Chondrosarcoma arising from long-standing Dysplasia Epiphysealis Hemimelica of the proximal humerus: A case report

Dysplasia Epiphysealis Hemimelica (DEH), or Trevor’s disease, is a rare, nonhereditary skeletal disorder involving abnormal cartilaginous overgrowth of the epiphysis. To our knowledge, malignant transformation has not been previously documented. We report a unique case of chondrosarcoma arising from a DEH lesion in the proximal humerus nearly 30 years after the initial diagnosis. The patient was treated with wide resection and reconstruction using a proximal humeral replacement with a reverse-constrained total shoulder arthroplasty. This case highlights the need for long-term follow-up in patients with DEH, especially when new symptoms suggest possible malignant transformation.