Calcified Spinal Meningioma: A Lurking Danger

Tumors of the spine with an intradural location have an incidence ranging from 3 to 10 per 100,000 persons per year, and intradural extramedullary tumors account for two thirds of all intraspinal neoplasms. Among these, spinal meningiomas account for 25%–46% of all spinal cord tumors. They develop from the arachnoid cells that differentiate from neural crest cells and, like cerebral meningioma, they have a slow-growing behavior. Although spinal meningiomas are not uncommon, calcified spinal meningioma is rare in spinal location. Calcified meningioma manifests with extensive matrix and tends to infiltrate the surrounding structures. It exhibits a growth pattern limited by an incompletely developed intermediate leptomeningeal layer. This pattern makes such a tumor different from the commonly encountered meningioma that develops into a variable interface in the small space confined between the arachnoid and the intermediate leptomeningeal spaces. Because the intraspinal spaces are much smaller than intracranial spaces, symptoms usually appear rapidly compared with intracranial tumors.