Ganglioglioma

Gangliogliomas are the most common mixed glioneural tumors of the CNS and most commonly present with seizures. About 40% occur in the temporal lobe, followed by the parietal (30%) and frontal (20%) lobes. They can also be found in the anterior third ventricle, cerebellum, spinal cord, and optic nerves.

Imaging

On CT, they may be hypo (40%) mixed cystic and nodular (30%), isodense (15%), or hyperdense (15%). Mass effect is variable, and there is generally no edema. Up to 50% have calcifications and about 50% demonstrate faint enhancement.

They are hypo- to isointense on T1-weighted images. Solid enhancing components are usually seen (A and B). Calcifications will be hyperintense to gray matter. The solid and cystic parts will be high signal on T2-weighted images (C). No significant peritumoral edema is seen (FLAIR, D).

Variants

The glial portion of a ganglioglioma defines its aggressiveness, and degeneration of the glial component may lead to an anaplastic ganglioglioma.

A desmoplastic infantile ganglioglioma (DIG) is a variant of ganglioglioma that is usually seen in the first 2 years of life. Like the regular ganglioglioma, it is a low-grade tumor with good prognosis. As opposed to the standard ganglioglioma, however, DIGs are more commonly seen in the frontal and parietal lobes. Imaging features may be identical to pilocytic astrocytomas: A large cyst with a peripheral (cortical) enhancing nodule. Some may also have a calcified rim.

References

Neuroradiology: The Requisites. Second ed. pp 136-138.