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Posterior fossa pilocytic astrocytoma

Case contributed by Maxime St-Amant
Diagnosis certain

Presentation

Cerebellar symptoms.

Patient Data

Age: 5 years
Gender: Male

Posterior fossa mass containing cystic foci either originating from the fourth ventricles or invading it secondarily, responsible for obstructive hydrocephalus with transependymal resorption. ADC (not shown) demonstrates only moderate restricted diffusion. 

The differential diagnosis for this lesion includes medulloblastoma and pilocytic astrocytoma. A rarer tumor, atypical teratoid rhabdoid tumor (AT/RT) can also have this appearance, as could an ependymoma, although there is obvious intraparenchymal extension into the right cerebellar peduncle. 

Case Discussion

The pathologic diagnosis for this tumor was confirmed to be that of pilocytic astrocytoma

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