Pathologic fracture of the distal femur in osteitis fibrosa cystica simulating metastatic disease.

A 32-year-old woman sustained a minor sliding accident with moderate to severe pain about the left distal thigh and hip and the right shoulder. Radiographs showed marked osteopenia, multiple osteolytic bone lesions, and a pathologic fracture of the left distal femur. Surgical intervention was conducted for the pathologic fracture, and the pathological findings confirmed the diagnosis of primary hyperparathyroidism with osteitis fibrosa cystica. We report this rare case here because it may be mistaken for neoplastic metastatic disease on radiographs and bone scan. The pathologic fracture usually heals and the bone mineral density improves significantly within 6 months after parathyroidectomy.