Presentation
First seizure episode.
Patient Data
There is a nodular cortical-subcortical right frontal solid mass, well-circumscribed and showing high T2 signal with partial suppression on FLAIR, no contrast enhancement and no diffusion restriction. The remainder of the imaged brain appears unremarkable.
Ventricular system and cisternal spaces appear normal.
There is no shift of the midline structures.
Case Discussion
This case was histologically proven to be a protoplasmic astrocytoma, which was one of the variants of diffuse low-grade astrocytomas. The term diffuse infiltrating means there is no identifiable border between the tumor and the normal brain tissue even though the borders may appear well marginated on imaging.
This tumor tends to occur in young adults with a reported predilection to frontal and temporal lobe. On imaging, they typically present as a cortical mass with a very high signal on T2 that characteristically suppress on FLAIR sequence (represent the areas with abundant microcystic change).
Until recently, protoplasmic astrocytomas were classified as a subtype low-grade astrocytoma, however, in the latest (2016) update to WHO classification of CNS tumors, protoplasmic astrocytomas no longer exists as a distinct entity.