Successful treatment of a dedifferentiated chondrosarcoma of the proximal humerus with a hemicortical articular surface sparing allograft: A case report

INTRODUCTION: Dedifferentiated chondrosarcomas are rare and highly malignant tumors that require wide surgical resection. Survival is extremely poor without adequate surgical margins. We present a case of articular sparing surgery of the shoulder for dedifferentiated chondrosarcoma with excellent functional outcomes and no evidence of disease after fifty-six months. PRESENTATION OF CASE: A 29-year-old male was found to have a non-metastatic right proximal humerus dedifferentiated chondrosarcoma. He underwent resection with clear one centimeter margins sparing the medial cortex and the articular surface. Reconstruction of the bone was accomplished using a hemicortical allograft. A dermal allograft was used to help reconstruct the rotator cuff to the allograft bone. At fifty-six months after surgery he has excellent functional range of motion. His current MSTS, Quick Dash, and Constant Shoulder scores are 29, 2.3, and 80, respectively. He has remained free of disease, is back to work without restrictions and is active in outdoor activities. DISCUSSION: Dedifferentiated chondrosarcoma has high recurrence and poor survival rates. Adequate surgical resection is vital for its treatment. Previously described reconstructive techniques have consisted of articular replacement with a prosthesis, allograft, or allograft-prosthetic composites. To our knowledge, this is the first report of an articular sparing reconstruction for dedifferentiated chondrosarcoma with fifty-six month survival and functional outcomes. When possible, sparing the articular surface can provide good functional outcomes that improve over time. CONCLUSION: If adequate surgical margins can be obtained, an articular surface sparing reconstruction of the shoulder can provide effective functional outcomes and an alternative to joint replacement.