Akademik Veri Yönetim Sistemi
37th European Congress of Pathology , Vienna, Avusturya, 6 - 10 Eylül 2025, ss.306, (Özet Bildiri)
Background & Objectives: Primary mucosal melanoma of the gas trointestinal (GI) tract is rare, constituting <1% of GI malignancies and 25-50% of melanomas in dark-skinned populations. Despite multimodal therapies, survival remains poor due to delayed diagno sis. This case highlights clinicopathological features to underscore diagnostic challenges and aggressive behaviour. Methods: A 63-year-old male presented with abdominal pain. Imaging revealed a 6x6.5 cm contrast-enhancing ileal mass. Sur gical resection (segmental small bowel resection, right hemicolec tomy, cholecystectomy) was performed. Specimens underwent macroscopic evaluation, histopathological analysis including immunohistochemistry. Results: Gross examination revealed an 8.6x6.2 cm polypoid tumour penetrating to serosa, multifocal brown lesions in the small intestine and distal colon. The gallbladder exhibited a 1.8 cm pigmented fundal lesion with adjacent ‘cat’s tongue’ mucosal changes, while the cystic duct contained a 0.3 cm brown intraluminal lesion contiguous with a 1 cm serosal pigmented focus. Microscopy revealed pleomorphic epithelioid/spindle melanocytic cells with vesicular nuclei, prominent nucleoli, and heavy pigmentation. Immunohistochemistry confirmed melanocytic differentiation (MelanA+, S100+, HMB45+). Tumour foci involved mucosa, submucosa, and subserosa of the small intes tine, colon, and gallbladder, with lymphovascular invasion and nodal metastasis. The largest lesion (8.6 cm polypoid mass) originated in the small intestine. Since no other primary focus was found in the patient’s dermatological examination and whole body scan, the largest polypoid mass in the small intestine was accepted as the primary lesion. Conclusion: This case exemplifies the aggressive nature of GI mucosal melanomas, often diagnosed at advanced stages due to nonspecific symptoms and occult anatomical sites. Histopathological and immu nohistochemical confirmation is critical, as seen in this multifocal, metastatic presentation. Early detection remains challenging, contrib uting to poor prognosis. Increased clinical suspicion and recognition of morphological diversity, including pigmented lesions and spindle-cell morphology, may facilitate timely intervention. Further research into molecular drivers (e.g., NRAS mutations) and targeted therapies is essential to improve outcomes in this lethal malignancy.