Spinal meningioma containing bone: a case report and review of literature.

Meningiomas constitute about 25% of primary spinal tumours and 1% to 5% of them are calcified. Ossification is a rare event and is rarely reported. Here, the case of a 40-year-old woman who had dorsal spinal cord meningioma (globular variety) at the T(6) vertebral level is reported; the meningioma showed a nidus of T2 weighting hypointensity on MRI as well as a bony chip inside the tumour intraoperatively. The tumour was successfully resected. Though the aetiology of ossification in the meningioma is not well known, metaplasia of arachnoid cells/dystrophic calcification may be the cause. Ossified meningiomas are more difficult to resect than the usual variety. Hypointensity inside tumour in T2-weighted images of MRI should make the surgeon suspicious of this condition, which may in some cases complicate tumour resection.