Proximal Humerus Ewing Sarcoma: Technical Challenges and Strategies for Bone Defect Reconstruction.

INTRODUCTION: The proximal humerus is the most common site for primary malignant tumors of the upper limb, with chondrosarcoma, Ewing sarcoma, and osteosarcoma being the most frequent malignancies. Conservative treatment presents significant challenges regarding oncological resection due to the complex neurovascular anatomy and subsequent bone defect reconstruction. CASE REPORT: We report the case of a 29-year-old North African male managed for Ewing sarcoma of the proximal humerus. Locoregional staging showed tumor extension to the triceps, but no involvement of the deltoid, rotator cuff, or neurovascular bundle. Distant staging revealed pulmonary nodules. The patient underwent neoadjuvant chemotherapy with complete resolution of pulmonary nodules and soft-tissue extension. The patient underwent tumor resection with reconstruction using a non-vascularized fibular graft and fixation with an anatomical plate and intramedullary pin, achieving good functional outcomes (Musculoskeletal Tumor Society Score [MSTS] of 80%) and no recurrence at 30 months of follow-up. CONCLUSION: Limb-sparing management of proximal humeral tumors faces several challenges: achieving oncological resection due to the complex musculotendinous and neurovascular anatomy of the shoulder, and the subsequent challenge of reconstructing the bone defect. Indications and functional outcomes depend heavily on the involvement of the deltoid, axillary nerve, glenoid, and rotator cuff. Biological reconstruction represents a valuable alternative to prosthetic replacement in appropriately selected cases.