Author(s): A. Amaresh Kumar1, R. Ramesh Kumar2, P. Elamparidhi3
Multiple exostosis (diaphyseal aclasis) is a heritable disorder affecting the endochondral skeleton during the period of growth. It is characterized by thickening and deformity of the growing bone with the formation of numerous cartilage-capped exostoses clustered around the areas of most active growth. Thus, the juxtaepiphyseal regions of the tubular bones, the ribs, pelvis, and scapulae are the most heavily affected areas, while the vertebral bodies, the patellae, and the carpal and tarsal bones are usually unaffected. Hereditary multiple exostosis demonstrates an autosomal dominant inheritance pattern.(1)
A 5-year-old male child presented with a large swelling in his left shoulder. Small swellings were noted in bilateral knee joint, right ankle and also in right humerus. The swelling on the left shoulder was initially small in size which then gradually increased in size. There is a strong family history of similar complaints. Radiographs were performed which showed two well-defined exophytic pedunculated lesions arising from the left scapula along the posterior aspect. On MRI, the lesion shows T2 hyperintensity and T1 hypointensity with cartilage cap covering the entire surface.