Incidental detection of a microcystic adenoma of the pancreas.

Cystic neoplasms of the pancreas are uncommon. The two major types of cystic pancreatic neoplasms are microcystic (serous) cystadenoma and mucinous cystic lesions (mucinous cystadenoma and mucinous cystadenocarcinoma). The two types differ substantially in the long-term mortality. Symptoms and signs do not distinguish between the two types, and small lesions are often asymptomatic. The neoplasms may be discovered during imaging procedures for unrelated complaints. Computerized tomography may suggest the diagnosis of microcystic adenoma or mucinous cystic neoplasm when the features are typical, but the final diagnosis must be established by surgical biopsy. Characteristic gross findings, light microscopic findings, and immunohistochemical staining patterns distinguish between the two types. When preliminary open biopsy confirms microcystic adenoma, extensive unnecessary surgery can be avoided.