The contribution of ultrasonography to the differential diagnosis of breast cancer.

Overall consecutive breast abnormalities (259 carcinomas, 1820 benign) examined with breast ultrasonography (US) are reported. US sensitivity, specificity and positive predictive value were 67.6, 97.7 and 81.0%, resp. (the corresponding values were 57.9, 97.9 and 77.2% for palpation, 79.9, 93.5 and 73.7% for mammography, and 97.6, 92.6 and 87.6% for cytology). US sensitivity was unaffected by age, whereas it was strongly influenced by tumor size (pT1-76.1%; pT2-87.1%) and histologic type (intraductal-7.4%; invasive ductal/lobular-83.4%; invasive special types-64.1%). The features of the lesions at US were significantly associated with cancer (irregular margins, posterior acoustic shadowing) or benign lesions (anechoic structure, lateral shadowing, posterior acoustic enhancement) but had a limited diagnostic accuracy. Overall, US visualized 174 (benign-24, suspicious-150) of 188 palpable, and 32 (benign-7, suspicious-25) of 71 nonpalpable cancers. US contribution was determinant to final diagnosis in 4 of 7 cancers, missed at palpation and mammography, but was at least partially responsible for 8 unnecessary biopsies of benign lesions. A negative/benign US report contributed to avoid unnecessary biopsy in 71 suspicious cases at palpation/mammography. Routine US examination of clinical/mammographic abnormalities is recommended for the advantages of US-guided aspiration and to reduce the frequency of unnecessary biopsies.