A rare case of metabolic bone disease

A 26-year-old female overseas student was admitted to hospital with a fracture of her left humerus following minimal trauma. Biochemical abnormalities included hypercalcaemia, hypophosphataemia, raised alkaline phosphatase, raised parathyroid hormone and undetectable 25-hydroxy-vitamin D. Skeletal X-rays revealed multiple osteolytic lesions in the humerus as well as similar lesions in the femora and pelvis. Magnetic resonance imaging of her left shoulder showed a large soft tissue mass in the proximal humerus. Bone biopsy was reported as consistent with a brown tumour of primary hyperparathyroidism and a sestamibi scan confirmed the presence of a parathyroid adenoma. However, the isotope bone scan was reported as showing features typical of fibrous dysplasia involving multiple sites. The patient subsequently fractured her right femoral shaft, and a femoral nail was inserted. Parathyroidectomy was performed at the same time. Postoperatively she exhibited increased calcium and vitamin D requirements. Coexistence of primary hyperparathyroidism and polyostotic fibrous dysplasia is very rare.