Sonographically guided needle biopsy of nonpalpable breast lesions.

This article describes the techniques of sonographically guided fine-needle aspiration (FNA) and core-needle biopsy (CNB) of nonpalpable breast lesions. Virtually any nonpalpable breast lesion that is clearly demonstrated on sonograms can be sampled with a needle under ultrasound guidance. Advantages of ultrasound-guided FNA include its pinpoint accuracy, the excellent tolerance by patients, and the ability to aspirate or inject fluid or air. Advantages of ultrasound-guided CNB include a near 100% tissue recovery rate even in fibrous masses, the ability to assess the invasiveness of a cancer, and the fact that tissue cores are readily interpreted by any pathologist. In institutions in which an expert cytopathologist is available, FNA is often used as a first-line biopsy technique, with CNB being reserved for situations in which FNA cannot provide a definitive answer to the question asked. In most institutions, however, CNB has become the standard for percutaneous needle biopsy of breast masses, and sonography has replaced stereotaxy as the standard guidance technique for nonpalpable masses.