Imaging of Hemispheric Brain Gangliogliomas

Abstract

The group of gangliogliomas (GGI) and ganglioneuromas (GGN) includes tumours composed of nerve cells and glial cells, usually astrocytes. In this sense, they differ from most primary CNS tumours in which only the glial cells show malignant change.

The differentiation between GGIs and GGNs is histological: if glial cells predominate, the lesion is called a “ganglioglioma”, when neuronal elements predominate, the term “ganglioneuroma” is used. Nevertheless, these two tumors types should be considered a single entity. Patients of all ages are affected, but the majority of tumours arise in the first two decades of life. The temporal lobe is a favorite site. The clinical history of these slow-growing neoplasms is usually one of long-standing focal epilepsy. The neuroradiological aspects of 13 hemispheric GGIs are described. Calcifications were seen in 5 case. All cases were histologically verified.

Three characteristic neuroradiological features were noted:

1) mainly cystic with a solid portion in 6 cases;

2) entirely cystic or with a mural nodule at the wall of the cyst in 3 cases;

3) entirely solid in 4 cases.

The neuroradiological diagnosis of GGI is important because radical surgical removal of these lesions is considered the first-line procedure. Surgery is justified by the good prognosis for patients in terms both of survival and quality of residual life, since it is curative or allows pharmacological control of epilepsy even after subtotal removal.