Pancreatic cystic neoplasms. Echographic-CT aspects and differential diagnosis

Cystic neoplasms of the pancreas are rare lesions. Following the Compagno-Oertel classification, we differentiated serous microcystic adenomas (SMA) from mucinous macrocystic adenomas/adenocarcinomas (MMA). The former are benign tumors with slow growth, composed by innumerable small and tiny cysts with central calcifications, resulting in a "honeycomb" pattern. They have a mixed US structure while CT densitometric values reflect a mixture of connective tissue and proteinaceous fluid. Postcontrast enhancement is frequently seen. MMA are potential (adenoma) or frankly (adenocarcinoma) malignant tumors. They appear as multilocular cystic masses containing septa and/or papillary bulges, with thickened walls. Both US and CT demonstrate their predominantly cystic character, and the eventual presence of excrescences. We report a series of 23 cases (6 SMA, 17 MMA) of cystic neoplasms of the pancreas studied during the past five years. A correct diagnosis of SMA was possible in all 6 cases, while MMA was correctly diagnosed in 17 out of 18 cases. There were no false negatives, and 1 false positive. All differential diagnoses are also discussed.