Repair capacity of extraparenchymal cysts: radiological and evidence.

Extraparenchymal neurocysticercosis (EP-NC) responds poorly to anthelmintic treatment. Several factors are involved in this low responsiveness, including the host's heterogeneous immune response and the ability of the parasite to evade it. In this study, we present radiological and findings that demonstrate that cysts have the capacity to repair from injuries. Six patients (three with cases of subarachnoid, two with cases of intraventricular, and one with a case of mixed subarachnoid and intraventricular cysts) presented with neurological complaints and underwent either medical or surgical treatment. Follow-up magnetic resonance imaging (MRI) showed apparent resolution of the cysts. However, months later (10-56) new MRI scans revealed cysts at the same sites observed before treatment. Cysts surgically removed were maintained in RPMI-1640 medium supplemented with 10% fetal bovine serum. Monthly assessments demonstrated the growth of the parasites and the release of HP-10. Our findings demonstrate the ability of extraparenchymal cysts to grow and repair themselves. This capacity is likely another factor involved in the disease's poor treatment response.