Fine-needle aspiration of an apocrine breast carcinoma with multivacuolated, lipid-rich, giant cells.

The frequency of mammary apocrine carcinoma varies considerably and reflects the definitional differences of various researchers. Lipid synthesis by malignant mammary cells is not uncommon, and occasionally it is so extensive that the designation lipid-rich carcinoma is warranted. Many subtypes of lipid-rich carcinoma are described. Although focal apocrine change is observed in one type, a tumor composed predominantly of an apocrine carcinoma with an intimate admixture of lipid-rich malignant cells is previously undescribed. The fine-needle aspiration, histologic, and ultrastructural features of such a tumor is delineated for which the descriptive title lipid-rich apocrine carcinoma is coined.