Subependymoma - atypical appearance

Case contributed by Angel Donato
Diagnosis certain


Six-month history of headache, dizziness, and loss of balance.

Patient Data

Age: 40 years
Gender: Male

The MRI with gadolinium shows a cystic mass with mural nodules with heterogeneous enhancement of the solid area with compressive effect on the fourth ventricle.
No diffusion imaging abnormalities were revealed.


Clusters of isomorphic nuclei embedded in a dense, fine, glial fibrillary background, occasional calcification, no necrosis or hemorrhage. GFAP positive, P53 negative, Ki 67 proliferation index <  1%. 

Final diagnosis: Subependymoma WHO grade I

Cortesy Fernando Velandia Hurtado MD.

Case Discussion

This is an unusual case in that the appearance of this tumor is quite atypical for a subependymoma. 
Subependymomas are slow-growing and uncommon neoplasms representing 0, 51% of all CNS tumors that arise within the ventricular system, and the spinal cord and are frequently found in the lateral wall of the fourth ventricular in about 50 to 60%.

Subependymomas, previously known as subependymal astrocytomas, are low-grade noninvasive gliomas corresponding to WHO grade I with favorable prognosis and the origin is unknown. Still, some findings suggest that it may arrive from multipotent glial progenitors in the subventricular zone.
Histopathologic are formed by clusters of isomorphic nuclei embedded in a dense, fine glial fibrillary background, occasional calcification. No necrosis or hemorrhage, also GFAP positive, KI 67 proliferation index <  1, and P53 negative.
DNA methylation divided subependymomas into three molecular subgroups: supratentorial(ST), posterior fossa(PF), and spinal (SP).

On MRI, the subependymomas usually are a well-defined solid or mixed solid and cystic intraventricular mass. The solid component is hypointense or isointense in T1WI and hyperintense in T2WI and FLAIR. They usually have focal or minimal enhancement. Hydrocephalus is very common until 94%. Hemorrhage or calcification may also be present. Cystic degeneration is seen in 80% of the patients.

Differential diagnoses include other intraventricular neoplasms such as central neurocytomas, choroid plexus papilloma, meningiomas, low-grade astrocytoma, ependymomas, medulloblastomas and others like hemangioblastoma or pilocytic astrocytoma. 

The treatment included surveillance, gross total surgical resection, subtotal resection with or without radiotherapy with no significant role for radiation concerning overall survival in the SEER analysis. Immunotherapeutic treatment is potentially beneficial as an adjunct to surgery or who are not surgical candidates. There is no benefit from chemotherapy.

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