脳原発悪性リンパ腫の1剖検例—その全身への転移形式についての考察

AN AUTOPSY CASE OF PRIMARY INTRACRANIAL MALIGNANT LYMPHOMA SHOWING EXTRACRANIAL DISSEMINATIONS

　長期間中枢神経症状のみで経過し，末期に企身に転移したと思われる脳原発悪性リンパ腫の1剖検例を報告した。症例は50歳の男性で，自発性の低下で始まり，痴呆，意識障害等が進行した。CT上両側脳室近傍に造影効果陽性の低吸収域を呈したが，自然経過で一部陰影が消えたり，造影効果の全く消失した低吸収域のみの時期があった。悪性リンパ腫を想定し，治療前に施行した胸腹部CT，各種シンチ・エコー，消化管造影およびファイバー，骨髄穿刺，リンパ管造影などによる全身の詳細な検索にて異常は認められなかった。しかし，脳原発悪性リンパ腫を疑い，放射線療法により臨床症状やCT所見が一時軽快したが，やがて脳出血，下痢，胸水，腹水を伴い死亡した。全経過は約2年。経過中，モノクローナル抗体を用いた髄液細胞の解析により，B cell typeのリンパ腫と診断された。剖検にて，脳とともに全身の広範な悪性リンパ腫（L26陽性）が認められ，生前の臨床的全身検索とあわせ，脳から全身への転移が推察された。

An autopsy case of malignant lymphoma of the central nervous system which showed extracranial disseminations was presented.

A 50-year-old man developed mental and phy-sical slowness over one year prior to admission followed by dementia and consciousness distur-bance without general physical symptoms. Physical examination on admission showed no lymph node enlargement, hepatomegaly, splenomegaly, or abdo-minal mass. Neurological examination revealed mild dementia, left positive Babinski and Chad-dock reflexes, and bilateral positive frontal lobe signs. CT scan revealed low densitry areas with contrast enhancement in the white matter of the bilateral parietal lobes adjacent to the trigon of lateral ventricles. Without any therapy, the low density area in the left cerebral hemisphere on CT scan disappeared and the low density area in the right cerebral hemisphere became unenhanced. Any other lesions except brain were found des-pite of the extensive systemic examinations inclu-ding schintigrams, echograms, gastrointestinal exa-minations, body CT scan, aspiration of bone mar-row, and lymphography. Prymary intracranial ma-lignant lymphoma was suspected and treated with steroid without any response. Subsequent radiationtherapy made a transient imporovement. But a few months later, the brain lesions gradually wor-sened, followed by general physical deterioration with diarrhea, pleural fluids, and ascites. Cytolo-gic study of cerebrospinal fluid revealed neoplas-tic lymphocytes with atypical nuclei containing conspicuous nucleoli and mitosis, which were iden-tified as B cell type malignant lymphoma by analy-sis using monoclonal antibody. The patient died of cardiac failure about two years after the ini-tial symptom. The autopsy disclosed malignant lymphoma (diffuse lymphoma, large cell type, non cleaved, B cell type) of the brain with extracra-nial spreading, involving lungs, liver, kidneys, adrenal glands, and submucosal regions of esopha-gus, stomach, and small intestine. Extensive tumor growth was noted in the retroperitoneal lymph nodes. The bone marrow or the spleen was not involved. Considering the clinical course, systemic examinations and autopsy findings, this case was probably a primary intracranial malignant lympho-ma with extracranial involvement. A primary int-racranial malignant lymphoma with dissemination to extracranial regions has not been well docu-mented in the past. Clinical presentation of only mental disturbance over one year without focal neurological symptoms and increased intracranial pressure, and CT scan findings of the low density area without contrast enhancement effect in the course of this case were of rare occurrence and interesting. The importance of cerebrospinal fluid cell analysis using monoclonal antibody to detect B cell type lymphoma was also to be stressed.