Intracranial meningioma with abnormal localization of bone-seeking radiopharmaceutical: correlation with gross and microscopic pathology.

Meningioma is one of the neoplasms in which there may be extraosseous localization of bone-seeking radiopharmaceuticals. Tumor calcification, calvarial erosion, and the formation of reactive bone have been proposed as the cause of this abnormal tracer localization. We present a patient with a frontal meningioma that was evaluated using 99mTc-methylene-diphosphonate bone scintigraphy, head computed tomography, and skull radiography; the homogeneous density seen in the radiographic studies corresponded to the area of bone-seeking-agent localization shown in the scintigram. At autopsy, bony tissue and a few psammoma bodies were found in the meningioma, and apparently accounted for the bone-tracer localization. There was no calvarial erosion and no formation of reactive bone. If skull-radiographic studies show a homogeneous, radio-opaque lesion with no reactive changes in the adjacent skull, a meningioma showing a localization of a bone-seeking radiopharmaceutical may be predicted to have bone-tissue formation with or without psammoma bodies.