Fine-needle aspiration cytology of nonpalpable breast lesions: US versus stereotaxic guidance.

The authors evaluated ultrasound (US)-guided fine-needle aspiration cytology (FNAC) in 270 patients with suspicious findings at mammography. FNAC with a 10-MHz transducer and real-time scanner was performed when a lesion seen mammographically was unequivocally depicted at US. The needle was inserted with variable obliquity to the scanning plane. Stereotaxically guided FNAC was performed when lesions were not visible at US. High suspicion at mammography and positive cytologic reports led to surgical biopsy. Of the 270 lesions, 120 (44.4%) were visible at US. Opacities were the most frequently visualized lesions. Inadequate samplings were most frequently reported for opacities with smooth margins. Differences in accuracy and inadequacy rate between the two modalities were not significant. Cancer was surgically confirmed in 86 of 110 cases. The other 160 lesions were considered benign, and mammographic follow-up in 120 has shown no change. Because FNAC with US guidance was faster and less expensive, it is recommended as the technique of choice in lesions detectable with US.