EVIDENCE FOR CLONAL SPREAD IN THE DEVELOPMENT OF MULTIPLE MENINGIOMAS

Meningiomas are common intracranial tumors that arise from the arachno id cells of the meninges. Occasionally patients develop multiple menin giomas. Because the underlying mechanism of multiple meningioma format ion is unknown, the authors examined the pattern of X chromosome inact ivation in multiple meningiomas. Fifteen intracranial meningiomas were resected in four patients with multiple meningiomas to determine whet her the tumors in patients with multiple meningiomas originate from a common progenitor cell or arise independently. Specimens were examined using polymerase chain reaction assays to detect the pattern of X chr omosome inactivation. In each patient, all tumors showed inactivation of the same X chromosome, suggesting that tumors arose from the same c lone of cells (p < 0.0005). The authors conclude that multiple meningi omas arise from the uncontrolled spread of a single progenitor cell.