Fibrous Dysplasia of Bone and Primary Hyperparathyroidism

Two patients with monostotic fibrous dysplasia had hyperparathyroidism. One of the patients had frank hypercalcemia; the second patient had hyperparathyroidism with near normal serum calcium values. Both had chief cell adenomas at surgery. Removal of the parathyroid adenomas did not appear to influence the course of fibrous dysplasia. Associated hyperparathyroidism may occur in 5% to 10% of patients with fibrous dysplasia. A similar association has been observed in patients with neurofibromatosis and parathyroid adenomas. The possible mechanisms responsible for the association of hyperparathyroidism and fibrous dysplasia are discussed.