Needle localization in occult breast lesions.

A series of 211 women underwent 211 preoperative needle localizations of nonpalpable breast lesions. All mammographic, operative, and pathological data were reviewed. Carcinoma occurred in 10%. Seventeen (81%) were invasive, and four (19%) were noninvasive. Forty-three percent of the cancers were minimal carcinoma (in situ or an invasive cancer measuring less than 5 mm in size with negative axillary nodes), and 48% were less than 1 cm. Overall, metastasis to axillary lymph nodes occurred in 10%. The mammographic findings of microcalcifications occurred in 81% of the malignant group and in 33% of the benign group. The combination of microcalcifications in association with an irregular density was only found in the malignant group. We conclude that 1) needle localization enables the early detection of stage I breast carcinoma and 2) the mammographic findings of microcalcifications in association with an irregular density occur only with malignancy in this series.