This is an example of left temporal ganglioglioma. Gangliogliomas are slow growing CNS neoplasms comprising of a mixture of neoplastic glial cells (primarily astocytes) and neoplastic ganglion cells (differentiated nerve cells), an in variable proportions1-5.
Gangliogliomas account for 0.4 to 7-6% of paediatric CNS neoplasms and approximately 1-3% of those in adults2. These tumors can occur anywhere in the neural-axis but are much more common in the brain than in the spinal cord1,2. The temporal lobe is the most common location of gangliogliomas, followed by, in order of descending frequency), cerebellum, parieto-occipital lobe, frontal lobe, and spinal cord6. These tumors have also been reported inthe brainstem, thalamus, hypothalamus, third and fourth ventricles, trigone of the lateral ventricle, pineal region, intrasellar region, and optic nerve4.
The most common clinical presentation is seizures, in particular, complex partial seizures, most likely a result of the high frequency of the temporal lobe location of these neoplasms1.
Although neuroradiological findings are not specific for gangliogliomas, the ability to diagnose this type of tumor greatly improved with the advent of CT and MRI. Common imaging findings of ganglioglioma on CT include1-6:
- Calcification with an amorphous appearance
- Subtle bony changes such as thinning of the calvarium
- Isodensity, hypodensity, or a cystic appearance of the lesion
- Contrast-enhancement of the solid non-calcified component of the lesion
Reported imaging characteristics on MRI include1-6:
- Cystic appearance of the lesion
- Hypointense on T1-weighted images
- Hyperintense solid component on T2-weighted images, with variable signal in the cystic component
The principal form of treatment of ganglioglioma is surgical excision, with most lesions being amenable to complete resection1-6. Current literature suggests that radiation therapy is of minimal and/or questionable benefit, even in tumors which involve eloquent areas4. Most patients with preoperative seizures are seizure-free following total surgical resection1.
Case courtesy of Associate Professor Pramit Phal