Ganglioglioma of the brainstem: report of three cases and review of the literature.

BACKGROUND: Brainstem gangliogliomas are rare low-grade tumors that usually have a long clinical history. However, they may cause sudden death. There are only 31 cases of brainstem ganglioglioma reported in the literature, and only one has been studied with magnetic resonance (MR). We present three new cases of brainstem ganglion cell tumor studied with computed tomography (CT) (3 cases) and MR (2 cases) and discuss the clinical presentation, diagnostic imaging and treatment of these tumors. CASE DESCRIPTION: Age at presentation ranged from 19 to 59 years old. Two patients were female and 1 male. Duration of symptoms before diagnosis ranged from 1 year to nearly 14 years. Presenting complaints included syncope spells, cranial nerve deficits, headache, and gait instability. Imaging studies revealed well-circumscribed lesions involving the brainstem; the lesion was cystic in one case and calcified in one. They were iso- or hyperdense on CT scan, isodense on T1-weighted and hyperdense on T2-weighted MRI and frequently showed contrast enhancement. All tumors were operated through a posterior fossa craniectomy. Using microsurgical techniques only partial resection could be achieved, as there was no sharp delineation from the surrounding tissue in any case. Two of our patients had increased neurological deficits after surgery. Radiotherapy was not given. Follow-up of tumoral remnants has not shown clear tumor growth after 1, 3.5, and 10 years.
CONCLUSIONS: Imaging characteristics of brainstem gangliogliomas do not seem to differ from those in other locations and are not specific. Radical surgery is rarely if ever possible, nor is it advisable because of the risk of functional deterioration. However, because of their benign histology, partial resection seems to carry a similar prognosis as tumors in other locations that are amenable to complete resection.