primary malignant tumors (MPMTs) remain rarely reported and pose substantial diagnostic challenges in veterinary practice. Here, we report the first documented case of synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat ( Suricata suricatta ), underscoring the importance of thorough diagnostic evaluation in zoo animal management. Case presentation: An 11-year-old captive female meerkat presented with progressive abdominal distension. Clinical examination and diagnostic imaging revealed significant uterine enlargement and multiple pulmonary nodules. Exploratory laparotomy and ovariohysterectomy were performed, and a 5-cm uterine mass was removed. Grossly, the mass showed extensive multifocal necrosis, and leiomyosarcoma was diagnosed through histopathologic examination. Following the diagnosis of uterine leiomyosarcoma, the pulmonary nodules were presumed to be metastatic. Given their multilobar involvement and the patient’s advanced age, invasive diagnostic procedures were not performed, and palliative care was provided. The meerkat survived for 15 months in stable condition. Postmortem examination revealed that the pulmonary nodules were primary adenocarcinomas, thereby confirming the synchronous occurrence of two distinct primary malignancies. Conclusions : This case emphasizes the importance of timely biopsy and thorough postmortem examination for distinguishing multiple primary malignancies from metastatic disease. With the increasing longevity of zoo animals, geriatric health management strategies including routine screenings and comprehensive diagnostics are essential for clinical decision-making and animal welfare. Multiple primary malignant tumors (MPMTs) Synchronous malignancies Uterine leiomyosarcoma Pulmonary adenocarcinoma Meerkat Suricata suricatta Figures Figure 1 Figure 2 Background Meerkats ( Suricata suricatta ) are small carnivores belonging to the mongoose family ( Herpestidae ), native to southwestern Africa. Although currently listed as Least Concern by the International Union for Conservation of Nature, their populations face various health challenges in both wild and captive environments [1]. Diseases reported in meerkats include infectious conditions such as toxoplasmosis and tuberculosis [2, 3]. A comprehensive literature review across PubMed, Web of Science, and Scopus reveals documented neoplastic diseases in meerkats, including hepatocellular carcinoma [4], intrahepatic cholangiocarcinoma [5], hepatic liposarcoma [6], intrathoracic liposarcoma [7] and anaplastic mandibular carcinoma [8]. However, neither uterine leiomyosarcoma nor primary pulmonary adenocarcinoma has been reported in this species. Multiple primary malignant tumors (MPMTs), defined as two or more histologically distinct malignancies arising independently within a single individual, present significant diagnostic and therapeutic challenges in clinical oncology [9, 10]. In human oncology, the prevalence of MPMTs ranges from 1.0–21.0% [9-11], with incidence rising with age [11, 12]. MPMTs are classified as synchronous or metachronous depending on the diagnostic interval; synchronous tumors, defined as those diagnosed within six months, are relatively rare, whereas metachronous tumors are more common [10-12]. Frequently reported combinations of synchronous malignancies include gastrointestinal (GI)-GI, GI–pulmonary pairs, and head and neck cancers co-occurring with GI tumors [12-14]. Although the exact pathogenesis of MPMTs remains unclear, their development appears to be influenced by multiple factors including patient age, lifestyle-related exposures (e.g., tobacco and alcohol), geographic distribution, and genetic susceptibility [9, 11, 14, 15]. In veterinary medicine, cases of MPMTs have been documented in some species, but their prevalence varies and diagnostic criteria are not standardized [16-19]. Cases in companion animals such as dogs and cats are limited compared with human studies, and reports in zoological or wildlife species are even rarer due to difficulties in long-term monitoring and antemortem diagnosis. Nevertheless, a few cases have been described, including concurrent thyroid adenocarcinoma and gastric adenocarcinoma in a captive jungle cat ( Felis chaus ) [20], and hepatosplenic hemangiosarcoma and intestinal lymphoma in an Asian small-clawed otter ( Aonyx cinereus ) [21]. To our knowledge, this is the first reported case of synchronous uterine leiomyosarcoma and primary pulmonary adenocarcinoma in a meerkat, underscoring the importance of ongoing pathology surveillance in aging captive animals. Case Presentation An 11-year-old geriatric female meerkat, weighing 760 g and with a history of childbirth, was regularly monitored through annual health assessments. During her most recent evaluation, complete blood count and serum chemistry analysis revealed no abnormalities; however, physical examination identified progressive abdominal distension. Abdominal radiographs demonstrated marked uterine enlargement, and concurrent thoracic radiographs revealed multiple pulmonary nodules bilaterally ( Fig. 1 , A and B ). Exploratory laparotomy was performed, confirming the presence of a uterine mass, which was subsequently removed by ovariohysterectomy. Anesthesia for the ovariohysterectomy was induced with isoflurane in oxygen in an induction