Fine-needle aspiration of mammary lobular carcinoma in situ and atypical lobular hyperplasia.

Cytologic features of fine-needle aspirations (FNAs) of the breast from three patients with either lobular carcinoma in situ (LCIS) or atypical lobular hyperplasia (ALH) are described and compared with those in six patients with infiltrating lobular carcinoma (ILC). FNAs of LCIS and ALH were characterized by loosely cohesive cell groups composed of uniform cells with frequent eccentric nuclei, minimal nuclear atypia, and occasional intracytoplasmic lumina. FNAs from ILC had some overlapping features with ALH and LCIS but were generally more cellular and had a higher proportion of noncohesive single cells with more nuclear atypia and pleomorphism. Intracytoplasmic lumina were consistently found in invasive and noninvasive lobular lesions and may represent the most useful cytologic clue for their recognition. FNAs with the above features are atypical and suggestive of ALH or LCIS. Excisional biopsy should be performed in such cases to confirm the presence of ALH or LCIS and to evaluate for ILC.