Multiple brown tumors in parathyroid carcinoma mimicking metastatic bone disease.

An unusual case of multiple brown tumors due to parathyroid carcinoma is reported. The patient presented with lower leg pain. Plain radiographs demonstrated multiple lytic lesions of the lower legs and a Tc-99m MDP bone scan depicted multiple areas of increased uptake suggesting skeletal metastases. Tc-99m sestamibi tumor scintigraphy showed multiple sites of tumor uptake in bones and a large area of increased uptake with a cystic component in the right lower pole of the thyroid gland. An open biopsy from the right tibial lesion revealed a brown tumor. A large parathyroid carcinoma with a necrotic cyst was removed. After parathyroidectomy and right thyroid lobectomy, the patient became free of bone pain and serum PTH levels normalized. A 9-month follow-up Tc-99m MDP bone scan demonstrated less intense uptake in the pelvis, tibia, and fibulae. Nine-month follow-up tumor imaging with Tc-99m MIBI revealed disappearance of the preoperative uptake of multiple brown tumor.