Rare Tumors

Meningiomas are mostly benign tumors that arise from arachnoid cap cells of the meninges. They occur most frequently during the fifth or sixth decades of life and account for 15–25% of all primary intracranial neoplasms (Germano et al. 1994). These tumors are rare in children and adolescents, comprising only 1–3% of all meningiomas (Tufan et al. 2005) and less than 5% of all pediatric intracranial neoplasms (Di Rocco and Di Rienzo 1999; Tufan et al. 2005; Amirjamshidi et al. 2000). Unlike adult series, in which the female-to-male ratio is 2:1, most series on pediatric meningiomas report either a male preponderance (Sano et al. 1981; Baumgartner and Sorenson 1996; Erdincler et al. 1998) or no gender predilection (Di Rocco and Di Rienzo 1999; Amirjamshidi et al. 2000). Most children with meningiomas are diagnosed in the fi rst or second decades of life (Erdincler et al. 1998), and median age at presentation is 13 years (Greene et al. 2008). Although many of these tumors develop spontaneously, risk factors include prior radiation therapy and diagnosis of neurofi bromato-sis type 2 (NF2). Patients with NF2 have mutations on chromosome 22 that lead to the dysfunction of the NF2 tumor-suppressor gene (Gutmann et al. 1997). The incidence of neurofi bromatosis in children with meningiomas ranges from 13–41% in various series (Deen et al. 1982; Germano et al. 1994; Baumgartner and Sorenson 1996; Erdincler et al. 1998; Amirjamshidi et al. 2000). Patients with radiation-induced or neufi bromatosis-associated men-ingiomas are generally diagnosed at a later age than those with spontaneously occurring tumors (Greene et al. 2008).