中枢神経系に浸潤したTリンパ球増殖性疾患（T-cell Lymphoproliferative Disorder）の2例

T-cell Lymphoproliferative Disorder Involving the Central Nervous System in Two Cases

I．はじめに

　リンパ増殖症（lymphoproliferative disorder：LPD）はリンパ腫（lymphoma）に類似した疾患であり，時に中枢神経（central nervous system：CNS）に浸潤する予後不良の疾患である^1,3,12）．原発性CNS-lymphomaやLPDは高齢者に発症することが多いが，続発性LPDは年齢に関係なく先天性免疫不全症，移植医療における強力な免疫抑制療法，がん化学療法，HIV感染症例などに伴って発症する^1,3,10-12）．原発性，続発性ともにほとんどがB細胞由来でありT細胞，natural killer（NK）細胞起源であることは極めて稀である^2,10）．

　今回，原発性T-cell LPDと慢性活動性EBウイルス感染症（CAEBV）に伴う続発性T-cell LPDのCNS浸潤を2例経験し，早期の組織診断と免疫化学療法が有効であったので報告する．

Lymphoproliferative disorder (LPD) sometimes occurs in immunosuppressive patients. B-cell prolifera-tion is predominantly seen in patients with LPD and T-cell proliferation is rare. We here report two pa-tients with T-cell LPD involving the central nervous system (CNS). A 7-year-old boy developed increased intracranial pressure and computed tomography showed a ring-enhanced mass lesion in the right frontal lobe. A 10-year-old boy developed gait disturbance and magnetic resonance imaging showed a non-en-hanced lesion in the left parietal lobe. Radiological findings could not differentiate CNS-LPD from other intracranial diseases. Only histologic examination could diagnose LPD in both cases, and Epstein-Barr virus associated RNA was found in the infiltrated T-cell of the latter case. Although chemotherapy with antitumor agents was effective for remission of LPD in both cases, both patients died 3 years after their operations. As CNS-LPD shows rapid progression and frequently results in fatality, this disease requires immediate histologic diagnosis followed by extensive chemotherapy.