During the last 4 years (1993–1997) 6 patients (4 men and 2 women) with a third ventricle cyst were treated by stereotactic aspiration in the Hospital Na Homolce. The average age was 30.5 years (14–56). Because of their obstructive hydrocephalus two patients had undergone a V-P shunt and Torkildsen drainage prior to the stereotactic aspiration. After the stereotactic aspiration one patient’s cyst disappeared completely, two patients had evidence of a small 13 % and 15 % residue consisting of a remaining cyst wall and a small volume of a colloid material. The other patients’ cysts decreased to 21 %, 47 % and 63 % of their original volume. In all patients the foraminal Monrois’ obstruction was relieved. Five patients lost their clinical symptoms. Only in the case of one patient the seizures she suffered from before the operation reappeared also after the treatment. The results show, that stereotactic aspiration is a useful initial minimally invasive therapy for colloid cysts treatment.

        Key words: colloid cyst, stereotaxis, third ventricle