Primary intraventricular osteosarcoma in a 3-year-old boy: report of a case and review of literature.

Introduction: Extraskeletal osteosarcoma (ExOS) is a rare and well-known entity. Three to 4% of ExOSs occur in the head and neck region but anecdotally in the central nervous system (CNS). Primary intracranial osteosarcoma (PIOS) can originate from the skull, brain parenchyma, or meninges.