A primary extraosseous Ewing sarcoma in the cerebellopontine angle of a child: review of relevant literature and case report.

Abstract

We report the occurrence of a primary intracranial extraosseous Ewing sarcoma/peripheral primitive neuroectodermal tumor (EES/pPNET) in the cerebellopontine angle in a child. A 10-year-old girl presented with symptoms and signs of an infratentorial space-occupying lesion that was confirmed by magnetic resonance imaging and followed up by subtotal surgical resection. Tumor cells displayed membranous expression of CD99, and one of the typical translocations of EES/pPNET (chromosome 22) was demonstrated by cytogenetic analysis. The literature regarding the histopathological, molecular, radiological, prognostic, and therapeutic features of intracranial EES/pPNET is reviewed, emphasizing the distinction of this entity from the central PNET. Although exceptionally rare, intracranial EES/pPNET should be considered in the differential diagnosis of lesions in the cerebellopontine angle.