Apocrine Encapsulated Papillary Carcinoma of the Breast: The First Reported Case with an Infiltrative Component

Apocrine encapsulated papillary carcinoma (EPC) of the breast is a rare neoplasm, and only 10 cases have been reported in the literature to date. Although EPC by definition lacks a peripheral myoepithelial layer, all previously published apocrine EPC cases were clinically indolent and lacked a conventional invasive component. Herein, we report the 11th case of apocrine EPC, which had a conventional invasive carcinoma component and provides evidence of the malignant potential of this entity. We postulate that apocrine EPC is most likely a morphological variant of conventional EPC, with the same unpredictable malignant potential as non-apocrine cases.