側頭部腫瘍と鑑別が困難であった急性再発性散在性脳脊髄炎の1例

ARDEM Mimicking a Temporal Lobe Tumor

I．はじめに

　急性散在性脳脊髄炎（Acute Disseminated Encepha—lomyelitis，以下ADEMと略す），および急性再発性散在性脳脊髄炎（Acute Relapsing Disseminated Encepha—lomyelitis以下，ARDEMと略す）は，多発性硬化症と関連した免疫学的機序により発症する中枢神経系の脱髄性脳脊髄炎である^2,5）．名前の如く病巣が散在性で急性に発症し，意識障害など重篤な症状で出現するのが特徴であるが，単一の病巣で発症したため，gliomaとの鑑別が困難であった症例を経験したので報告する．

A case of ARDEM presenting as a temporal lobe tumor is reported. A 19-year-old male was admitted to the hospital, because of headache, right homonymous hemianopsia, and general convulsion. CT scan and MR imaging revealed localized right medial temporal en-hanced mass lesion with surrounding brain edema. The craniotomy revealed an elastic hard ill-defined subcor-tical tumor. Histology showed a demyelinating process with perivascular lymphocyte cuffings. The patients' postoperative course was essentially uneventful until the 7th day when he developed fever, persistent hiccup, vertigo followed by obtundation and respiratory dis-tress. Repeated MR imaging revealed extensive lesions in the left thalamus, brain stem, upper spinal cord and cerebellum. The patient responded to steroid pulse ther-apy well. Six months later, however, he returned to the hospital with severe memory disturbance. Repeated MR imaging showed diffuse bilateral parieto-occipital white matter lesions. He again responded to steroid pulse therapy well. An immunosuppresant Mizoribine was added to his steroid therapy to prevent recurrence. With the advent of MR imaging, more non-surgical diseases such as multiple sclerosis and Behcet disease are visualized on imaging study. The differentiation of these diseases from intraparenchymal neoplasm is diffi-cult when they present as a single mass lesion. ADEM or ARDEM should be included in the list of such le-sions requiring differential diagnosis.