Psammoma bodies in endocrine tumors of the gastroenteropancreatic axis: a rather common occurrence.

Seventeen of 204 cases of gastroenteropancreatic tumors contained psammoma bodies (8%). Of these 17, ten were B cell tumors, representing 33% of the B cell tumors studied. Three tumors of the appendix and four tumors of the small bowel also had psammoma bodies. Electron microscopic studies revealed that the bodies appeared to have two possible sites of origin: intracellular (type I) and intraluminal from secretory products of the tumor cells (type II). Awareness by surgical pathologists of the fact that variable degrees of calcification in endocrine tumors of the gastroenteropancreatic system is a rather common occurrence may be important, especially in frozen section diagnosis.