成人不典型表现髓母细胞瘤1例及文献复习

Atypical medulloblastoma in adult: a case report with literature review

目的探讨成人不典型髓母细胞瘤的MRI表现,提高对髓母细胞瘤的认识。方法回顾性分析1例经手术病理证实的成人髓母细胞瘤病人MRI资料并行文献复习。结果 1例不典型成人髓母细胞瘤的影像表现:CT上双侧小脑半球、小脑蚓部呈弥漫高密度,边界不清;MRI表现为双侧小脑半球、小脑蚓部及左侧桥臂呈弥漫性稍长T1、稍长T2信号,DWI上呈稍高信号,ADC图上呈稍低信号,增强扫描病变大部分未强化,局部呈脑回样强化。1H-MRS检查可见桥臂区病变Cho峰升高,NAA峰减低,Cho/NAA明显升高。PET显像中病变呈18F-FDG低代谢,11C-MET高代谢。结论成人髓母细胞瘤的影像表现不典型,多种影像检查对诊断本病有重要价值,确诊需依赖病理组织学检查。

Objective To evaluate the MRI findings of medulloblastoma in an adult, and to enhance the knowledge of this tumor by reviewing literatures. Methods One rare adult case of medulloblastoma in eerebellar hemisphere proved by pathology was analyzed, and literatures were reviewed. Results The radiologieal findings： the CT images showed a nearly homogeneous hyperattenuated lesion in bilateral hemisphere and vermis; and the MRI features： the mass presented slightly hypointensity on TIWI and slightly hyperintensity on T2WI, and DWI, slightly hypointensity on ADC in bilateral eerebellar hemisphere, vermis and left bridge arm. After contrast administration, the major part of the lesion showed no significant enhancement, local lesion demonstrated a gyri-form enhancement. Spectral map showed high choline, low NAA peak, and a significantly high Cho/NAA ratio at the bridge arm. The lesion showed 18^F-FDG hypometabolism and 11^C-MET hypermetabolism. Conclusion The radiologieal characteristics of adult medulloblastoma are atypical, radiological methods could provide important information in diagnosis of this disease. The final diagnosis relies on pathological examination.