Fibrous dysplasia associated with primary hyperparathyroidism in the absence of the McCune-Albright syndrome: Tc-99m MIBI and Tc-99m MDP findings.

Abstract

Fibrous dysplasia is a slowly progressive bone disorder in which normal bone is replaced by abnormal fibroosseous tissue. The isolated occurrence of fibrous dysplasia or hyperparathyroidism is a common finding. However, fibrous dysplasia associated with primary hyperparathyroidism without the McCune-Albright syndrome has rarely been reported. Tc-99m MDP bone scintigraphy is a useful tool for the diagnosis of fibrous dysplasia. Increased uptake of Tc-99m MIBI in fibrous dysplasia has not been reported. The authors describe a rare case of fibrous dysplasia associated with primary hyperparathyroidism without the McCune-Albright syndrome in which Tc-99m MIBI scintigraphy was compared with the findings of Tc-99m MDP bone scintigraphy. The Tc-99m MDP study showed intensely increased uptake in the fibrous dysplasia lesions. Early Tc-99m MIBI imaging showed increased uptake in the same lesions noted on Tc-99m MDP bone scintigraphy. However, 2-hour delayed images revealed washout of Tc-99m MIBI, in contrast to radionuclide retention with Tc-99m MDP.