Prevalence of shoulder enchondromas on routine MR imaging.

The objective of this study was to examine the prevalence of incidental shoulder enchondromas on routine magnetic resonance (MR) shoulder imaging. Consecutive routine shoulder MR examinations (N = 477) performed for suspected internal derangement were reviewed for the presence of incidental enchondromas. Incidental enchondromas were detected on 2.1% of routine MR shoulder examinations, the vast majority abutting the physeal plate. This prevalence is important to appreciate, in order to form a meaningful differential diagnosis of pathologic proximal humerus lesions.