chamber and maintained via face mask. Continuous monitoring included ECG, pulse oximetry, capnography, and temperature, with active warming throughout. Perioperative analgesia consisted of meloxicam (0.1 mg/kg SC). Gross examination of the excised uterine mass (approximately 5 cm in diameter) showed a firm, white-to-tan neoplasm completely occupying the uterine lumen, with multifocal areas of necrosis and hemorrhage observed upon cross-sectional inspection (Fig. 1C ). Samples were fixed in 10% neutral buffered formalin and routinely processed for histopathologic evaluation. Tissue sections were stained with hematoxylin and eosin (H&E), and immunohistochemistry (IHC) was performed for desmin and smooth muscle actin (SMA). For IHC, heat-induced antigen retrieval with citrate buffer (pH 6.0) and endogenous peroxidase blocking with 0.3% hydrogen peroxide were conducted. Primary antibodies against desmin (D33, dilution 1:200, mouse monoclonal, No. MU 071-UC, BioGenex Laboratory) and SMA (1A4, dilution 1:100, mouse monoclonal, No. M0851, Dako) were applied for 18 h at 4°C in a humidified chamber. Secondary anti-mouse horseradish peroxidase-conjugated antibodies were incubated with each primary antibody for 2 h at room temperature. Immunoreactivity was visualized using 3,3'-diaminobenzidine and counterstained with hematoxylin. Internal tissue components served as positive controls, while the primary antibody was omitted for negative controls. Histopathologic examination revealed a uterine mass composed of densely cellular, intersecting fascicles of spindle-shaped cells, accompanied by multifocal necrosis and hemorrhage ( Fig. 1D ). Neoplastic cells had abundant eosinophilic cytoplasm, vesicular oval nuclei, and approximately 3–4 mitotic figures per 2.37 mm 2 ( Fig. 1E ). No intravascular invasion or tumor emboli were noted. IHC demonstrated diffuse cytoplasmic immunoreactivity for desmin ( Fig. 1F ) and SMA ( Fig. 1G ), supporting smooth muscle origin and confirming a diagnosis of uterine leiomyosarcoma. Following diagnosis of uterine leiomyosarcoma, the pulmonary nodules were presumed to be metastatic lesions ( Fig. 1, A and B ). Due to the patient's geriatric status and multifocal pulmonary involvement, invasive diagnostic procedures and additional surgeries were not pursued, and supportive palliative management was provided. The meerkat died naturally following 15 months of prospective quality-of-life monitoring, with no sustained evidence of pain or distress ( Fig. 2, A and B ). At postmortem examination, multiple well-demarcated, white nodules (2–10 mm in diameter) were observed bilaterally in multiple lung lobes ( Fig. 2C ). No gross or microscopic evidence of distant metastasis or additional primary tumors in other organs was found. Histologically, the pulmonary nodules exhibited locally invasive growth with a predominant papillary pattern ( Fig. 2D ). Neoplastic cells were arranged along delicate fibrovascular cores, forming papillary projections lined by a single layer of cuboidal-to-columnar epithelial cells. The neoplastic cells had eosinophilic cytoplasm and round hyperchromatic nuclei with one to two inconspicuous nucleoli, often obscured by hyperchromasia. Nuclear atypia was mild to moderate, and loss of apico-basal polarity was evident with apical nuclear displacement ( Fig. 2E ). Mitotic activity was low, with 1–2 figures per 2.37 mm². Hemorrhage, necrosis, vascular invasion, and intravascular tumor emboli were absent. Notably, small nests of neoplastic cells were present within alveolar spaces beyond the tumor margin, representing tumor spread through air spaces (STAS; Fig. 2F ). Collectively, these findings supported a final diagnosis of papillary subtype pulmonary adenocarcinoma. Discussion and Conclusions Multiple primary malignant tumors involving distinct organ systems present significant diagnostic challenges. Such difficulties are exemplified in the present case, multiple pulmonary nodules were initially presumed to represent metastasis from the uterine leiomyosarcoma. Although pulmonary metastasis is a major clinical consideration in animals with a history of malignancy, alternative possibilities such as primary pulmonary adenocarcinoma or even benign lesions should also be considered [22]. Since prognosis and treatment options diverge widely depending on the underlying diagnosis, timely and accurate diagnosis is indispensable for guiding clinical decision-making. This case highlights why suspected metastatic lesions require definitive diagnosis, demonstrating that clinical impression alone may not always reflect the underlying pathology. Postmortem examination in the present case revealed histologically similar pulmonary adenocarcinomas distributed across multiple lobes. This presentation poses diagnostic challenges in distinguishing intrapulmonary metastases from synchronous primary tumors, particularly when histopathologic features are uniform. This distinction carries significant clinical implications, as metastatic lesions generally necessitate systemic therapies, whereas multiple primary tumors might be amenable to surgical intervention [9]. In this case, the presence of tumor spread through air spaces favored interpretation of intrapulmonary metastasis rather than multiple synchronous primaries [23]. In human oncology, advanced