Intralesional resection and autologous fibular graft reconstruction for a giant cell tumor of the fourth metacarpal with a secondary aneurysmal bone cyst: a case report.

Introduction and importance: Giant cell tumor (GCT) of bone rarely involves the metacarpal bones. Secondary aneurysmal bone cyst (ABC) changes arising in association with GCT create distinct diagnostic and therapeutic challenges in this uncommon skeletal location. Case presentation: A 21-year-old right-hand-dominant female presented with progressive right fourth metacarpal pain and swelling following minor trauma. Radiographs and magnetic resonance imaging (MRI) demonstrated an expansile osteolytic lesion with cortical thinning and internal fluid-fluid levels suggesting GCT with secondary ABC changes. Preoperative chest radiography showed no evidence of pulmonary metastasis. Intralesional resection was performed while preserving the metacarpal head articular surface. Biological reconstruction was achieved using a non-vascularized autologous fibular graft stabilized with Kirschner wires. Histopathological examination confirmed GCT associated with secondary ABC changes and excluded telangiectatic osteosarcoma. At the 6-month follow-up, the patient demonstrated satisfactory graft incorporation, excellent hand function, and no evidence of local recurrence or pulmonary metastasis. Clinical discussion: Hand GCTs exhibit more aggressive behavior and higher recurrence rates than those in conventional skeletal locations. Differentiating secondary ABC from primary ABC and from telangiectatic osteosarcoma is essential, as treatment strategies and oncological implications differ significantly. Conclusion: Intralesional resection followed by biological reconstruction using a non-vascularized autologous fibular graft preserves hand function while achieving satisfactory early local disease control in selected patients.