Microcystic adenoma of the pancreas with myoepithelial cells. A hitherto undescribed morphologic feature.

A case of microcystic adenoma (glycogen-rich cystadenoma) of the exocrine pancreas in a 62-year-old white female presenting with adult-onset diabetes mellitus is reported. Clinical, histopathologic, and ultrastructural findings are discussed with particular emphasis on the presence of myoepithelial cells, a morphologic feature not seen in this tumor previously. The controversy over diabetes mellitus as a significant related factor is also discussed.