Percutaneous core needle biopsy of radial scars of the breast: When is excision necessary?

OBJECTIVE. This study was conducted to evaluate the outcome of cases of radial scar diagnosed by percutaneous core needle biopsy. MATERIALS AND METHODS. Of 198 nonpalpable lesions diagnosed with radial scars found at core needle biopsy, 157 lesions constituting the study group had undergone surgical excision (n = 102) or mammographic surveillance after biopsy for at least 24 months (median, 38 months; n = 55). Mammographic lesion type, lesion size, biopsy guidance method, biopsy device, number of specimens per lesion, and presence of atypical hyperplasia at percutaneous biopsy were retrospectively analyzed. Results were compared with histologic findings at surgery or mammographic findings during surveillance. RESULTS. Carcinoma was found at excision in 28% (8/29) of lesions with associated atypical hyperplasia at percutaneous biopsy and 4% (5/128) of lesions without associated atypia (p < 0.0001). In the latter group, carcinoma was found at excision in 3% (2/60) of masses, 8% (3/40) of architectural distortions, and 0% (0/28) of microcalcification lesions. Malignancy was missed in 9% (5/58) of lesions biopsied with a spring-loaded device and in 0% (ono) of lesions biopsied with a directional vacuum-assisted device (p = 0.01); and in 8% (5/60) of lesions sampled with less than 12 specimens per lesion and 0% (0/68) sampled with 12 or more specimens (p = 0.015). Lesion type, maximal lesion diameter, and type of imaging guidance (stereotactic or sonographic) were not significant factors in determining the presence of malignancy. CONCLUSION. Diagnosis of radial scar based on core needle biopsy is likely to be reliable when there is no associated atypical hyperplasia at percutaneous biopsy, when the biopsy includes at least 12 specimens, and when mammographic findings are reconciled with histologic findings. When the lesion diagnosed by core needle biopsy as radial scar does not meet these criteria, excisional biopsy is indicated.