Proximal Tibial Giant Cell Tumor in a Skeletally Immature Child: A Diagnostic Dilemma and Review of the Literature.

Introduction: Giant cell tumor (GCT) of bone is a benign, locally aggressive neoplasm that primarily involves the epiphysis of long bones in skeletally mature individuals. It is extremely rare in skeletally immature patients. We report a rare case of proximal tibial GCT in a 7-year-old girl with a pathological fracture and metadiaphyseal extension, highlighting diagnostic considerations and long-term outcomes. Case Report: A 7-year-old girl presented with pain, swelling, and deformity of the left upper leg following trivial trauma. Radiographs and non-contrast computed tomography scan demonstrated an expansile, eccentric osteolytic lesion in the proximal tibia metadiaphyseal region with a fracture. The patient underwent intralesional curettage, autologous cancellous bone grafting supplemented with synthetic graft, and stabilization with external fixation. Histopathological examination confirmed the diagnosis of GCT. At 4-year follow-up, the patient remains asymptomatic without deformity, limb-length discrepancy, or recurrence. Conclusion: GCT should be considered in the differential diagnosis of eccentric osteolytic lesions in the metadiaphyseal region of long bones in the immature skeleton, even when imaging mimics other benign entities such as aneurysmal bone cyst or non-ossifying fibroma. Adequate curettage and reconstruction can result in excellent functional outcomes.