Meningioma: the role of a foreign body and irradiation in tumor formation.

A case of meningioma is reported. At the age of 18 years, the patient had undergone insertion of a Torkildsen shunt through a posteroparietal burr hole for obstructive hydrocephalus secondary to a tumor of the pineal region, of which no biopsy had been made. After the hydrocephalus was relieved, he underwent irradiation of the tumor. Thirty years later, he was treated for an intracranial meningioma wrapped around the shunt. The tumor followed the shunt in all of its intracranial course. Microscopy disclosed pieces of the shunt tube within the meningioma. The role of a foreign body and irradiation in the induction of meningiomas is discussed, and a comprehensive review of the literature is presented.