Beta-Catenin Positive Giant Cell Tumor of Bone with Pathological Fracture Treated with Neoadjuvant Denosumab Therapy for Visualizing Extraskeletal Lesions.

INTRODUCTION

Giant cell tumors of bone (GCTBs) are locally aggressive tumors that can induce pathological fractures. Previous reports suggest that denosumab induces intratumoral ossification in β-catenin positive GCTB. However, its effect on the complete resection of GCTB with extraskeletal lesions remains unclear.

CASE PRESENTATION: A 45-year-old woman with a pathological fracture of the left distal femur was diagnosed with GCTB based on the biopsy findings, which revealed both H3.3 G34W and nuclear β-catenin positivity. Eight courses of neoadjuvant denosumab therapy were administered to visualize the extraskeletal lesions; subsequently, en bloc resection with megaprosthetic reconstruction was successfully performed. Pathological examination revealed intratumoral ossification without osteoclastic giant cells. Two years after the surgery, no evidence of local recurrence was recorded.

CONCLUSION

Neoadjuvant denosumab therapy is an effective approach for managing β-catenin positive GCTB with pathological fractures as it promotes intratumoral ossification and facilitates complete resection of GCTB, including extraskeletal lesions.