Thallium-201 single photon emission computed tomography imaging of meningioma cells in hyperostosis

Hyperostosis is a well-known bony reaction associated with meningioma. However, it is difficult to determine preoperatively whether meningioma cells have invaded the bone, and if so, the extent of tumor invasion. Preoperative thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was performed in four patients with meningioma and hyperostosis. The presence of meningioma cells in bone biopsy specimens was also investigated using standard histological techniques. 201Tl SPECT revealed increased uptake in three of the four patients. Biopsy specimens from these three patients revealed invasion of the bony lesions by meningioma cells in accordance with the 201Tl SPECT findings. 201Tl SPECT found no abnormal uptake in the other patient, in which there was also no histological evidence of tumor invasion of bone. Preoperative 201Tl SPECT can provide information on bone invasion by meningioma, which will facilitate preoperative planning of the extent of bony resection required at meningioma surgery.