Breast masses: US-guided fine-needle aspiration biopsy.

Real-time ultrasonography (US) was used to guide fine-needle aspiration biopsy of 111 breast masses and three axillary lymph nodes. The masses included 51 (45%) nonpalpable lesions. Two different guidance techniques were used, with satisfactory results. Lesions less than 1 cm in diameter could be accurately aspirated, and the method allowed quick and accurate cytologic characterization of solid breast masses. The sensitivity of the cytologic diagnosis of malignancy was 92%, and the specificity was 93%. US-guided fine-needle aspiration biopsy of breast masses should be routinely performed, since it can lead to earlier and cost-effective diagnosis of breast carcinoma at virtually no risk. Because of the accuracy of real-time US guidance, negative cytologic findings (i.e., satisfactory smears with benign cells) should be considered highly reliable in ruling out malignancy.