Malignant serous cystic neoplasm of the pancreas: report of a case and review of the literature.

BACKGROUND: In general, serous cystic neoplasms of the pancreas are thought to be benign. Malignant serous cystic neoplasm of the pancreas is a rare clinical entity. CASE REPORT: We report the case of an 87-year-old woman with a serous microcystic neoplasm in the tail of the pancreas that behaved in a malignant fashion. The neoplasm had also invaded the colonic mesentery and splenic hilum. The pancreatic lesion was diagnosed as a large malignant serous cystic neoplasm, and the patient underwent distal pancreatectomy with splenectomy and segmental colectomy. The resected specimen contained a large tumor, 12 x 9 x 8 cm, which occupied the body and tail of the pancreas. Histologically, the tumor was indistinguishable from serous cystadenoma. However, the tumor had invaded surrounding tissues including the splenic vein, and there were splenic invasion and a regional lymph node metastasis. The postoperative course was uneventful. DISCUSSION: There are few reported cases of malignant serous cystic neoplasm, in which malignancy was histologically confirmed in the resected specimen. There are no reports of a negative outcome with complete resection of the tumor. Surgical treatment should be considered for serous cystic neoplasms, especially large ones, because of the malignant potential.