Corpus callosum agenesis and interhemispheric cysts: Epileptic evaluation and long-term outcome in 9 children

Abstract

Objective: To describe perinatal history, clinical phenotype, MR features, neurological outcome, and EEG patterns of pediatric patients with Corpus Callosum Agenesis (CCAg) and Interhemispheric Cysts. Methods: We selected 9 patients (8 males, mean age 7,3 +/−5,7) with CCAg (partial or complete) and interemipheric cysts from our imaging database of 378 patients with midline brain anomalies scanned at Gaslini Children Hospital from Jan 2005 to Jan 2017. Interemispheric cysts were grouped according to the 2001 Barkovich classification. Presence and location of gray matter anomalies such as polymichrogyria (PMG) or nodular heterotopia (NH) were recorded. Perinatal, clinical, genetic testing (when available), EEG pattern, age of onset of seizure (if present) with drug responsivity were reported. Results: Complete CCAg was present in 6 individuals, while the remaining cases had partial CCAg. Type1 cysts were present in 1 patient (subtype1a). Type 2 cysts were 8 (2 subtype2a, 2 subtype2b, 1 subtype2c and 1 subtype2d). Of interest, 2 patients had an MRI pattern overlapping between subtype2b and 2c (transmanterllar NH, diffuse PMG, macrocephaly, developmental delay). EEG epileptic activity was present in all but epilepsy onset was observed in 3/9 cases, with drug response in all. Major neurological defects were excluded. Developmental delay was observed in all cases but cognitive outcome, registered for 6/9 patients, was milder: 3/6 normal IQ, 2/6 bordeline and 1 with mild Intellectual Disability. Psychiatric data were recorded for 7/9 patients: hyperactivity and anxiety were frequent comorbidities (5/7). Conclusions: CCAg associated with Intehemispheric Cysts may be associated with a good neurological outcome with borderline or normal cognition and no major neurological signs in the majority of patients. Despite the presence of EEG anomalies, the occurrence of epilepsy in these cases is rare and usually responsive to antiepileptic drugs.