Cerebral gangliogliomas: clinical characteristics, CT and MRI.

Eight patients with ganglioglioma who received surgical treatment at our institute between January 1989 and January 1997 were reviewed to determine their clinical, CT and MRI characteristics. Tumours were located in the temporal lobe (four patients), trigone of the lateral ventricle (two patients), basal ganglia (one patient) and fronto-temporal lobe (one patient). On imaging, two types of tumours were seen, a solid mass in 5 patients (62.5%) and a cystic mass in three patients (37.5%). Six complete tumours (75%) and all of the solid components of the cystic tumours were enhanced by contrast medium. Seven tumours (88%) had no peripheral oedema. On CT, the tumours being studied appeared as iso-(62.5%) or low density (37.5%) intra-axial tumours. Four tumours (50%) contained calcification. On MRI, the tumours appeared as well-circumscribed, iso-(62.5%) or low intensity (37.5%) intra-axial tumours on T1 weighted images, and as high (75%) on T2 weighted images. Three underwent total resection, 2 subtotal resection and 3 partial resection. No patients had have any further treatment such as radiation therapy or chemotherapy. Postoperative studies were conducted on all patients with an average follow-up period 56 months (range 4-147 months) after surgery. There was no evidence of recurrence of tumours or of growth of residual tumours. We observed gangliogliomas which were located in unusual regions such as the trigone in two of the patients. To our knowledge, our series is the first report to describe trigonal gangliogliomas. We conclude, therefore, that ganglioglioma should be included as a possibility in the differential diagnosis of intracranial masses, even when they are located in the trigone.