Neuroblastoma-associated Opsoclonous Myoclonous Ataxia Syndrome: Profile and Outcome Report on 15 Egyptian Patients.

Opsoclonous myoclonous ataxia syndrome (OMAS) is a rare primarily immune-mediated disease in children. The current study aim was to find out the patterns and outcome of OMAS associated with neuroblastoma (NBL) among Children's Cancer Hospital-Egypt patients. Data was reviewed for 15 eligible patients enrolled between 2007 and 2016. OMAS treatment included prednisolone and cyclophosphamide with/without intravenous immunoglobulin; NBL treatment was given according to risk-corresponding protocol. Patients' age ranged from 0.75 to 12 years at presentation with male/female: 1.1/1. Concurrent diagnosis of OMAS and NBL occurred in 6 patients (40%). OMAS preceded NBL within 0.25 to 2 years in 33%, while NBL preceded OMAS within 0.5 to 1.5 years in 27%. Full OMAS picture was present in 10/15 patients, while 20% presented with truncal ataxia and myoclonus, 1 with truncal ataxia and opsoclonus, and 1 had opsoclonus and myoclonus. Median time till improvement of manifestations was 5 months. The 5-year OMAS progression-free survival was 33.3%, where 10 patients needed second-line therapy due to relapse/progression of OMAS. The median time to progression was 28 months measured from OMAS diagnosis. All patients remained alive with NBL 5-year overall survival of 100% and event-free survival of 85.7% for. However, 73% of the patients showed late sequelae ranging from ocular to cognitive, behavioral and motor disorders; rarely seizures and hemolytic anemia.