Background: Desmoplastic nodular medulloblastoma (DNMB) is an uncommon but malignant variant of medulloblastoma that typically occurs in children. Although it is malignant in nature, children with DNMB have a high 5-year overall survival rate. Here, we present a complex case of a DNMB in a 6-year-old pediatric patient. This study highlights the importance of early and effective treatment approaches in DNMB through a challenging pediatric case.Case Presentation: A 6-year-old boy with a genetic condition of delayed motor and mental development and ischemic-hypoxic brain damage was brought to our center. He was observed to have drowsiness, whims, and seizures. An initial non-contrast-enhanced head computed tomography (CT) scan revealed occlusive hydrocephalus. Subsequently, a contrast-enhanced brain magnetic resonance imaging (MRI) showed a lesion at the posterior fossa, growing towards the corpora quadrigemina, with areas of growth towards the right cerebellar hemisphere and vermis. After a subtotal resection was achieved in the initial surgical intervention, a second surgical procedure was performed, during which the residual lesion was grossly totally resected. The patient’s treatment process was complicated by hydrocephalus, which was initially managed with Ommaya reservoir implantation, followed by ventriculoperitoneal shunt placement. The patient then received radiotherapy and adjuvant chemotherapy with cyclophosphamide, vincristine, carboplatin, and intravenous methotrexate. Conclusions: Despite its malignant nature, early diagnosis and appropriate treatment strategies, including gross total resection followed by chemoradiotherapy, significantly improve overall survival rates. Managing complex cases requires timely intervention and close postoperative monitoring, particularly in cases with fourth ventricle involvement, where hydrocephalus management is critical.