[Fine-needle cytology and core biopsy of nonpalpable breast lesions. When appropriate?].

The respective roles of fine-needle cytology and core biopsy for the investigation of breast densities and microcalcifications are discussed. For microcalcifications, the type, number, and conditions of development should be taken into account, and the reliability of investigations are directly related to stereotactic visibility, i.e., to advances in digitization. Fine-needle biopsy has been almost completely discarded as a means for investigating microcalcifications but remains useful when performed under ultrasound or stereotactic guidance to investigate densities presumed to be nonmalignant. Doubtful densities are best investigated by core biopsy.