Pancreatic metastasis of Merkel cell carcinoma diagnosed by EUS-FNA: a case report and review literature.

Introduction Merkel cell carcinoma (MCC) is a rare primary skin tumor with aggressive behavior. We report a case of metastatic Merkel cell carcinoma of the pancreas diagnosed by endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) in an Asian male and review of the literature. Case presentation a 65-year-old Filipino man with history of primary cutaneous MCC of the left forearm presented with intractable nausea and vomiting. The patient was found to have a 3.5 x 4 cm pancreatic mass by abdominal computerized tomography. EUS-FNA was subsequently performed. The cytological and pathological examination revealed atypical cells with hyperchromatic nuclei. The immunohistochemical stains were consistent with MCC. To our knowledge, only seven such cases have been reported in the English literature. Discussion EUS-FNA of the pancreas can effectively obtain tissue adequate for establishing the diagnosis of metastatic MCC. Thorough knowledge of clinical history and accurate interpretation of cytology and cell block preparation obtained by EUS-FNA are essential to establish the definite diagnosis of MCC. Patients with metastatic MCC to the pancreas have a grave.