Abstract
BACKGROUND: Psychiatric symptoms, including psychotic manifestations such as hallucinations and delusions, are common in patients with brain tumors, typically associated with tumors in the frontal and temporal lobes. Psychotic symptoms are rarely linked to cerebellar tumors. However, recent evidence suggests that the cerebellum is involved in higher-order functions like cognition, emotional regulation, and social behavior. This report describes the case of a patient with autism spectrum disorder (ASD) who presented with a unique combination of a cerebellar tumor and psychotic symptoms, achieved complete remission of psychotic symptoms without antipsychotic treatment, and was followed up for three years. CASE PRESENTATION: A 16-year-old male with longstanding ASD presented with auditory hallucinations, delusional beliefs, and thought disorder. Since childhood, he displayed features such as poor eye contact, hypersensitivity to sounds, solitary play, restricted interests, and behavioral rigidity. At age 13, he began experiencing fluctuating psychotic symptoms, which were later diagnosed as schizophrenia-like psychotic features alongside his ASD. Brain magnetic resonance imaging (MRI) revealed a 3-cm cerebellar mass, which was identified as a pilocytic astrocytoma upon surgical resection. Notably, the patient's psychotic symptoms completely resolved after surgery, without the use of antipsychotic medication, and have not recurred during a 3-year follow-up, while his core characteristics of ASD remained unchanged. CONCLUSIONS: This case suggests that cerebellar pathology may contribute to the development of psychotic symptoms, supporting the hypothesis that cerebellar dysfunction can lead to schizophrenia-like features. It also highlights the potential link between cerebellar dysfunction and ASD. Given the slow-growing nature of pilocytic astrocytomas, the case highlights the importance of considering cerebellar pathology in the differential diagnosis of psychosis, with implications for understanding disorders like ASD.