molecular techniques such as next-generation sequencing have significantly improved diagnostic accuracy in similar cases [24]. The application of these molecular approaches holds promise for veterinary oncology, but further validation across veterinary species remains essential. From a clinical management perspective, particularly for geriatric zoo animals, this case underscores the importance of regular health monitoring and tailored supportive care. As the lifespan of captive wildlife continues to extend through improved husbandry and veterinary surveillance, the prevalence of age-related conditions, including neoplasia, is expected to rise [25]. Accordingly, regular health evaluations that facilitate early disease detection are crucial for optimizing clinical outcomes [9]. Although invasive procedures such as surgery or chemotherapy may be viable in selected cases, careful assessment of risks versus benefits is essential, particularly for aged animals with limited resilience or coexisting morbidities. In this instance, palliative management effectively preserved quality of life and prolonged survival, suggesting that conservative treatment represents a reasonable option when invasive procedures offer limited benefit. To our knowledge, this is the first documented case of synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat, highlighting the diagnostic challenges associated with MPMTs in zoological medicine. This report emphasizes the need to consider MPMTs in the differential diagnosis rather than presuming metastatic disease, particularly in geriatric animals without definitive histopathological confirmation. Comprehensive clinical assessment combined with thorough postmortem examination remains essential for establishing accurate diagnoses and for advancing our understanding of cancer biology in captive wildlife. Future health management strategies should emphasize regular monitoring and individualized care to optimize outcomes in aging zoological populations. Abbreviations GI: Gastrointestinal H&E: Hematoxylin and eosin IHC: Immunohistochemistry MPMTs: Multiple primary malignant tumors SMA: Smooth muscle actin Declarations Ethics approval and consent to participate : Not applicable Consent for publication : All authors revised and approved the manuscript. Availability of data and materials : The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Competing interests : The authors declare no competing interests. Funding : This study was supported by BK21 FOUR Future Veterinary Medicine Leading Education and Research Center; National Research Foundation of Korea (grant number 2020R1A2C1010215). Authors' contributions : Each author made substantial contributions to the conception and design of the study, data acquisition, analysis, and interpretation. All authors participated in drafting the manuscript and revising it substantively, as well as approving the final version for submission. JS. Oh (Data curation: Lead; Methodology: Lead; Writing – original draft, review, and editing: Lead); NY. Lee (Methodology: Supporting); E. Jung (Resources: supporting); KY. Shin (Resources: Supporting); HS. Shin (Resources: Supporting); JY. Yang (Resources: Supporting); DH, Chung (Resources: Supporting); DY. Kim (Conceptualization: Lead; Funding acquisition: Lead; Project administration: Lead; Resources: Lead; Supervision: Lead; Writing – review and editing: Lead); SH. Youn (Conceptualization: Lead; Data curation: Lead; Funding acquisition: Lead; Project administration: Lead; Supervision: Lead; Writing – original draft: Lead; Writing – review and editing: Lead). All authors reviewed the manuscript. Acknowledgements : The author(s) would like to thank all staff members of the Laboratory of Veterinary Pathology, Department of Veterinary Medicine, College of Veterinary Medicine, Seoul National University, and Samsung Everland Zoological Garden for their invaluable support and contributions to this study. Authors' information (optional) : Jeong-Seop Oh: https://orcid.org/0000-0001-6753-1496 Na-Young Lee: https://orcid.org/0000-0002-6274-5740 Eun Jung: https://orcid.org/0009-0003-5625-1298 Ki-Yong Shin: https://orcid.org/0009-0002-8996-0632 Hyeon-Joo Shin: https://orcid.org/0009-0009-1194-2718 Joon-Young Yang: https://orcid.org/0009-0003-6042-9570 Dong-Hee Chung: Dae-Yong Kim: https://orcid.org/0000-0002-3168-3938 Soong-Hee Youn: https://orcid.org/0000-0002-0476-2366 References Jordan NR, Do Linh San E: Suricata suricatta . The IUCN Red List of Threatened Species 2015:e.T41624A45209377. 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Cite Share Download PDF Status: Published Journal Publication published 22 Dec, 2025 Read the published version in BMC Veterinary Research → Version 1 posted Editorial decision: Revision requested 21 Nov, 2025 Reviews received at journal 16 Nov, 2025 Reviewers agreed at journal 16 Nov, 2025 Reviews received at journal 06 Oct, 2025 Reviewers agreed at journal 25 Sep, 2025 Reviewers agreed at journal 25 Sep, 2025 Reviewers invited by journal 23 Sep, 2025 Editor assigned by journal 17 Sep, 2025 Editor invited by journal 16 Sep, 2025 Submission checks completed at journal 15 Sep, 2025 First submitted to journal 15 Sep, 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. 