Apocrine metaplasia in cystic hyperplastic mastopathy. Histochemical and ultrastructural observations.

A histochemical and ultrastructural investigation of apocrine cells in the human breast has been carried out. These cells showed strong oxidative enzymatic activity, large numbers of mitochondria and numerous infoldings of the basal plasma membrane. In these features, such cells resemble the normal apocrine gland cells. These observations support the view that this lesion is a metaplastic change in normal breast epithelium.