Pilocytic astrocytoma with leptomeningeal dissemination is a rare phenomenon and can be associated with obstructive hydrocephalus and an unfavorable prognosis. Herein, we report a seventeen-year-old boy with a history of ventriculo-peritoneal shunt insertion due to severe hydrocephalus who presented with progressive headache and vomiting together with ocular and cerebellar signs and symptoms. Neuroimaging confirmed the presence of multiple intracranial masses in the cerebellum and thalamus. Intracranial dissemination of tumor to the the leptomeninges was seen during neuroendoscopy. Simultaneous biopsy and endoscopic third ventriculostomy were performed and the diagnosis of low-grade pilocytic astrocytoma with leptomeningeal dissemination was made by histological examination. The patient underwent chemotherapy in combination with radiotherapy to reduce the risk of reoccurrence of the primary tumor and was followed for one year.