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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-7579763","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":524782707,"identity":"434856cc-0091-4ffb-b813-971a3e4990bc","order_by":0,"name":"Jeong-Seop Oh","email":"","orcid":"","institution":"Seoul National University","correspondingAuthor":false,"prefix":"","firstName":"Jeong-Seop","middleName":"","lastName":"Oh","suffix":""},{"id":524782709,"identity":"aaaf9652-7ec9-42c1-80d6-9fada662809f","order_by":1,"name":"Na-Young Lee","email":"","orcid":"","institution":"Seoul National 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1","display":"","copyAsset":false,"role":"figure","size":2419435,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRadiographic, gross, and histological features of uterine leiomyosarcoma in a meerkat (\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eSuricata suricatta\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(\u003cstrong\u003eA\u003c/strong\u003e, \u003cstrong\u003eB\u003c/strong\u003e) Ventrodorsal (A) and right lateral (B) abdominal and thoracic radiographs demonstrate a markedly enlarged abdominal soft tissue mass (white asterisk) and multiple discrete pulmonary nodules (red arrowheads). (\u003cstrong\u003eC\u003c/strong\u003e) Gross image of the excised uterine mass shows a firm, tan-white lesion with multifocal necrosis and hemorrhage. (\u003cstrong\u003eD\u003c/strong\u003e, \u003cstrong\u003eE\u003c/strong\u003e) Representative photomicrographs of the uterine mass stained with hematoxylin and eosin (H\u0026amp;E). (D) The mass is highly cellular with multifocal necrosis and hemorrhage (black asterisk). (E) Interlacing fascicles of spindle-shaped neoplastic cells with abundant eosinophilic cytoplasm and vesicular nuclei. (\u003cstrong\u003eF\u003c/strong\u003e, \u003cstrong\u003eG\u003c/strong\u003e) Immunohistochemistry shows diffuse cytoplasmic immunoreactivity for desmin (F) and smooth muscle actin (SMA; G). Scale bars: A and B = 5 cm; C = 1 cm; D = 500 µm; E–G = 50 µm.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7579763/v1/d7102ffac24b694df61fb67d.jpg"},{"id":92874253,"identity":"3107a3a7-9491-4d98-8f31-dc6f4873543d","added_by":"auto","created_at":"2025-10-06 14:26:16","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2971492,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRadiographic, gross, and histological features of papillary pulmonary adenocarcinoma in a meerkat (\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eSuricata suricatta\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(\u003cstrong\u003eA\u003c/strong\u003e, \u003cstrong\u003eB\u003c/strong\u003e) Ventrodorsal (A) and right lateral (B) abdominal and thoracic radiographs obtained 12 months after ovariohysterectomy demonstrate multiple, persistent, well-defined pulmonary nodules (red arrowheads). \u003cstrong\u003e(C)\u003c/strong\u003e Gross images of the postmortem lung show multiple, well-demarcated, white nodules (red arrowheads and white asterisks) distributed throughout multiple lobes. (\u003cstrong\u003eD–F\u003c/strong\u003e) Representative photomicrographs of pulmonary nodules stained with hematoxylin and eosin (H\u0026amp;E). (D) The nodule consists of an un-encapsulated but well-demarcated proliferation of neoplastic epithelial cells. (E) Neoplastic cells form papillary structures supported by fine fibrovascular stalks, lined by single cuboidal-to-columnar epithelium. Cells exhibit loss of apico-basal polarity, nuclear hyperchromasia, and increased nuclear-to-cytoplasmic ratio. (F) Nests of neoplastic cells within alveolar spaces beyond the tumor edge, representing spread through air spaces. Scale bars: A and B = 5 cm, C = 1 cm; D = 1 cm; E = 200 µm; F = 50 µm.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7579763/v1/ab14258c6c78a703106d4955.jpg"},{"id":99172414,"identity":"1b86e4fe-6edc-4cec-871d-49d1924e8049","added_by":"auto","created_at":"2025-12-29 16:09:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6992486,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7579763/v1/0abd6ddd-f4d7-40db-9207-0ad44d3d3ea2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (Suricata suricatta): A case report","fulltext":[{"header":"Background","content":"\u003cp\u003eMeerkats (\u003cem\u003eSuricata suricatta\u003c/em\u003e) are small carnivores belonging to the mongoose family (\u003cem\u003eHerpestidae\u003c/em\u003e), native to southwestern Africa. Although currently listed as Least Concern by the International Union for Conservation of Nature, their populations face various health challenges in both wild and captive environments\u0026nbsp;[1].\u0026nbsp;Diseases reported in meerkats include infectious conditions such as toxoplasmosis and tuberculosis\u0026nbsp;[2, 3].\u0026nbsp;A comprehensive literature review across PubMed, Web of Science, and Scopus reveals documented neoplastic diseases in meerkats,\u0026nbsp;including hepatocellular carcinoma [4], intrahepatic cholangiocarcinoma [5], hepatic liposarcoma [6],\u0026nbsp;intrathoracic liposarcoma\u0026nbsp;[7]\u0026nbsp;and anaplastic mandibular carcinoma [8].\u0026nbsp;However, neither uterine leiomyosarcoma nor primary pulmonary adenocarcinoma has been reported in this species.