C. Sinonasal meningioma
Pathology results showed characteristic whorled meningothelial arrangement of cells with round to oval spindle-shaped nuclei, low mitotic activity, and presence of intranuclear cytoplasmic inclusions and psammoma bodies. Pertinent immunohistochemistry stains included positive epithelial membrane antigen, and negative cytokeratins, smooth muscle actin and synaptophysin; S100 may be weakly positive. Pathology results were confirmatory for sinonasal meningioma.
Meningiomas are the most common primary central nervous system tumors and account for approximately one-third of all primary brain and spinal tumors.1 Risk factors for meningiomas include ionizing radiation exposure, genetic predisposition, obesity, and hormonal factors (as suggested by a higher incidence in postpubertal women compared with men). Meningiomas are classified by the World Health Organization (WHO) with the general basis of WHO grade 1, 2, or 3 as being benign, atypical, or malignant tumors, respectively.2