Infratentorial ganglioglioma mimicking pilocytic astrocytoma.

Majority of tumors arising in posterior fossa in children are pilocytic astrocytoma. However, a small subset of these have a neuronal component that may either be admixed throughout with the glial component or may be segregated to one or two regions within the glial element. Interestingly, the radiological features of this subgroup are also distinctive, showing midline location, frequent cyst formation, hemorrhage, and circumscribed nature. Taken together, both radiological and pathological features can fairly predict the subgroup categorization within infratentorial gangliogliomas (GG), as has been recently elucidated. Moreover, these are characterized by distinct molecular abnormalities that are therapeutically targetable, making their recognition critical. We describe an example of infratentorial tumor with its radiology and morphological features distinct enough to place it under the category of GG, group II or pilocytic astrocytoma with gangliocytic differentiation.
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