The diagnostic utility of Merkel cell polyomavirus immunohistochemistry in a fine needle aspirate of metastatic Merkel cell carcinoma of unknown primary to the pancreas. Issue 1 (12th August 2017)

• Record Type: Journal Article
• Authors: Li, Long; Molberg, Kyle; Cheedella, Naga; Thibodeaux, Joel; Hinson, Stacy; Lucas, Elena
• Is Part Of: Diagnostic cytopathology. Volume 46:Issue 1(2018)
• Page Start: 67
• Page End: 71
• Publication Date: 2017-08-12
• Subjects: immunohistochemistry -- Merkel cell carcinoma -- Merkel cell polyomavirus -- pancreas -- unknown primary; Cytodiagnosis -- Periodicals; Pathology, Cellular -- Periodicals; Cytology -- Periodicals; 616.07582
• DOI: 10.1002/dc.23794
• Languages: English
• ISSNs: 8755-1039

Abstract

Abstract: Merkel cell carcinoma (MCC) is an aggressive skin tumor with a high tendency for metastases. We report a case of MCC initially presenting as axillary and pancreatic metastases. A 33‐year‐old HIV‐positive Hispanic male presented with a history of a rapidly growing axillary mass. A needle core biopsy demonstrated an epithelioid neoplasm composed of small to medium‐sized cells with high nuclear‐cytoplasmic ratio, nuclear molding, and frequent mitotic figures. A subsequent PET scan revealed a 1.5 cm FDG avid mass in the pancreas. Endoscopic ultrasound‐guided FNA of the pancreatic mass showed neoplastic cells with similar morphology to those of the axillary mass. The tumor cells were positive with pancytokeratin AE1/AE3, CK20, CD56, synatophysin, chromogranin, and Merkel cell polyomavirus (MCPyV). This case of MCC most likely originated from a resolved primary skin lesion drained by the involved axillary lymph node with subsequent metastases to the pancreas and distant lymph nodes.