Abstract
Peritoneal malignant mesothelioma is an uncommon neoplasm with a poor prognosis. We hereby report a case of a 20-year-old male, first diagnosed on biopsy with axillary lymph node metastasis. He presented with abdominal pain and axillary lymphadenopathy, with no history of asbestos exposure. CECT showed peritoneal thickening and ascites. Ascitic fluid cytology showed reactive morphology. The diagnosis of metastatic deposits of malignant mesothelioma was made on histopathology and confirmed by immunohistochemistry. Tumor cells were immune-reactive for CK 5/6, calretinin, D2-40, and WT1 and negative for TTF1, CK 20, and CD 3. This case report has two important highlights-(i) unusual presentation with axillary lymph node metastasis leading to diagnostic dilemma in a young male with no asbestos exposure history and (ii) confirmatory diagnostic role of IHC in Peritoneal malignant mesothelioma.