Presentation
Tremors and papilledema of subacute onset.
Patient Data
MRI scan showing a non-restrictive, non-enhancing, thalamic space-occupying lesion with almost CSF-like intensity on T1 and T2-weighted images and partial attenuation on FLAIR images. There is no significant enhancement after contrast injection but vessels are seen within the lesion.
Major mass effects caused by the mass and acute hydrocephalus with transependymal edema are seen.
The patient went on to have surgery, with a ventricular shunt being placed and a biopsy taken from the lesion.
Histology showed low-celular-density neoplastic proliferation of middle-sized, rounded-nucleated cells with piloid processes. Immunohistochemistry showed mild GFAP-positive staining and a low mitotic index. Screening for the IDH-1R132H mutation turned out negative.
The pathology report labeled the case as low-grade glioma with characteristics in keeping with pilocytic astrocytoma.
Case Discussion
This is a case of a supratentorial pilocytic astrocytoma, which is relatively uncommon compared to its most frequent site of presentation: posterior fossa. This case highlights the importance of keeping in mind this supratentorial location, as pilocytic astrocytoma is a fairly common neoplasm in pediatric population.