A series of 30 documented cases of intracranial hydatid cyst out of 33 pediatric and 45 total patients admitted to the Department of Neurosurgery of the School of Medicine at Istanbul University within the years 1952-1996 is presented. The pediatric population consisted of 73% of the series. Twenty patients (66%) are alive and well after a follow-up period of 8-45 years (mean 21.5 years). Six patients (20%) died and 4 (13%) were lost to follow-up. There were 3 early postoperative deaths (10%), 2 being in the pre-CT era. In 4 cases (13%), brain involvement was secondary, and 2 cases (7%) had multiple intracranial hydatid cysts. Age ranged from 4 to 16 years, with a mean of 10.4. There were 5 intraventricular (17%) and 2 (7%) intracranial extradural settlements. No children with posterior fossa hydatid cyst, primary skull hydatidosis or concomitant spinal involvement were detected. One patient (3%) presented with 'rhinorrhea' which in fact was a hydatid fluid leak. Preoperative pseudocerebellar syndrome, convulsion and extrapyramidal signs were seen in 6 patients each (20%). Five patients (17%) had permanent visual deficits, 3 being in pre-CT era. Out of 29 patients operated on, hydatid birth with intact cyst removal was achieved in 18 cases (62%), with no other manipulation needed. This rate has increased to 70% in the CT era. Intraoperative accidental rupture occurred in 8 cases (28%), of which 7 were localized frontally or had a frontal involvement (88% of the ruptured cases). Of the patients with intraoperative rupture, 5 are dead (63%) and they were all primary. In contrast, all 3 cases alive with intraoperative rupture are secondary. Three cases were punctured on purpose (10%). Four of the operated patients (14%) required long-term antiepileptic therapy, 3 having no preoperative seizures. Only 1 patient required a shunt (3%). Four cases had recurrence, all with intraoperative cyst rupture (14%). The long-term evaluation of the results yielded an overall mortality rate of 21%. Routine use of CT after the 80s decreased the rate to 14%. With the analysis of 50 years of data, it is strongly concluded that brain involvement in pediatric hydatid disease is a primary process if delayed diagnosis and insufficient treatment of extraneural hydatidosis are prevented. Copyright (C) 2001 S. Karger AG, Basel.