A case of malignant asymptomatic pancreatic endocrinoma with extrapancreatic growth

We describe a case of malignant asymptomatic pancreatic endocrinoma with extrapancreatic growth. A 75-year-old man was seen at a nearby hospital because of general fatigue. He was admitted to our department for close examination. Preoperatively, an extraluminal leiomyosarcoma of the remnant stomach was suspected. At laparotomy, malignant lymphoma invading the small part of the pancreatic tail was suspected, and the tumor was extirpated. The histopathological diagnosis was malignant pancreatic endocrinoma with extrapancreatic growth. With immunocytochemical staining, this tumor was positive for only pancreatic polypeptide (PP). This result suggested the possibility of pancreatic polypeptide-producing endocrinoma (PPoma). At 1 year and 8 months after the operation, abdominal CT showed swelling of the para-aortic lymph nodes. PPomas are very rare. Only 55 cases including this case have been reported in the Japanese and foreign literature. An asymptomatic pancreatic endocrinoma with extrapancreatic growth has not been reported in the Japanese literature. The preoperative diagnosis of asymptomatic tumors with extrapancreatic growth is considered to be very difficult.