Intramammary lymph nodes: cytologic findings and implications for fine-needle aspiration cytology diagnosis of breast nodules.

The recognition of intramammary lymphoid proliferations is important because smears of these proliferations would be judged as insufficient by several of the published criteria for specimen adequacy. Alternatively, some might be confused with medullary carcinoma of the breast or adenocarcinomas with a "single-cell" pattern. We found 19 intramammary lymphoid proliferations in a series of 887 fine-needle aspirates of palpable breast nodules. Six were lymphomas and 13 were benign intramammary lymph nodes. Smear cellularity ranged from scant to high, but in all cases, lymphocytes dominated the cell population. The cytology of intramammary lymph nodes and lymphoma did not differ from those occurring at other sites.