Nonpalpable, well-defined, probably benign breast nodule: management by fine-needle aspiration biopsy and long-interval follow-up mammography

The management of nonpalpable, well-defined breast nodules by short-interval, 6-month follow-up mammography is widely accepted. We have, however, been managing these type of lesions with fine-needle aspiration biopsy (FNAB), guided by sonography or stereotaxic approach, in order to reduce the number of follow-up mammograms. We recommended surgical biopsy only in cases with malignant or suspicious cytology. Patients with benign cytology or inadequate sample were included in a 12-month-interval mammography surveillance program. In the series we present, two carcinomas were diagnosed among 145 lesions (1.38 %). Both had shown malignancy in FNAB. Another two cases, suspicious of malignancy in FNAB, finally resulted benign in histology. The remaining 141 nodules, monitored for at least 2 years, or surgically removed at the patient's request, have not shown signs of malignancy, regardless of a diagnosis of either benign or inadequate sample in FNAB. Sensitivity and negative predictive value of FNAB have therefore been 100 % in this series. No notable differences were observed between stereotaxic and sonographic guidance, except the percentage of inadequate samples (20.3 % by sonography; 25.9 % by stereotaxic sampling). We conclude that stereotaxic or sonographic FNAB is a very accurate diagnostic method in lesions of this type, allowing long-interval surveillance of the nodules with nonsuspicious cytological results.