The Characteristics Of Pathological And Molecular Subtypes Of Medulloblastomas Primitive In Cerebellopontine Angle

Object: Medulloblastoma primitive in cerebellopontine angle is rare. Currently, only 36 cases were reported in the literatures. Compared with other common diseases in this region, no characteristic clinical presentations and imaging findings can distinguish preoperatively, which makes preoperative diagnosis difficult. Furthermore, diverse origins of the tumors and unclear understanding about the molecular biological characteristics also make the prognosis of the disease difficult to identify. This study was designed to find a way to help determine the prognosis of the disease through the pathology and molecular subtypes of CPA medulloblastoma.Methods: A retrospective study of the clinical data of 11 patients with CPA medulloblastoma was performed, so did the follow-up. 10 tumor samples of these patients were stained by the HE to identify the pathological type and by immunohistochemistry to determine the molecular subtype. Combined with these data, the Chi-square test and Kaplan-Meier statics were performed.Results: Of the 10 samples that we can get, there are 6 cases of CMBs, 3 cases of DNs, 1 case of LC/A; 8 cases of SHH type, and 1 case of WNT type and Non-SHH/WNT type respectively. Different age groups(p=0.007, <0.05), pathological types(p=0.01, <0.05) and molecular subtypes(p=0.007, <0.05) differ significantly in the prognosis.Conclusions: The CPA medulloblastomas are rare to see in clinic, so the preoperative diagnosis is always difficult. The rate of gross total resection is low for CPA MB, but it does not show significant difference in the survival analysis for patients with total and subtotal resction. The distribution of pathological types does not differ with the MB in the common sites. However, the ratio of SHH subtype is high for CPA MB, which demonstrates that the overall prognosis of medulloblastoma in this site is better.The identification of the pathological type and molecular subtypes benefit a lot to determine the prognosis of the disease.