\u003c/p\u003e\n\u003cp\u003eMultiple primary malignant tumors (MPMTs), defined as two or more histologically distinct malignancies arising independently within a single individual, present significant diagnostic and therapeutic challenges in clinical oncology [9, 10]. In human oncology, the prevalence of MPMTs ranges from 1.0\u0026ndash;21.0% [9-11], with incidence rising with age [11, 12]. MPMTs are classified as synchronous or metachronous depending on the diagnostic interval; synchronous tumors, defined as those diagnosed within six months, are relatively rare, whereas metachronous tumors are more common\u0026nbsp;[10-12]. Frequently reported combinations of synchronous malignancies include gastrointestinal (GI)-GI, GI\u0026ndash;pulmonary pairs, and head and neck cancers co-occurring with GI tumors [12-14]. Although the exact pathogenesis of MPMTs remains unclear, their development appears to be influenced by multiple factors including patient age, lifestyle-related exposures (e.g., tobacco and alcohol), geographic distribution, and genetic susceptibility [9, 11, 14, 15].\u003c/p\u003e\n\u003cp\u003eIn veterinary medicine, cases of MPMTs have been documented\u0026nbsp;in some\u0026nbsp;species,\u0026nbsp;but\u0026nbsp;their prevalence varies\u0026nbsp;and\u0026nbsp;diagnostic criteria are not standardized\u0026nbsp;[16-19]. Cases in companion animals such as dogs and cats are limited compared with human studies, and reports in zoological or wildlife species are even rarer due to difficulties in long-term monitoring and antemortem diagnosis.\u0026nbsp;Nevertheless,\u0026nbsp;a few cases have been described, including\u0026nbsp;concurrent thyroid adenocarcinoma and gastric adenocarcinoma in a captive jungle cat\u0026nbsp;(\u003cem\u003eFelis chaus\u003c/em\u003e) [20], and hepatosplenic hemangiosarcoma and intestinal lymphoma in an Asian small-clawed otter (\u003cem\u003eAonyx cinereus\u003c/em\u003e)\u0026nbsp;[21].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo our knowledge, this is the first reported case of synchronous uterine leiomyosarcoma and primary pulmonary adenocarcinoma in a meerkat, underscoring the importance of ongoing pathology surveillance in aging captive animals.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eAn 11-year-old geriatric female meerkat, weighing 760 g and with a history of childbirth, was regularly monitored through annual health assessments. During her most recent evaluation, complete blood count and serum chemistry analysis revealed no abnormalities; however, physical examination identified progressive abdominal distension. Abdominal radiographs demonstrated marked uterine enlargement, and concurrent thoracic radiographs revealed multiple pulmonary nodules bilaterally\u0026nbsp;(\u003cstrong\u003eFig. 1\u003c/strong\u003e\u003cstrong\u003e, A and B\u003c/strong\u003e). Exploratory laparotomy was performed, confirming the presence of a uterine mass, which was subsequently removed by ovariohysterectomy.\u0026nbsp;Anesthesia for the ovariohysterectomy was induced with isoflurane in oxygen in an induction chamber and maintained via face mask. Continuous monitoring included ECG, pulse oximetry, capnography, and temperature, with active warming throughout. Perioperative analgesia consisted of meloxicam (0.1 mg/kg SC).\u003c/p\u003e\n\u003cp\u003eGross examination of the excised uterine mass (approximately 5 cm in diameter) showed a firm, white-to-tan neoplasm completely occupying the uterine lumen, with multifocal areas of necrosis and hemorrhage observed upon cross-sectional inspection\u003cstrong\u003e\u0026nbsp;(Fig.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1C\u003c/strong\u003e). Samples were fixed in 10% neutral buffered formalin and routinely processed for histopathologic evaluation. Tissue sections were stained with hematoxylin and eosin (H\u0026amp;E), and immunohistochemistry (IHC) was performed for desmin and smooth muscle actin (SMA). For IHC, heat-induced antigen retrieval with citrate buffer (pH 6.0) and endogenous peroxidase blocking with 0.3% hydrogen peroxide were conducted. Primary antibodies against desmin (D33, dilution 1:200, mouse monoclonal, No. MU 071-UC, BioGenex Laboratory) and SMA (1A4, dilution 1:100, mouse monoclonal, No. M0851, Dako) were applied for 18 h at 4\u0026deg;C in a humidified chamber. Secondary anti-mouse horseradish peroxidase-conjugated antibodies were incubated with each primary antibody for 2 h at room temperature. Immunoreactivity was visualized using 3,3\u0026apos;-diaminobenzidine and counterstained with hematoxylin.\u0026nbsp;Internal tissue components served as positive controls, while the primary antibody was omitted for negative controls.\u003c/p\u003e\n\u003cp\u003eHistopathologic examination revealed a uterine mass composed of densely cellular, intersecting fascicles of spindle-shaped cells, accompanied by multifocal necrosis\u0026nbsp;and\u0026nbsp;hemorrhage (\u003cstrong\u003eFig.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1D\u003c/strong\u003e). Neoplastic cells\u0026nbsp;had\u0026nbsp;abundant eosinophilic cytoplasm, vesicular oval nuclei, and approximately 3\u0026ndash;4 mitotic\u0026nbsp;figures\u0026nbsp;per 2.37 mm\u003csup\u003e2\u003c/sup\u003e (\u003cstrong\u003eFig.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1E\u003c/strong\u003e).