Hydatid disease of the distal humerus treated with wide resection and reconstruction with endoprosthesis.

A man in his 40s from a rural area presented with progressive pain and functional limitation of the right arm without trauma. Imaging revealed an aggressive lytic lesion with pathological fracture of the distal humerus. Staging studies excluded other lesions. Percutaneous biopsy confirmed osseous hydatid disease. Preoperative albendazole was administered, followed by wide en bloc resection of a 15 cm humeral segment with preservation of neurovascular structures. Reconstruction was achieved using a modular distal humerus endoprosthesis. Postoperative albendazole continued for 6 weeks. At 12 months, the patient was disease-free, with a painless range of motion from 0° to 120°, full independence in daily activities and a Toronto Extremity Salvage Score of 75. This case demonstrates the importance of considering hydatid disease in the differential diagnosis of lytic bone lesions in endemic areas and supports limb-sparing reconstruction as a viable alternative.