Fig. 3.

Serous cystadenoma. (A) Well-defined, polycystic mass involving the head of the pancreas. This gross appearance is seen as sponge-like or “honeycomb” on imaging. Note the central stellate scar and the delicate septa which can also be identified on imaging. (B) Low magnification shows a well circumscribed mass, adjacent to uninvolved pancreas (top left), with multiple, back to back, small thin-walled cysts filled with clear serous fluid. Interestingly, the cysts do not communicate with the pancreatic duct as seen in mucinous cystic neoplasms. (C) Rich capillary network contributes to the enhancement on CT imaging. (D) The epithelium lining the cystic spaces is composed of uniform columnar cells with pale cytoplasm rich in glycogen, without atypia or mitotic activity. This bland cytomorphology of a benign neoplasm can be deceiving in cases of serous cystadenocarcinoma, an extremely rare but morphologically indistinguishable tumor from serous cystadenoma.