Endoscopic ultrasound-guided fine-needle aspiration of melanoma metastatic to the pancreas: report of two cases and review.

Malignant melanoma is a neoplasm which originates from melanocytes. Surgical exploration for abdominal metastases of cutaneous melanoma reveals pancreatic metastases in 16 % of patients which is usually accompanied by other intra-abdominal spread. Endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) of primary and metastatic pancreatic masses have already been described. We report the first use of EUS-FNA for the diagnosis of malignant melanoma metastatic to the pancreas. As our cases illustrate, these lesions may present as either cystic or solid pancreatic masses. Preparation of a cell block from the FNA aspirate and use of immunostaining may help to obtain the diagnosis. Despite thorough examination of the skin and mucous membranes, however, a primary site might not be found in these patients.