Fine needle aspiration biopsy of breast carcinoma in pregnancy and lactation

To delineate the cytomorphologic features seen in cancer of the breast during pregnancy and lactation, to compare them to the cytomorphologic parameters in benign conditions and to determine the feasibility of differentiating features of malignant breast carcinoma from those of benign breast lesions during pregnancy.

The study group consisted of pregnant or lactating women with breast carcinoma and with benign breast lesions who underwent fine needle aspiration (FNA) of the breast lesions. The findings of FNA were reviewed, analyzed, tabulated and correlated with the pathologic diagnosis of the breast biopsies.

Eleven patients had malignant cytomorphologic changes, including increased cellularity, multilayering, enlarged and pleomorphic nuclei, single or multiple nucleoli, mitosis and numerous isolated tumor cells. Secretory changes were scanty. The background was foamy and necrotic. FNA of the benign lesions showed a biphasic cell pattern with cohesion; minimal nuclear pleomorphism; single, regular nucleoli; and naked nuclei in a granular background with foamy macrophages. Increased cellularity with nuclear atypia, single cells and a dirty background was seen in benign and malignant conditions.

The main cytologic features that differentiate breast carcinoma from benign conditions during pregnancy and lactation are crowding and overlapping of nuclei, dyscohesion and enlarged, pleomorphic nuclei with irregular nuclear membranes, coarse nuclear chromatin and mitoses. Pregnancy-related hyperplastic changes with atypia can potentially result in a false positive diagnosis of carcinoma.