Isolated Intracranial Osteoblastic Meningioma

Osteoblastic meningioma is a subtypes of meningioma. Intracranial isolated osteoblastic meningioma is extremely unusual. We reported a case of osteoblastic meningioma in the right frontal region in a 15-year-old girl who presented with repeated unconsciousness for 20 days. Computed tomography (CT) revealed a well-defined calcified mass with CT value of 802.5 HU in the right frontal region next to the midline. Magnetic Resonance Imaging (MRI) showed a 4x4x3 cm mass, appearing hypointense on both T1 and T2-weighted imaging and heterogeneous enhancement on contrast-enhanced imaging. A right frontal craniotomy via coronal approach was performed and a bony mass was found in the inferior frontal lobe without attachment of cerebral falx. Pathological examination of the neoplasm was osteoblastic meningioma. Due to its rarity, osteoblastic meningioma was usually misdiagnosed preoperatively. After reviewing related literature, we made differential diagnosis between central nervous system tumors with ossification or calcification and announced that intracranial well-defined calcified mass, even without attachment of convexities or Sylvian fissure, should also be considered as osteoblastic meningioma before operation.