Risk of neoplastic transformation in asymptomatic radial scar. Analysis of 117 cases

BACKGROUND: Radial scar (RS) is a benign breast lesion but a variable percentage of cases are associated with atypical epithelial proliferations and cancer. Previous studies have shown that patient age and the size of RS are correlated to a potential neoplastic transformation. METHOD: We collected 117 asymptomatic patients with suspected RS following a mammogram, histologically confirmed. The clinical, pathological and immunophenotypical analysis is reported. The cases are subdivided into three different groups: (1) RS "Pure", without epithelial atypia; (2) RS associated with epithelial atypical hyperplasia; (3) RS with cancer. RESULTS: "Pure" RS was detected in 55 patients (47\%); the mean age was 48.1 years and the mean size 0.94 cm. RS associated with atypical epithelial hyperplasia was identified in 25 cases (21\%) with a mean age of 53.1 years and a mean size of 0.98 cm. Carcinoma in RS was observed in 37 cases (32\%); the mean age was 55.5 years and the mean size was 1.16 cm. The mean age was statistically significant (P = 0.004) in separating RS with cancer from the two other RS groups. The size of RS was not sufficiently statistically significant (P = 0.2) to differentiate the risk. Atypical lesions and cancers showed a morphology and marker of low-grade aggressiveness. CONCLUSION: RS seems to represent a natural model of carcinogenesis starting from a proliferative lesion in patients of less than 50 years of age and developing into an atypical and later into a carcinomatous lesion. The fact that most carcinomas arising in RS are low grade also favors this hypothesis. All RS should be excised.