Ultrasound-guided fine-needle aspiration of nonpalpable breast lesions. Cytologic and histologic findings.

Between 1989 and 1992, 651 nonpalpable breast lesions in 586 patients were aspirated using the ultrasound-guided technique at M.D. Anderson Cancer Center. Cytologic diagnoses were as follows: malignant, 167; suspicious, 30; benign, 211; cysts, 168; atypical ductal hyperplasia, 4; and insufficient for diagnosis, 71. In all cystic and most benign lesions, fine-needle aspiration (FNA) confirmed the benign clinical findings, and surgery was not performed. Of the 483 solid lesions, 254 were subsequently treated surgically, either because of suspicious mammographic or sonographic findings or because of positive or suspicious cytologic findings. The cytologic diagnoses in these cases were as follows: 132 (52%) malignant, 65 (25%) benign, 26 (10%) suspicious, 4 (2%) atypical, and 27 (11%) insufficient for diagnosis. The sensitivity of ultrasound-guided FNA for the diagnosis of malignant lesions was 91%, specificity 77%, and overall accuracy 84%. There were four (2%) false-negative results. Diagnostic failures were attributed to the small size of the lesions, histologic type, and inexperience in localization and cytologic interpretation of tubular carcinoma. One (1%) false-positive diagnosis was made (atypical ductal hyperplasia misdiagnosed as carcinoma). The authors' findings indicate that ultrasound-guided FNA offers a reliable and simple alternative to open biopsy of nonpalpable breast lesions. The efficacy of this technique depends primarily on accurate localization of the biopsy needle and on skillful cytologic interpretation of certain breast lesions.