\u0026nbsp;No intravascular\u0026nbsp;invasion or tumor\u0026nbsp;emboli were noted. IHC demonstrated diffuse cytoplasmic immunoreactivity for desmin (\u003cstrong\u003eFig.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1F\u003c/strong\u003e) and SMA (\u003cstrong\u003eFig.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1G\u003c/strong\u003e),\u0026nbsp;supporting smooth muscle origin and\u0026nbsp;confirming a diagnosis of uterine leiomyosarcoma.\u003c/p\u003e\n\u003cp\u003eFollowing diagnosis of uterine leiomyosarcoma, the pulmonary nodules were presumed to be metastatic lesions (\u003cstrong\u003eFig. 1, A and B\u003c/strong\u003e). Due to the patient\u0026apos;s geriatric status and multifocal pulmonary involvement, invasive diagnostic procedures and additional surgeries were not pursued, and supportive palliative management was provided. The meerkat died naturally following 15 months of prospective quality-of-life monitoring, with no sustained evidence of pain or distress (\u003cstrong\u003eFig. 2, A and B\u003c/strong\u003e).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAt postmortem examination, multiple well-demarcated, white nodules (2\u0026ndash;10 mm in diameter) were observed bilaterally in multiple lung lobes (\u003cstrong\u003eFig. 2C\u003c/strong\u003e). No gross or microscopic evidence of distant metastasis or additional primary tumors in other organs was found. Histologically, the pulmonary nodules exhibited locally invasive growth with a predominant papillary pattern (\u003cstrong\u003eFig. 2D\u003c/strong\u003e). Neoplastic cells were arranged along delicate fibrovascular cores, forming papillary projections lined by a single layer of cuboidal-to-columnar epithelial cells. The neoplastic cells had eosinophilic cytoplasm and round hyperchromatic nuclei with one to two inconspicuous nucleoli, often obscured by hyperchromasia. Nuclear atypia was mild to moderate, and loss of apico-basal polarity was evident with apical nuclear displacement (\u003cstrong\u003eFig. 2E\u003c/strong\u003e). Mitotic activity was low, with 1\u0026ndash;2 figures per 2.37 mm\u0026sup2;. Hemorrhage, necrosis, vascular invasion, and intravascular tumor emboli were absent. Notably, small nests of neoplastic cells were present within alveolar spaces beyond the tumor margin, representing tumor spread through air spaces (STAS; \u003cstrong\u003eFig. 2F\u003c/strong\u003e). Collectively, these findings supported a final diagnosis of papillary subtype pulmonary adenocarcinoma.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion and Conclusions ","content":"\u003cp\u003eMultiple primary malignant tumors involving distinct organ systems present significant diagnostic challenges. Such difficulties are exemplified in the present case, multiple pulmonary nodules were initially presumed to represent metastasis from the uterine leiomyosarcoma. Although pulmonary metastasis is a major clinical consideration in animals with a history of malignancy, alternative possibilities such as primary pulmonary adenocarcinoma or even benign lesions should also be considered [22]. Since prognosis and treatment options diverge widely depending on the underlying diagnosis, timely and accurate diagnosis is indispensable for guiding clinical decision-making. This case highlights why suspected metastatic lesions require definitive diagnosis, demonstrating that clinical impression alone may not always reflect the underlying pathology.\u003c/p\u003e\n\u003cp\u003ePostmortem examination in the present case revealed histologically similar pulmonary adenocarcinomas distributed across multiple lobes. This presentation poses diagnostic challenges in distinguishing intrapulmonary metastases from synchronous primary tumors, particularly when histopathologic features are uniform. This distinction carries significant clinical implications, as metastatic lesions generally necessitate systemic therapies, whereas multiple primary tumors might be amenable to surgical intervention\u0026nbsp;[9]. In this case, the presence of tumor spread through air spaces favored interpretation of intrapulmonary metastasis rather than multiple synchronous primaries [23]. In human oncology, advanced molecular techniques such as next-generation sequencing have significantly improved diagnostic accuracy in similar cases [24]. The application of these molecular approaches holds promise for veterinary oncology, but further validation across veterinary species remains essential.\u003c/p\u003e\n\u003cp\u003eFrom a clinical management perspective, particularly for geriatric zoo animals, this case underscores the importance of regular health monitoring and tailored supportive care. As the lifespan of captive wildlife continues to extend through improved husbandry and veterinary surveillance, the prevalence of age-related conditions, including neoplasia, is expected to rise [25]. Accordingly, regular health evaluations that facilitate early disease detection are crucial for optimizing clinical outcomes\u0026nbsp;[9]. Although invasive procedures such as surgery or chemotherapy may be viable in selected cases, careful assessment of risks versus benefits is essential, particularly for aged animals with limited resilience or coexisting morbidities. In this instance, palliative management effectively preserved quality of life and prolonged survival, suggesting that conservative treatment represents a reasonable option when invasive procedures offer limited benefit.