Ependymomas originate from which cells?

• A. Schwann cells
• B. Ependymal cells
• C. Oligodendrocytes
• D. Astrocytes

Answer: (B)

Think about where these tumors come from in the brain and spinal cord. Ependymal cells line the ventricles and the central canal of the spinal cord, forming the ependymal lining. Ependymomas arise from these lining cells, so their origin is tied to the ependymal layer that interacts with the CSF-filled ventricular system. This location helps explain why they can cause hydrocephalus by obstructing CSF flow, and histologically they often show features like perivascular pseudorosettes, indicating ependymal differentiation.

Schwann cells are the myelin makers of the peripheral nervous system, so tumors from them (schwannomas) arise outside the CNS. Oligodendrocytes produce CNS myelin, leading to oligodendrogliomas, and astrocytes produce astrocytomas and glioblastomas. Thus the origin from ependymal cells best fits the question.