FINAL DIAGNOSIS: SEROUS OLIGOCYSTIC ADENOMA OF PANCREAS
Serous oligocystic adenoma (SOA) of the pancreas is defined by the World Health Organization as "a benign neoplasm composed of few, relatively large cysts, lined by uniform glycogen-rich cuboidal epithelial cells."1 It is closely related to the serous microcystic adenoma (SMA), with a few subtle differences. It most frequently occurs in the head or body of the pancreas, while SMA occurs most frequently in the body and tail. There is no sex predilection for SOA, while SMA tends to occur more frequently in females (70%).
The main criteria for distinguishing SOA from SMA are as follows:
Grossly, SOA is composed of a limited number of larger, easily defined cystic structures that are irregularly arranged and that lie within a fibrous stroma with no central focus. The cystic borders often extend into neighboring pancreatic parenchyma, giving these tumors an ill-defined edge. SMA, in contrast, consists of a well-circumscribed lesion, comprising numerous "sponge-like" cystic cavities that are arranged around a core of fibrous tissue known as a "central stellate scar."
Microscopically, these lesions share many features with some subtle exceptions. The epithelium of SOA tends to be more cuboidal, with larger nuclei. The cytoplasm of the epithelial cells in SOA is most often completely clear, due to the presence of abundant glycogen.
Serous oligocystic adenoma of pancreas has no known malignant potential.
Contributed by Kenneth Clark, MD and Teresa McHale, MD.