This is a differential diagnosis case of a temporal lobe cystic lesion in a young adult. There are a few relevant entities one must consider when encountering a lesion of this appearance in this age group:

• gangliocytoma: fully differentiated neural tumors, 60% occurring below the age of 20 years¹, can demonstrate solid and cystic components as well as fine, speckled calcification.

• ganglioglioma: although primarily occurs in a pediatric population, the incidence in young adults is higher than that of ganglioneuroma

• pilocytic astrocytoma: occurring mostly in pediatric age group, 60% are found in the cerebellum with optic nerve, hypothalamus and brain stem consisting most of the other 40%. The location of the lesion, in this case, is somewhat unusual for a pilocytic astrocytoma

• DNET: mostly occurring in temporal lobes of young people, this is a relevant consideration, in this case

• cystic metastasis: cystic metastasis with a mural nodule is the last but not least differential for this lesion

The patient went on to have surgery. 

Histology

Final diagnosis: ganglioglioma (WHO grade 3) with high-grade glial component resembling glioblastoma.