Cystic neoplasms of the pancreas. Radiological-pathological correlation.

Microcystic adenomas and mucinous cystic neoplasms of the pancreas have often been described interchangeably (cystadenoma, cystadenocarcinoma), causing confusion with respect to their radiographic characteristics. The former are composed of innumerable tiny cysts and are benign, whereas the latter contain large, unilocular or multilocular cysts, sometimes with shaggy excrescences, and are either frankly or potentially malignant. Microcystic adenomas are angiographically hypervascular and may have central calcification. Sonographically, they have a mixed hypoechoic and echogenic pattern, while CT numbers reflect a mixture of connective tissue and proteinaceous fluid and contrast enhancement is seen. Mucinous cystic neoplasms are hypovascular and may have peripheral calcification; ultrasound and CT reflect their predominantly cystic character and demonstrate excrescences when present.