The value of fine needle aspiration cytology in the diagnosis of breast proliferative lesions.

In order to further characterize fine needle aspiration cytology of breast proliferative lesions, we analyzed 723 FNA of patients with palpable breast abnormalities who underwent physical, mammographic and/or echographic examination. In 28 biopsies (3.9%), the final cytologic diagnosis was a proliferative lesion, a group of uncommon breast proliferative diseases not yet explored, in which cytology is sufficiently cellular with plenty of atypical elements but not suspicious of carcinoma. Histologic material was available in 22 cases and represented the basis of this retrospective evaluation. Among the positive proliferative lesions (PPL), 10 cases were infiltrating ductal carcinomas and 1 was a microinvasive carcinoma; whereas for the negative proliferative lesions (NPL), in 8 cases the histologic findings demonstrated fibrocystic changes, in 1 a fibroadenoma and in 1 a cystosarcoma phyllodes. The cytologic criteria utilized to define breast proliferative lesions were the following: increased cellularity, occasional single atypical cells, decreased cellular cohesion, crowded, enlarged and overlapping nuclei with three dimensional groupings with prominent nucleoli and chromatic changes. The cytologic characteristics examined demonstrated that the PPL are characterized by single atypical cells with nuclear alterations such as coarsely granular chromatin with a thick nuclear membrane and numerous prominent nucleoli. These features are common to many malignancies, therefore surgical biopsy confirmation is suggested.