The Histologic Spectrum of Apocrine Lesions of the Breast

Apocrine proliferations most often are metaplasia as a component offibrocystic change. However, the appearance of apocrine metaplasia within various breast lesions, such as papillomas, ductal adenomas, and sclerosing adenosis, may complicate their diagnosis. Distinguishing benign from malignant apocrine proliferations can be problematic owing to the nuclear characteristics of apocrine cells. In this article, we characterize the spectrum of apocrine proliferations in the breast ranging from benign to malignant and attempt to clarify the difficult lesions that are intermediate between hyperplasia and ductal carcinoma in situ.