Purpose: To correlate cytologic findings of stereotaxic fine-needle aspiration biopsy samples with histologic findings of excised samples of nonpalpable mammographically detected lesions.
Materials and methods: In a retrospective review of 2,988 consecutive stereotaxic fine-needle aspiration biopsy samples of nonpalpable breast lesions obtained within 5 years, 70 samples were categorized as atypical. Excision with needle localization and specimen radiography were performed in all lesions; cytologic findings of aspirates were correlated with histologic findings of excised samples. Histologic findings were the standard of reference.
Results: Of the 70 atypical aspirates, 27 were benign (38%) and 43 were malignant (61%). Both the benign and the malignant lesions had an average size at mammography of 1.1 cm. The nuclear grade was low in 21 (49%), moderate in 16 (37%), and high in six (14%) of the malignant lesions. There were axillary lymph node metastases in four samples (9%).
Conclusion: Although lesions with atypical aspirates usually are benign, to achieve a low prevalence of false-negative diagnoses atypia must be interpreted as potential malignancy.