Apocrine carcinoma is a rare tumor that most commonly arises in the axilla but can be seen in other locations. There are a variety of growth patterns including glandular, tubular, papillary or in this instance, irregular nests. The tumor, in contrast to apocrine adenoma, is poorly circumscribed with an infiltrating border as demonstrated in this image. Hyperchromatic and pleomorphic nuclei are identifiable in the tumor cells even at medium magnification. Desmoplastic inflamed stroma is seen in response to the invasive tumor.