Early Recurrence of an Adult Desmoplastic Medulloblastoma With Intramedullary Spinal and Suprasellar Metastases.

Medulloblastoma is a highly aggressive embryonal tumor of the central nervous system with a strong tendency for dissemination through cerebrospinal fluid. While it occurs predominantly in pediatric populations, it is uncommon in adults. Intramedullary spinal metastases and suprasellar involvement are exceptionally rare patterns of dissemination in adults. We report the case of a 21-year-old male diagnosed with desmoplastic medulloblastoma of the cerebellar vermis who underwent ventriculoperitoneal shunting, gross total resection, and craniospinal radiotherapy. Despite receiving standard multimodal therapy, the patient developed recurrence within 12 months, presenting with rapidly progressive paraplegia and bilateral blindness. Magnetic resonance imaging (MRI) revealed tumor recurrence in the posterior fossa, suprasellar metastases involving the optic chiasm, and extensive spinal dissemination, including intramedullary and intradural metastatic lesions. This case highlights the potential for early recurrence and extensive neuroaxis dissemination in adult medulloblastoma despite initially favorable histopathology and appropriate multimodal therapy. The coexistence of intramedullary spinal metastases and suprasellar involvement represents an exceptionally rare dissemination pattern in adults, underscoring the importance of maintaining a high index of suspicion during follow-up. The development of new neurological deficits during follow-up should prompt urgent imaging of the entire neuroaxis to evaluate for metastatic dissemination. Comprehensive neuraxis surveillance and molecular characterization remain critical components in the evaluation and management of adult medulloblastoma, as they provide essential information for prognostic assessment and therapeutic decision-making.