Colloid cyst of the third ventricle-a benign tumor with a 'malignant' nature: a report of two cases

ABSTRACT

Colloid cysts of the third ventricle are rare benign intracranial tumors accounting for less than 1.5% of brain tumors. Two cases, both of young patients presenting with sudden neurological deterioration after a long period during which they complained of intermittent headache and personality changes, are presented in this report. In the first patient the initial working diagnosis made at the district hospital referring the patient was a central nervous system infection and a lumbar puncture was contemplated but not performed. In both patients, urgent brain imaging showed acute obstructive hydrocephalus due to a mass in the area of the third ventricle which later histologically proved to be a colloid cyst. The radiological appearances of the tumor and its consequences were rather unusual in that the third ventricle was also dilated in both cases in addition to the lateral ventricles. A brief discussion of these tumors is presented with emphasis on modes of presentation and radiological appearances