Mammary pilar metaplasia.

This article discusses a rare histologic phenomenon called mammary pilar metaplasia, which involves the differentiation of mammary epithelia into hair matric. The case presented in the article is of a 43-year-old woman with bilateral milky nipple discharge and hyperprolactinemia. The patient underwent various tests and procedures, including an MRI scan and lumpectomy, which revealed atypical ductal hyperplasia and the presence of dilated ducts with mature hair shafts. Mammary pilar metaplasia is typically observed in gender-affirming mastectomies and in a specific genetic syndrome, but the etiology in this case remains unclear. [Extracted from the article]