Posterior fossa ependymoma

Case contributed by Assoc Prof Frank Gaillard


Incidentally found on investigation of radiculopathy

Patient Data

Age: 40 years
Gender: Male

An ill-defined mass posterior to the medulla is vaguely seen, with a single flec of calcium. 


There is a mass arising from the foramen of Magendie and extending into the cisterna magna and through the foramen magnum posterior to the medulla. This is isointense to brain parenchyma on T1-weighted sequence, heterogenous but predominantly hyperintense on T2, and enhances heterogeneously post contrast administration. Numerous tubular T2 flow voids surround this mass. It does not exhibit increased diffusion restriction. Some areas of susceptibility artefact in the superior aspect of the mass. There is no invasion of the adjacent brain parenchyma. The mass does not extend into the fourth ventricle. No evidence of hydrocephalus. No periventricular high signal. Brain parenchyma is otherwise unremarkable.


Enhancing posterior fossa mass as described above. Most likely diagnosis is that of an ependymoma. Absense of large flow voids, soft appearance and only intermediate enhancement make hemangioblastomas and choroid plexus papillomas less likely differential diagnosis.

DSA (angiography)

Via a right groin approach ( 5-French sheath ) bilateral common carotid (not shown), external carotid (not shown) and vertebral angiography was performed. No abnormalities have been detected. In particular there is no obvious enhancing mass at the level of the foramen Magnum.

Case Discussion

The patient went on to have a resection confirming the diagnosis of an ependymoma. 


Paraffin sections show a moderately hypercellular tumor. Tumor cells have uniform round and oval nuclei with an open finely granular chromatin pattern and a variable amount of clear and finely granular eosinophilic cytoplasm. These are arranged predominantly in diffuse sheets. Moderately well-formed perivascular pseudo-rosettes are noted and there are cystic and tubular spaces lined by ciliated cells with similar nuclear features to cells within the solid areas. No mitotic figures, vascular or endothelial cell hyperplasia or necrosis are seen. Areas of hyalinisation are noted. Eosinophilic, PAS+ secretory like bodies are seen in the cytoplasm of many tumor cells.


  • GFAP positive
  • EMA positive peri-nuclear dot pattern in small number of tumor cells
  • PgR negative
  • CEA negative
  • Topoisomerase labeling index: Approximately 1%

​FINAL DIAGNOSIS: posterior fossa ependymoma (WHO Grade 2).

Note: as molecular profiling was not carried out in this case, it would have the diagnosis of posterior fossa ependymoma not otherwise specified (NOS). 

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