Primary pancreatic low-grade mucosa-associated lymphoid tissue lymphoma presenting with multiple masses.

The case concerns a 55-year-old Japanese man with multiple pancreatic tumors that were incidentally detected by ultrasonography (US) in a routine medical examination. He consulted a doctor since either neuroendocrine tumors or metastases of small-cell lung carcinoma were suspected, because he had an abnormal shadow in the lung. Then he was transferred to our hospital. Imaging studies showed multiple pancreatic tumors of 3.0-cm diameter in the head, 1.0 cm in the body and 1.5 cm in the tail, respectively. Specimen by endoscopic ultrasonography fine-needle aspiration cytology (EUS-FNAC) revealed numerous B-cell lymphocytes, but a definite diagnosis of malignant lymphoma could not be obtained. Therefore, a segmental pancreatic body resection was performed to clarify the features of the tumor for appropriate therapy. Consequently, the final diagnosis was obtained as a low-grade B-cell lymphoma having a lymphoepithelial lesion, which indicated mucosa-associated lymphoid tissue (MALT) lymphoma. Radiation therapy with 31 Gy successfully resulted in complete remission. We report here for the first time on primary pancreatic low-grade MALT lymphoma presenting with multiple pancreatic masses.