An Unusual Presentation of Giant Cell Tumor of the Tibia in a Skeletally Immature Patient.

Introduction: Giant cell tumors (GCTs) are locally aggressive tumors that principally affect the epiphysis of long bones. Histologically, these tumors consist of three types of cells: Osteoclast-like multinucleated giant cells, round mononuclear cells resembling mononucleocytes, and spindle-shaped round fibroblast-like stromal cells. Radiographically, the tumors appear osteolytic and radiolucent without a sclerotic border. The tumor rarely occurs in pediatric age group. Its incidence in pediatric patients varies from 1.8 to 7.5%. Case Report: A 15-year-old girl presented to us with the complaints of pain in the left knee of 3months' duration and inability to squat. Radiographic imaging was done which showed lytic lesion involving the proximal tibia and showing cortical destruction. The lesion was graded as a Campanacci Grade 3 tumor. The patient was taken up for surgery and an extended curettage was performed, and the cavity was packed with bone cement. The patient was asymptomatic at the end of 18-month follow-up and was continuing her normal daily activities. Conclusion: GCT of the bone is extremely rare in skeletally immature patients. This particular case highlights the need for keeping the diagnosis of GCT at the periphery of one's vision when dealing with pediatric patients presenting with osteolytic lesion at the epimetaphysis of long bones.