[Intrathecal dissemination of meningiomas; a case report].

A case of the cytologically verified intrathecal dissemination of benign meningiomas was reported. A 36-year-old man was admitted to our hospital because trans-sphenoidal surgery was planned for the repair of CSF rhinorrhea caused by a recurrent pituitary adenoma. The CT scan demonstrated incidental multiple tumors spread throughout in the pontomedullary and ambient cisterns. The head and spinal MRI showed more than fifteen small tumors in the posterior fossa and the thoracic spinal canal. CSF cytology revealed benign fibroblastic or meningotheliomatous meningioma with whorl formation and psammoma body. Several comments were made on the mechanism of the intrathecal dissemination of the meningiomas.