Metastatic malignant meningioma.

The onset of a rapidly progressive abducens and trigeminal neuropathy, third-order neuron Horner's syndrome, and decreased lacrimation clinically suggest a malignant lesion at the base of the middle cranial fossa, commonly a metastatic process. A case is reported in which computed tomography and magnetic resonance imaging failed to image the lesion but a bone scan clearly depicted the abnormal area. A malignant meningioma (en plaque) was evident on biopsy, and pulmonary metastases later ensued. Common histological patterns of meningioma (often thought of as a benign tumor) include meningothelial, fibrous, and transitional types. The association of cellular atypia, nuclear pleomorphism, marked mitoses, and brain invasion warrants the designation of malignant meningioma. The incidence of malignancy in meningioma ranges from 2 to 10% with reported metastases occurring in 0.1%.