INTRODUCTION
Medulloblastoma (MB) is rarely seen in adulthood. Treatment guidelines are derived from studies of the pediatric population, results favoring the Packer regimen (cisplatin plus cyclophosphamide or lomustine plus vincristine). MB rarely has extraneural metastases, especially the bone marrow.
CASE PRESENTATION
A 32-year-old female with a past medical history of cerebellar MB confirmed on surgical pathology status post resection, weekly radiation and vincristine treatment presented to us in clinic to re-establish care. She was lost to follow-up 9 months after initial diagnosis and wished to continue treatment. She was started on Lomustine, Cisplatin and Vincristine after discussion with our colleagues at MSKCC, where she had received her initial treatment. After cycle three, she developed intractable bone pain and pancytopenia. Bone marrow biopsy revealed metastasis of Sonic Hedgehog Desmoplastic/nodular variant MB. PET and CT imaging confirmed metastatic disease in the bone marrow and repeat MRI brain showed abnormal nodular enhancement. CSF analysis to assess for spinal metastasis was negative. The patient was started on Temozolomide, Irinotecan and Bevacizumab with significant improvement in bone pain and radiological improvement noted on PET and CT scans. After cycle six, the patient had increased bone pain and repeat FDG-PET showed increased uptake, however, she continued to receive treatment and her pain has improved off narcotics.
DISCUSSION
We highlight a case of adult MB in the bone marrow responsive to temozolomide, irinotecan and bevacizumab. We conducted a literature search using PubMed, Medline and Web of Science between 1990 to 2022. In 2021, COG Phase 2 screening trial showed bevacizumab, temozolamide/irinotecan therapy significantly reduced the risk of death with recurrent MBs, two studies included patients up to 21 and 23 years of age. Other modalities showing some response include Vincristine plus cyclophosphamide as well as high dose carboplatin, thiotepa and etoposide alongside autologous SCT. Vismodegib has also shown varied response of 15 months in two adults with extraneural MB metastasis. Given the unique entity of adult MB and extraneural metastasis, limitations include small sample and lack of generalizability.
CONCLUSIONS
Extraneural metastasis of MB yields a poor prognosis. Future considerations include randomized trials to establish efficacy of Temozolomide, Irinotecan plus Bevacizumab in this population.
