Pancreatic cystic endocrine neoplasms.

A rare case of cystic pancreatic endocrine tumor is presented, and the literature is reviewed. The patient was initially misdiagnosed as having a pancreatic pseudocyst, and that condition was managed accordingly. Persistence of the cystic lesion and reoperation led to the correct diagnosis and management. The neoplasm stained positive for glucagon and pancreatic polypeptide, but there were no clinical abnormalities that suggested hyperfunction. All cystic lesions of the pancreas should undergo biopsy at operation, to avoid an erroneous diagnosis of benign pseudocyst. Neoplastic lesions should be resected, not internally drained.