Did we move the cyst? The role of cerebrospinal fluid diversion in the migration of neurocysticercosis

Abstract Mobile intraventricular neurocysticercosis (IVNCC) is dangerous because a freely floating cyst can suddenly obstruct cerebrospinal fluid (CSF) pathways. Ventricular cyst migration is recognized, but long-distance movement across compartments is rarely documented and its drivers remain debated. A case of IVNCC initially located in the left lateral ventricle is reported. During revision, acute-phase CT from the outside hospital was obtained and reviewed with neuroradiological input. These images confirmed acute obstructive hydrocephalus and showed the cyst actively crossing the foramen of Monro towards the third ventricle during the acute hydrocephalus-CSF diversion interval. This sequence documented unstable ventricular anatomy during the critical peri-decompression period. A focused narrative case-based review was updated using PubMed/MEDLINE, Embase and Cochrane Library. Twenty-three reports yielded 29 unique published migration events with extractable individual data. Intervention-associated CSF perturbation was temporally related to 15/29 events (51.7%), positional mechanisms to 10/29 (34.5%), spontaneous migration to 3/29 (10.3%) and an indeterminate trigger to 1/29 (3.4%). Operative escape, non-visualization or an empty target was reported in 10/23 (43.5%) cases with operative detail. These proportions are descriptive and not procedural risk estimates. Mobile IVNCC should be regarded as a dynamic obstructive lesion. Urgent CSF diversion remains indicated in acute hydrocephalus, but interval imaging before definitive surgery is advisable whenever feasible.