|This article has been reviewed by the NeuroWiki Editorial Board|
Axial MRI of right temporal ganglioglioma
|Cell of origin||Glial precursor|
|Survival||Dependent on WHO grade|
Ganglioglioma is a well-differentiated, slowly growing biphasic neuroepithelial tumor composed of neoplastic mature ganglion cells and neoplastic glial cells. Ganglioglioma is considered a WHO Grade I or II tumor, though some lesions may be considered WHO Grade III or IV based on the degree of malignancy of the glial component.
Gangliogliomas represents less than 1% of all brain tumors. The peak incidence is in children and young adults between age 8.5 and 25 years, with a mean age of occurrence at 9.5 years. There is a slight female predominance (1.1:1).
Gangliogliomas may occur throughout the CNS, but are most commonly found in the temporal lobes.
Symptoms are site-specific, but are stereotypically long-standing. Ganglioglioma is the most common tumor associated with chronic temporal lobe epilepsy. Seizures are the most common presenting symptom.
MRI demonstrates a well-demarcated lesion with variable contrast enhancement. Scalloping of the calvarium may be seen adjacent to superficially located tumors. On non contrast CT, the lesions are hypodense with scattered hyperdensities from calcification.
Gangliogliomas are solid or cystic tumors that are well delineated from the surrounding normal brain. Calcifications may be present.
HistopathologyGangliogliomas are well-differentiated, slowly growing biphasic neuroepithelial tumors composed of neoplastic mature ganglion cells and neoplastic glial cells. Occassional mitoses may be present. Grading is based upon the degree of malignancy seen in the glial component of the tumor. Microscopically, the ganglion cells demonstrate nerve cell differentiation. They are synaptophysin positive.
A splice-site-specific polymorphism in the TSC2 gene on chromosome 16p13.3 may predispose to development of sporadic ganglioglioma.
Mean survival time depends on the malignant grade of the glial component of the tumor. WHO Grade I tumors are surgically curable. Higher-grade lesions behave similarly to their glial analogs.
- i. Ganglion cell neoplasms present in the first three decades with the first symptoms usually epilepsy; predilection for the temporal lobe causing complex partial seizures; often form a cyst with a mural nodule
- ii. Contain both disorganized ganglion cells with round nucleus, prominent nucleolus, and Nissl substance along with neoplastic glial cells which greatly outnumber the ganglion cells
- iii. Stain with both synaptophysin and GFAP with low Ki-67 labeling