Aggressive behavioral outbursts as an atypical presentation of giant pediatric trigeminal schwannoma: illustrative case.

backgroundTrigeminal schwannomas are rare intracranial tumors that predominantly occur in adults and only exceptionally present in the pediatric population. Behavioral disturbances, particularly pathological laughter and impulsive dysregulation, are uncommon neurological manifestations and typically indicate disruption of supranuclear or brainstem networks by an underlying structural lesion. Their association with trigeminal schwannoma remains exceedingly rare and poorly characterized. OBSERVATIONS: A 13-year-old boy presented with progressive behavioral disturbances, including pathological laughter, impulsivity, and agitation, along with focal neurological deficits in the form of hemiparesis. Neuroimaging revealed a giant trigeminal schwannoma with extension into the cerebellopontine angle and adjacent compartments, exerting significant mass effect on the brainstem and surrounding neural structures. The patient underwent surgical intervention with the aim of maximal safe resection. Postoperatively, there was improvement in both neurological deficits and behavioral symptoms, supporting a structural basis for the observed neuropsychiatric manifestations. LESSONS: This case highlights an unusual presentation of trigeminal schwannoma in a pediatric patient, manifesting predominantly with behavioral dysregulation. It underscores the importance of considering structural intracranial lesions in children presenting with atypical behavioral symptoms. Recognition of such manifestations has important implications for early diagnosis, surgical planning, and prognostication, and further supports a network-based understanding of affective and behavioral control. https://thejns.org/doi/10.3171/CASE26618.