Sonographic features of histopathologically benign solid breast lesions that have been classified as BI-RADS 4 on sonography.

PURPOSE

To describe the sonographic (US) features associated with ultrasonography BI-RADS category 4 lesions that have a benign histopathological outcome.

METHODS

One hundred seventy-two histopathologically proven benign lesions in 169 patients, which had been classified as BI-RADS category 4 with ultrasonography, were retrospectively evaluated. Ultrasonography and histopathology findings were analyzed. The frequency of sonographic findings according to the histopathological diagnosis was determined.

RESULTS

Among the 172 lesions, there were 66 (38%) fibroadenomas, 31 (18%) sclerosing adenoses, 24 (14%) fibrocystic changes, 16 (9%) mastitis/inflammations, 9 (5.5%) intraductal papillomas, 8 (5%) focal fibroses, 4 (2.5%) atypical ductal hyperplasias, 4 (2.5%) fat necroses, 2 (1%) phyllodes tumors, 1 (0.5%) tubular adenomas, 1 (0.5%) epidermal inclusion cysts, and 6 (3.5%) "other benign lesions." The most frequent sonographic findings were heterogeneity, indistinct margin, microlobulation in fibroadenomas; heterogeneity, irregular-indefinite margin, and antiparallel orientation in sclerosing adenosis; heterogeneity, microlobulation, and acoustic shadowing in fibrocystic changes.

CONCLUSIONS

BI-RADS category 4 lesions demonstrate more than one suspicious ultrasonography feature, and biopsy is necessary to diagnose malignancy captured in 33% of lesions in this study. At this time, any lesion with more than one suspicious BI-RADS US feature cannot avoid a diagnostic biopsy.