Magnetic resonance imaging of radial sclerosing lesions (radial scars) of the breast

Purpose: To identify magnetic resonance (MR) imaging (MRI) features of radial sclerosing lesions (RSLs) of the breast.

Methods and materials: The radiologic and pathologic records for 4629 consecutive patients undergoing MR examinations of the breast were retrospectively reviewed. Patients who received a pathologic diagnosis of RSL without atypia or carcinoma at surgical excision were identified. The MR images were evaluated according to the BI-RADS-MRI lexicon by two experienced breast radiologists. The frequency of morphologic and kinetic patterns and of BI-RADS-MRI assessment categories was calculated.

Results: Twenty-nine patients with 29 surgically excised RSL were identified. Nine (31%) RSL were MR-occult; the remaining 20 (69%) RSL presented as masses (10/20, 50%), architectural distortions (5/20, 25%), non-mass lesions (4/20, 20%), and focus (1/20, 5%). Kinetic analysis was performed in 18 RSL: enhancement features were benign in 9 (50%) cases, suspicious in 7 (39%) cases and indeterminate in 2 (11%) cases. Twelve (41%) MR examinations were assessed as suspicious (BI-RADS-MRI 4 and 5), and 17 (59%) as negative (BI-RADS-MRI 1) or benign (BI-RADS-MRI 2 and 3).

Conclusion: RSLs are often visualized on MR imaging. Just as in mammography and sonography, RSL can have variable morphologic and kinetic features, and not infrequently they can mimic invasive carcinoma of the breast.