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Medulloblastoma occurs in 0.5 per 100,000 children younger than 15 years annually. It is a tumor that primarily arises in the posterior fossa, however a substantial minority of patients would present in other parts of the central nervous system. A study by Park, et al (1983) showed that supratentorial metastases were present only in 14.6% of cases and spinal cord metastases were seen in 12.5% upon diagnosis. In a SEER update by McNeil, et al (2002), in 768 patients with medulloblastoma, only 7% presented with a supratentorial anatomic location, while only 3% presented with a mix of both supratentorial and infratentorial location.
This is a case of an eight-year-old male who initially presented with a 3-week history of headache and vomiting, but later progressed to symptoms of ataxia and Cranial Nerve 6 palsy. Further work-up was done revealing multiple cranial lesions. The patient underwent suboccipital craniectomy, partial excision with biopsy of the 4th ventricular tumor and ventriculostomy of the right parietal area. Histopathology confirmed a diagnosis of medulloblastoma. Further work-up revealed that aside from the unusual multiple supratentorial metastases upon presentation, the patient also presented with spinal drop metastases thus was staged as high-risk. A multidisciplinary team meeting was initiated to determine the appropriate treatment plan for the patient. The management was primarily based on the Pediatric Oncology Group 9031 protocol but modified due to the extent of disease. The patient received concurrent craniospinal radiotherapy and first phase of chemotherapy (Cisplatin + Etoposide for 3 cycles), and went on to complete the second phase of chemotherapy (Vincristine + Cyclophosphamide for 7 cycles). One year after initiating treatment, follow-up revealed a good response with further decrease in the extent of the ill-defined non-enhancing signal abnormalities seen in the pre-treatment MRI and noted no new abnormalities in the supratentorial and infratentorial cranial region. The spinal MRI however showed a significantly decreased residual compared to pre-treatment MRI, but also no new abnormalities were noted.