Nasopharyngeal Meningioma

Epidemiology

Meningiomas make up approximately 20% of all central nervous system tumors. They are benign tumors arising from arachnoid cells. However, 15 to 20% of all meningiomas extend outside the cranial cavity or spine. Extracranial tumors may be found in the temporal bone, orbit, sinonasal cavity, nasopharynx, and parotid gland. Meningiomas are most commonly found in the fifth decade of older patients and show a predilection for females. Meningiomas are rare in children.

Clinical Findings

The clinical signs and symptoms depend on the manner in which the meningioma reaches the nasopharynx. Tumor spreading through the superior orbital fissure and extending along the pterygopalatine fossa into the anterior nasopharynx may produce diplopia, maxillary nerve compression, and nasal symptoms. Large meningiomas reaching the nasopharynx from the jugular foramen may have lower cranial nerve palsies.

Pathology

Intracranial and extracranial meningiomas have identical histologic features. However, extracranial tumors tend to be less well circumscribed and show a greater propensity to invade surrounding structures. Malignant degeneration is rare. Immunochemistry tests that are typically positive include S-100 protein antigen, vimentin, and epithelial membrane antigen (EMD).