Fine needle aspiration cytology of "minimal" breast cancer.

The value of fine needle aspiration (FNA) cytology in the diagnosis of "minimal" breast cancer was studied. Sixteen (76.2%) of 21 cases of invasive breast cancer less than 1.0 cm in diameter and 14 (73.3%) of 19 cases of noninvasive breast carcinoma were given a positive diagnosis by FNA cytology. One "suspicious" and the five false-negative diagnoses occurred in cases of invasive carcinoma; the reasons were considered to be either a faulty technique of needling the tumor or the presence of prominent fibrosis in the tumor. In noninvasive carcinoma, atypical cells were misdiagnosed in two of the five smears that had been originally reported as negative. The results of the retrospective analysis showed that FNA cytology had a higher accuracy in the diagnosis of small lesions than did radiologic and echographic criteria, and FNA cytology was thus used as the main criterion for deciding on the necessity for preoperative surgical biopsies.