Paediatric Radiology

Case 3 :
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A 6 year old female, operated elsewhere for a posterior fossa tumour, presented with headache and vomiting of 15 days duration. A CT scan head was performed.
What is the diagnosis ?


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Answer : Study shows a hyperdense, enhancing, partly cystic, midline posterior fossa mass lesion extending toward the left cerebello pontine angle.

Diagnosis :

Ependymoma Ependymoma is the third most common intra cranial neoplasm in children, the peak incidence is in children less than 5 years of age (50%), with a much smaller second peak in adults.
The location is mostly infra tentorial, with 70% from the fourth ventricle, and they often extend into the cerebello-pontine region or vallecula.
Most of these tumours are slow growing, and malignancy is rare, however, inspite of a low mitotic index, most of these tumours recur and have relatively poor outcome (25-50% 5 year survival rate).

Imaging findings :

CT shows a mostly isodense, calcified, partially cystic, midline posterior fossa mass lesion with variable enhancement. Extension is often seen laterally into the cerebellopontine angle or posteriorly into vallecula. Supratentorial ependymomas are often peri ventricular or parenchymal, not intraventricular, and they are less often calcified; these tumours are indistinguishable from astrocytomas.
MR shows a typical solid fourth ventricular mass, non specific heterogenous signal with propensity to spread via foramen of Magendie, Luschka with a characteristic "plastic" configuration.

References :
Spoto GP, Press GA, Hesselink JR, Solomon M. Intracranial ependymomas and subependymoma : MR manifestations. AJNR 1990; 11: 83-91.
Ann Osborn (Intracranial Neoplasms) from NICER series on Diagnostic Imaging. Eds. Derek Hashwood-Nash, Holger Pettersson. Pgs. 34-55.