\u003c/p\u003e\n\u003cp\u003eTo our knowledge, this is the first documented case of synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat, highlighting the diagnostic challenges associated with MPMTs in zoological medicine. This report emphasizes the need to consider MPMTs in the differential diagnosis rather than presuming metastatic disease, particularly in geriatric animals without definitive histopathological confirmation. Comprehensive clinical assessment combined with thorough postmortem examination remains essential for establishing accurate diagnoses and for advancing our understanding of cancer biology in captive wildlife. Future health management strategies should emphasize regular monitoring and individualized care to optimize outcomes in aging zoological populations.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eGI: Gastrointestinal\u003c/p\u003e\n\u003cp\u003eH\u0026amp;E: Hematoxylin and eosin\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIHC: Immunohistochemistry\u003c/p\u003e\n\u003cp\u003eMPMTs: Multiple primary malignant tumors\u003c/p\u003e\n\u003cp\u003eSMA: Smooth muscle actin\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e: Not applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e: All authors revised and approved the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e: The authors declare no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: This study was supported by BK21 FOUR Future Veterinary Medicine Leading Education and Research Center; National Research Foundation of Korea (grant number 2020R1A2C1010215).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e:\u0026nbsp;Each author made substantial contributions to the conception and design of the study, data acquisition, analysis, and interpretation. All authors participated in drafting the manuscript and revising it substantively, as well as approving the final version for submission.\u003c/p\u003e\n\u003cp\u003eJS. Oh (Data curation: Lead; Methodology: Lead; Writing \u0026ndash; original draft, review, and editing: Lead); NY. Lee (Methodology: Supporting); E. Jung (Resources: supporting); KY. Shin (Resources: Supporting); HS. Shin (Resources: Supporting); JY. Yang (Resources: Supporting); DH, Chung (Resources: Supporting); DY. Kim (Conceptualization: Lead; Funding acquisition: Lead; Project administration: Lead; Resources: Lead; Supervision: Lead; Writing \u0026ndash; review and editing: Lead); SH. Youn (Conceptualization: Lead; Data curation: Lead; Funding acquisition: Lead; Project administration: Lead; Supervision: Lead; Writing \u0026ndash; original draft: Lead; Writing \u0026ndash; review and editing: Lead). All authors reviewed the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e: The author(s) would like to thank all staff members of the Laboratory of Veterinary Pathology, Department of Veterinary Medicine, College of Veterinary Medicine, Seoul National University, and Samsung Everland Zoological Garden for their invaluable support and contributions to this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; information (optional)\u003c/strong\u003e:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eJeong-Seop Oh: https://orcid.org/0000-0001-6753-1496\u003c/p\u003e\n\u003cp\u003eNa-Young Lee: https://orcid.org/0000-0002-6274-5740\u003c/p\u003e\n\u003cp\u003eEun Jung: https://orcid.org/0009-0003-5625-1298\u003c/p\u003e\n\u003cp\u003eKi-Yong Shin: https://orcid.org/0009-0002-8996-0632\u003c/p\u003e\n\u003cp\u003eHyeon-Joo Shin: https://orcid.org/0009-0009-1194-2718\u003c/p\u003e\n\u003cp\u003eJoon-Young Yang: https://orcid.org/0009-0003-6042-9570\u003c/p\u003e\n\u003cp\u003eDong-Hee Chung:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDae-Yong Kim: https://orcid.org/0000-0002-3168-3938\u003c/p\u003e\n\u003cp\u003eSoong-Hee Youn: https://orcid.org/0000-0002-0476-2366\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJordan NR, Do Linh San E: \u003cstrong\u003e\u003cem\u003eSuricata suricatta\u003c/em\u003e\u003c/strong\u003e. \u003cem\u003eThe IUCN Red List of Threatened Species \u003c/em\u003e2015:e.T41624A45209377.\u003c/li\u003e\n\u003cli\u003eJuan-Sall\u0026eacute;s C, Prats N, L\u0026oacute;pez S, Domingo M, Marco AJ, Mor\u0026aacute;n JF: \u003cstrong\u003eEpizootic disseminated toxoplasmosis in captive slender-tailed meerkats (Suricata suricatta)\u003c/strong\u003e. \u003cem\u003eVet Pathol \u003c/em\u003e1997, \u003cstrong\u003e34\u003c/strong\u003e(1):1-7.\u003c/li\u003e\n\u003cli\u003eM\u0026uuml;ller-Klein N, Risely A, Schmid DW, Manser M, Clutton-Brock T, 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In: \u003cem\u003eThe Zoo and Wildlife Health Conference: June 7 2023; Valencia, Spain\u003c/em\u003e: European Association of Zoo and Wildlife Veterinarians; 2023.\u003c/li\u003e\n\u003cli\u003eCaparica R, Mak MP, Rocha CH, Velho PHI, Viana P, Moura MRL, Menezes MR, Amato MBP, Feher O: \u003cstrong\u003ePulmonary Nodules in Patients With Nonpulmonary Cancer: Not Always Metastases\u003c/strong\u003e. \u003cem\u003eJ Glob Oncol \u003c/em\u003e2016, \u003cstrong\u003e2\u003c/strong\u003e(3):138-144.