Cytomorphology of rare malignant tumors of the breast.

This article reviews cytomorphology of rare malignant tumors of the breast: squamous carcinoma, metaplastic carcinoma, adenoid cystic carcinoma, apocrine carcinoma, secretory carcinoma, lipid-rich carcinoma, and carcinoma with choriocarcinomatous features. It is important to bear in mind the cytomorphology and diagnosis of rare malignant tumors of the breast in analysis of breast fine needle aspiration smears. Although rare, these malignant tumors can be diagnosed by the cytomorphological characteristics, and should be included in the differential diagnoses of breast neoplasms.