Department of Radiology, Asan Medical Center, University of Ulsan, College of Medicine, Korea. jmpark@amc.seoul.kr
Published online: June 1, 2003.
ABSTRACT
PURPOSE: We evaluated the effectiveness of ultrasonography (US) in differential diagnosis of nonpalpable breast nodules. MATERIALS AND METHODS: From January 2000 to June 2001, US-guided fine needle aspiration biopsy (FNAB) was performed in 610 nonpalpable breast nodules from 511 patients. Pre-biopsy US diagnosis was divided into 311 benign and 299 non-benign (malignant and indeterminate) categories. Diagnostic accuracy of Pre-biopsy US was calculated according to the size of lesion. All lesions were pathologically diagnosed by US-guided FNAB while excisional biopsy was performed in 12 cases. RESULTS: Overall, 136/143 FNAB-proven malignant nodules (95.1%) and 304/467 FNAB-proven benign nodules (65.1%) were correctly predicted by US. The overall diagnostic accuracy was 72.1% while the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were highest for the nodules sized between 1-2cm in the longest diameter (98.1%, 70.1%, 47.7%, 99.2% and 76.2%, respectively). The number of false negative malignancies were seven (4.9%); four of them, smaller than 1cm. False negative malignancies showed ovoid or round in shape, well defined margin and homogeneous echogenecity. Meanwhile, frequent US findings of indeterminate nodules included ill-defined margin, microlobulated border, angular margin and marked hypoechogenecity; however, 86% of them were proved to be benign. CONCLUSION: Ultrasonography is an effective diagnostic method in differential diagnosis of nonpalpable breast nodules, especially for 1-2 cm sized nodules. However, US characteristics suggestive of malignacy were also frequently seen in benign lesions.