A Rare Case of Masquerading Chondrosarcoma with Pathological Fracture of Neck of Femur - A Case Report.

Introduction: Chondrosarcoma is the second most common primary malignant tumor accounting for 20-27% of these. These are malignant cartilaginous tumor found most commonly in the pelvis, followed by the proximal femur. Perivascular epitheloid cell tumor (PEComa) is a rare mesenchymal neoplasm. These tumors all share a distinctive cell type, the perivascular epithelioid cell (which has no known normal tissue counter - part).These are post commonly found in visceral sites such as gastrointestinal and uterus, in retroperitoneum and abdominal pelvic sites, rarely affecting skeletal system. Case Report: A 45-ycar-old female was presented in the orthopedic outpatient department with a 2-year history of pain and swelling in her right hip with recent weight-bearing difficulties for 1 week after trivial slip and fall. X-rays revealed a lytic lesion in her right proximal femur along with neck of femur fracture. Biopsy revealed perivascular epitheloid tumor. Diagnosed with primary bone PEComa without metastasis in the right proximal femur, the patient underwent wide local excision and reconstruction using a mega-prosthesis.Post-operative histopathological evaluation surprisingly identified a low-grade chondrosarcoma, but with clear surgical margins. Conclusion: This case highlighted an unusual diagnostic discrepancy between pre-operative and post-operative evaluations. Nonetheless, the adopted strategy was effective, allowing the patient to resume daily activities. Surgeons should remain aware of the potential for primary bone tumors to masquerade as atypical tumors.