Langerhans cell histiocytosis (LCH) can involve the central nervous system and produce cerebellar and brainstem lesions. This report describes six patients with multisystem LCH who developed neurological and psychiatric disturbances in association with cerebellar abnormalities on magnetic resonance imaging. The authors emphasize neuropsychiatric symptoms that have received limited attention in prior reports, particularly impulsivity, compulsivity, and social inappropriateness.
Across the six cases, patients manifested a combination of motor, cognitive, and behavioral disturbances. Ataxia and cognitive impairment were present alongside a range of behavioral problems. The series documents that severity and pattern of behavioral symptoms varied with the extent of cerebellar and brainstem involvement: patients with more extensive lesions exhibited more pronounced impulsive and compulsive behaviors and socially inappropriate actions, whereas more restricted dentate abnormalities were associated with milder attentional deficits and impulsivity.
Behavioral disturbances observed included hyperactivity, poor impulse control, hypersexuality, pathological gambling, substance abuse, aggression, and socially inappropriate behavior. These features were highlighted as underrecognized components of the neuropsychiatric phenotype in cerebellar LCH.
Magnetic resonance imaging identified cerebellar and brainstem abnormalities in all reported patients. When serial imaging was available, the authors reviewed temporal relationships between lesion evolution and symptom severity. The degree of cerebellar and brainstem involvement broadly corresponded to behavioral severity across the cases, suggesting a clinico-radiological association between lesion burden and neuropsychiatric manifestations.
This series expands the recognized behavioral manifestations of cerebellar LCH by drawing explicit attention to impulsive-compulsive symptoms and disinhibited social behavior. The authors argue these behaviors likely form part of the neuropsychiatric spectrum of cerebellar LCH and should be systematically sought during clinical assessment. The listed manifestations indicate involvement beyond traditionally emphasized motor and cognitive deficits.
A notable element of the series is one patient for whom neuroimaging was obtained during a psychiatric exacerbation and again shortly afterward. In this case, psychiatric worsening paralleled progression of cerebellar lesions on MRI. Following immunomodulatory treatment, the patient showed both clinical and radiological improvement. The authors present this single longitudinal observation as supportive, though not definitive, evidence linking cerebellar lesion dynamics to psychiatric symptom fluctuations in LCH.
In addition to the case series, the authors conducted a systematic literature review to identify previously reported neuropsychiatric manifestations associated with cerebellar LCH. Although the abstract does not detail individual prior reports, the review is described as extending the phenotype and highlighting that impulsivity, compulsivity, and social inappropriateness are underreported features in existing literature.
The authors discuss the potential contribution of cerebellar networks, particularly cerebello-limbic circuitry, to the observed behaviors. They propose that disruption of these circuits by LCH-related cerebellar and brainstem lesions may underlie impulsive, compulsive, and disinhibited social behaviors. This interpretation aligns with growing recognition of nonmotor cerebellar functions and the cerebellum’s connectivity with limbic and prefrontal systems involved in emotion and impulse control.
Based on the case series and literature review, the authors recommend systematic behavioral assessment and longitudinal follow-up for patients with cerebellar involvement in LCH. They highlight the need for further studies to clarify mechanisms and to evaluate targeted therapeutic approaches for neuropsychiatric manifestations. The single documented case of clinical and radiological improvement after immunomodulatory therapy suggests potential reversibility in some patients, but the authors note that broader evidence is needed.
Overall, these cases add to the clinical spectrum of cerebellar LCH by underscoring impulsivity, compulsivity, and social inappropriateness as clinically relevant, underrecognized neuropsychiatric features. The report calls for increased clinical awareness, systematic monitoring, and research into targeted interventions and the role of cerebellar networks in these behaviors.