MRI features of medulloblastomas in adults and misdiagnosis analysis

TAN Zhong-lun; CHENG Guan-xun; GUO Xiao-ting

Abstract：Objective To discuss the MRI features of Medulloblastomas in adults and to analyse the reason of misdiagno‐sis .Methods MRI imaging of 15 adults with medulloblastoma proved by pathology were retrospectively analysed .All ca‐ses were examined with conventional brainMRI and enhanced on T1 WI sequence ,3 cases with diffusion weight imaging (DWI) .Results 5 lesions were located at midline posterior fossa (3 in cerebellar hemispheres and 2 in the fourth ventri‐cle) ;8 lesions located at cerebellar hemisphere (3 lesions in left and 5 in right) ;2 lesions were located at cerebellopontine angle (CPA) .All the lesions showed heterogeneous hypointense or isointense on T1 WI ,hyperintense or isointense on T2 WI and FLAIR ,with cystic degeneration in the tumor .The solid ortion of the tumor gave slightly lower signals on ap‐parent diffusion coefficient map .The solid masses were enhanced at different extension .There were only 4 cases of preop‐erative correct diagnosis of medulloblastoma .But ,3 cases were misdiagnosed as ependymoma ,2 cases as hemangioblas‐toma ,2 cases as meningioma ,2 cases as schwannoma ,1 case as Glioblastoma ,and 1 case as lymphoma .Conclusion Medulloblastoma in adult is rare ,site of occurrence is variable ,and MRI features are lack of specificity ,which are the main reasons of misdiagnosis .