Ossification in an extra-intradural spinal meningioma-pathologic and surgical vistas.

Background Context: Intradural and intratumorous ossification in spinal meningiomas are rare compared to their cranial counterparts. Extradural extension of the spinal meningioma is not uncommon. To the best of our knowledge, the ossification in an extra-intradural spinal meningioma is not yet reported in the literature.

Purpose: The authors report a rare case of an extra-intradural spinal meningioma with ossification and calcification. The review of literature including the surgical challenges and the histologic variations as well as histogenesis of the ossified spinal meningioma is discussed.

Study Design: Case report and review of the literature.

Methods: A 61-year-old woman presented with complaints of numbness and weakness for 3 years, and gait disturbances for 6 months. Magnetic resonance imaging revealed a mass compressing the spinal cord at the T4 level.

Results: Complete resection of the tumor was achieved with coagulation and partial resection of the dura. Histopathological examination demonstrated a psammomatous spinal meningioma with intratumorous and intradural mature lamellar bone formation, complete with marrow and hematopoietic cells. The patient is asymptomatic at 3-year postoperative follow-up.

Conclusions: Despite adherence of the ossified mass to the dura, arachnoid, and spinal cord, complete atraumatic resection of the mass was possible with favorable surgical outcome. In addition to calcification as a likely forerunner of ossification in the psammomatous subtype of meningioma, metaplastic differentiation of neoplastic cells to osseous and hematopoietic component might play a crucial role.