CNSC-33. GROUP3 MEDULLOBLASTOMA WITH BONE MARROW AND ABDOMINAL CAVITY METASTASIS:A CASE REPORT

Abstract Medulloblastoma is an infratentorial primitive neuro-ectodermal tumour, which is commonly occurring in childhood. It often spreads through the cerebrospinal fluid pathways with a very low rate of systemic metastases. Extra-central nervous system metastases have a poor prognosis in medulloblastoma. Here, we reported a case of Group3 medulloblastoma with bone marrow and abdominal cavity metastasis. A 10-year-old girl complained of headache, dizziness, vomiting and nausea. Magnetic resonance imaging(MRI) of the brain showed a large mass in the fourth ventricle and obstructive hydrocephalus. The surgery was performed to remove the mass and ventriculoabdominnal shunt was performed for obstructive hydrocephalus. Histological verification was proven classic medulloblastoma and next-generation sequencing confirmed molecular group of Gruop3 with MYC amplication. Radiotherapy was subsequently performed one month after the surgery. During the radiotherapy, brain MRI showed metastasis on the surface of the brain, which confer a poor prognosis. After the radiotherapy According to the therapeutic schedule, She would accept chemotherapy one month after the radiotherapy. But She suffered severe bone marrow suppression manifested as anaemia and thrombocytopenia, which can not be improved by medication and blood transfusion. A bone marrow aspiration was subsequently performed, and bone marrow smear showed large numbers of tumor cells at high magnification and was lack of normal hematopoietic cells. The girl was deteriorating rapidly with jaundice, ascites, hepatosplenomegaly and pancreatitis after the bone marrow aspiration. We found a lot of tumor cells in the bleeding tendency ascites and finally confirmed bone marrow and abdominal cavity metastasis concurrently. Eventually, She died less than a month after the metastasis and the overall survival was only 6 months. This typical case demonstrated severe bone marrow suppression of unknown origin should caused alarm and be performed bone marrow aspiration as soon as possible. The prognosis of medulloblastoma with extra-central nervous system metastases is poor and people may die in months.