Gangliocytoma

Gangliocytomas are rare benign (WHO grade I) CNS tumours which differs fromdiffer from gangliogliomas by the absence of neoplastic glial cells. Both tumours are defined by the presence of displaced ganglion cells (large mature neurons that show cytological or architectural abnormalities). 

Terminology

It should not be confused with dysplastic cerebellar gangliocytoma, which is also known as Lhermitte-Duclos disease. 

Epidemiology

They account for 0.1-0.5% of all brain tumours and occur in children and young adults ².

Clinical presentation

Tumours in the cerebral cortex present most commonly with epilepsy ⁴. 

Pathology

The key feature is a lack of glial cells. The tumour is composed of abnormal mature ganglion cells. 

Markers

Lack immunoreactivity to glial fibrillary acidic protein (GFAP).

Associations

Frequently associated with a dysplastic and malformed brain to varying degrees.

Location

This tumour may arise anywhere within the neuroaxis ⁴. Occurs most frequently at the floor of the 3^rd ventricle followed by the temporal lobe, cerebellum, parieto-occipital region, frontal lobe, and spinal cord.

Radiographic features

CT

Typically appears hyperattenuating on non contrast imaging. 

Has little associated mass effect and minimal or no surrounding vasogenic oedema. Calcification and cyst formation can occur.

MRI 

• T1: solid components typically hypointense  
• T2: solid components are typically mildly hypointense ²; cystic areas are hyperintense; calcification if present can be hypointense
• T1 C+ (Gd): solid components enhance

Treatment and prognosis

They tend to grow slowly and do not undergo anaplastic change.

Differential diagnosis

• ganglioglioma
• cortical dysplasia
• dysembryoplastic neuroepithelial tumour (DNET)