Acinar cell cystadenoma of the pancreas - Report of a case with metaplastic ossification

Acinar cell cystadenoma. (ACA) is a very rare cystic lesion of the pancreas. The lining epithelium of ACA is morphologically identical to acinar cells of the pancreas. It is uncertain whether ACA is a benign neoplasm or cystic transformation of acinar glands but it is worthy to consider ACA in the differential diagnosis of other cystic neoplasms of the pancreas. We report here a 25-year old-woman who was operated on for a cystic mass of the pancreas. Grossly, a multilocular cystic mass containing clear serous fluid was observed. There was no communication between the cysts and the pancreatic ducts. Microscopically, cysts of various size were lined by columnar, cuboidal or flattened epithelial cells with a few foci of pseudostratification. The cells had granular apical cytoplasm and basally located nuclei with minimal atypia, the same as normal acinar cells. Metaplastic ossification was noted in the stroma. Immunohistochemically, the lining epithelium was positive for cytokeratin 7, antitrypsin and antichymotrypsin.