Apocrine Metaplasia in Intraductal Papilloma with Foci of DCIS: A Friend or Foe?

Malignant papillary neoplasms of the breast comprise a number of microscopically distinct lesions, where apocrine metaplasia is commonly found in papillomas compared to other papillary lesions including papillary carcinomas. However, association of apocrine metaplasia in papilloma with Ductal Carcinoma in Situ (DCIS) is not very well defined. The lesions with apocrine metaplasia are not only difficult to categories, but also there is controversy regarding their relative risk of subsequent carcinoma development. A case of extensive apocrine differentiation in duct papilloma with DCIS developing in the background of papillomatosis, posing a diagnostic dilemma for the pathologist and a therapeutic challenge for the surgeon, is hereby reported for its uniqueness and rarity. Awareness of this association should be kept in mind by both the pathologist as well as clinician for optimal therapeutic intervention.