\u003c/li\u003e\n\u003cli\u003eCooper WA, Bubendorf L, Kadota K, Ladanyi M, MacMahon H, Matsubara D, Russell PA, Scagliotti GV, Sholl LM, Van Schil PEY\u003cem\u003e et al\u003c/em\u003e: \u003cstrong\u003eInvasive non-mucinous adenocarcinoma of the lung\u003c/strong\u003e. In: \u003cem\u003eThoracic Tumours.\u003c/em\u003e 5 edn. Edited by Board WCoTE. Lyon, France: International Agency for Research on Cancer; 2021: 60-73.\u003c/li\u003e\n\u003cli\u003eLiu C, Liu C, Zou X, Shao L, Sun Y, Guo Y: \u003cstrong\u003eNext-generation sequencing facilitates differentiating between multiple primary lung cancer and intrapulmonary metastasis: a case series\u003c/strong\u003e. \u003cem\u003eDiagn Pathol \u003c/em\u003e2021, \u003cstrong\u003e16\u003c/strong\u003e(1):21.\u003c/li\u003e\n\u003cli\u003eKrebs BL, Marrin D, Phelps A, Krol L, Watters JV: \u003cstrong\u003eManaging Aged Animals in Zoos to Promote Positive Welfare: A Review and Future Directions\u003c/strong\u003e. \u003cem\u003eAnimals (Basel) \u003c/em\u003e2018, \u003cstrong\u003e8\u003c/strong\u003e(7).\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":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Multiple primary malignant tumors (MPMTs), Synchronous malignancies, Uterine leiomyosarcoma, Pulmonary adenocarcinoma, Meerkat, Suricata suricatta","lastPublishedDoi":"10.21203/rs.3.rs-7579763/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7579763/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Improvements in veterinary medicine have markedly prolonged the lifespan of zoo animals. With this longevity, conditions once seldom recognized, such as neoplastic diseases, are increasing. Nevertheless, multiple primary malignant tumors (MPMTs) remain rarely reported and pose substantial diagnostic challenges in veterinary practice. Here, we report the first documented case of synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (\u003cem\u003eSuricata suricatta\u003c/em\u003e), underscoring the importance of thorough diagnostic evaluation in zoo animal management.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation: \u003c/strong\u003eAn 11-year-old captive female meerkat presented with progressive abdominal distension. Clinical examination and diagnostic imaging revealed significant uterine enlargement and multiple pulmonary nodules. Exploratory laparotomy and ovariohysterectomy were performed, and a 5-cm uterine mass was removed. Grossly, the mass showed extensive multifocal necrosis, and leiomyosarcoma was diagnosed through histopathologic examination. Following the diagnosis of uterine leiomyosarcoma, the pulmonary nodules were presumed to be metastatic. Given their multilobar involvement and the patient’s advanced age, invasive diagnostic procedures were not performed, and palliative care was provided. The meerkat survived for 15 months in stable condition. Postmortem examination revealed that the pulmonary nodules were primary adenocarcinomas, thereby confirming the synchronous occurrence of two distinct primary malignancies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e: This case emphasizes the importance of timely biopsy and thorough postmortem examination for distinguishing multiple primary malignancies from metastatic disease. With the increasing longevity of zoo animals, geriatric health management strategies including routine screenings and comprehensive diagnostics are essential for clinical decision-making and animal welfare.\u003c/p\u003e","manuscriptTitle":"Synchronous uterine leiomyosarcoma and pulmonary adenocarcinoma in a meerkat (Suricata suricatta): A case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-06 14:18:11","doi":"10.21203/rs.3.rs-7579763/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-21T13:44:56+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-16T23:47:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"124834125932034042110631019262483458671","date":"2025-11-16T22:48:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-06T04:32:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"36435751824314479257842056587520266123","date":"2025-09-25T11:05:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"81316654909856956668165462148292961668","date":"2025-09-25T05:15:31+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-23T08:12:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-17T10:50:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-16T04:32:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-16T03:40:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Veterinary Research","date":"2025-09-16T03:37:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e79eb3e5-7474-4269-be7c-91bb8dedeba0","owner":[],"postedDate":"October 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-29T16:03:28+00:00","versionOfRecord":{"articleIdentity":"rs-7579763","link":"https://doi.org/10.1186/s12917-025-05242-5","journal":{"identity":"bmc-veterinary-research","isVorOnly":false,"title":"BMC Veterinary Research"},"publishedOn":"2025-12-22 15:58:32","publishedOnDateReadable":"December 22nd, 2025"},"versionCreatedAt":"2025-10-06 14:18:11","video":"","vorDoi":"10.1186/s12917-025-05242-5","vorDoiUrl":"https://doi.org/10.1186/s12917-025-05242-5","workflowStages":[]},"version":"v1","identity":"rs-7579763","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7579763","identity":"rs-7579763","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}