Do clinical and radiologic features help predict malignancy of B3 breast lesions without epithelial atypia (B3a)?

To evaluate excision histology outcome of B3a lesions diagnosed at imaging-guided core biopsy and assess whether clinical and radiologic features may predict upgrade to malignancy.

A total of 153 B3a lesions (74 papillomas, 51 radial scars and 28 fibro-epithelial lesions) that underwent surgical excision were assessed. PPV for malignancy in all B3a lesions and specific for each sub-category was evaluated. Multivariate analysis was conducted to identify association between clinical (age, family or personal history of breast cancer, symptoms), diagnostic findings (imaging modality, lesion size, final BI-RADS category) and final excision outcome.

Eleven (7%) of 153 B3a lesions were upgraded to malignancy. All carcinomas diagnosed on excision were non-high grade DCIS. Following features were significantly associated with malignancy: lesions identified only on mammography (3/21; 14%), both mammography and ultrasound (7/44; 16%), lesion size > 10 mm (10/74; 13.5%) and BI-RADS category 4-5 (8/29; 27.6%). The absence of residual microcalcification after biopsy was associated with decreased risk for malignancy (15/16[93.7%]; p = 0.0297). Lesion size > 10 mm (OR = 9.3832; 95%; p = 0.0398) and BI-RADS category 4-5 (OR = 12.6004; 95%; p = 0.0006) were found to be independent predictors of upgrade to malignancy.

B3a lesions are associated with low risk of malignancy at excision. Lesion size > 10 mm and BI-RADS 4-5 category may represent useful predictors of upgrade to malignancy.