原发性中枢神经系统淋巴瘤（PCNSL）是一种罕见、侵袭性的额外淋巴瘤，占原发性脑肿瘤的1-2％，在没有系统性侵犯的情况下发展于脑、脊髓、眼睛或蛛网膜区。PCNSL的免疫能力患者总发病率仅为0.47 / 10万年。约有10-20％的患者涉及眼部，约三分之一的患者具有多发性神经系统疾病。总体长期生存率仅为20-40％，这是因为PCNSL的管理受制于药物跨越血脑屏障（BBB）的能力。我们为一名免疫能力患者呈现了一个B细胞中枢神经系统淋巴瘤，该患者治疗反应强，与化疗有关。一名35岁的男子在入院前4小时突然昏迷。他在3个月内经历头痛和视力模糊，并发作癫痫。检查结果显示：格拉斯哥昏迷评分E2 M3失语，右半身瘫痪，视乳头水肿，左眼视野/右眼视野：无光。其他体检正常。实验室检查Hb 10.7 g / dl，LDH 446 U / L和D-dimer 3.21ug / ml。风疹IgG 76.9，CMV Ig G 245.6，HSV IgG和IgM阴性，HIV测试不反应，弓形虫IgG和弓形虫IgM阴性，HbsAg和HCV测试阴性。脑MRI和MRI光谱：丘脑核左侧-侧脑室区域7.08 cm x 4.75 cm大小的分叶状肿块，胆碱/ NAA比值为5-9，胆碱/肌酸比值为6-11，怀疑是恶性肿瘤或淋巴瘤。 MRI全脊柱：C4-C5椎间盘突出。胸部和腹部CT扫描正常。骨骼调查正常，脑电图：左侧颞叶癫痫样。脑脊液：胶质反应高于恶性肿瘤。患者接受了颅骨切开和基底节活检病理解剖和IHC显示弥漫性大细胞B细胞淋巴瘤（NHL）非生殖中心，CD 20 +，Ki 67 95％（高级别），CD 45 +，CD 3-，BCL6 +，Mum 1 +。我们采用RMP方案（Rituximab 375 mg / m2，第1天，15天和29天，高剂量甲氨蝶呤（HDMTX）3000mg / m2，第2天，16天和30天，以及65mg / m2，第3-12天）启动感染治疗，因为Procarbazine在Palembang不可用，所以我们改用Dacarbazine 375mg / m2，第3天，17天和31天）。地塞米松5mg / 6小时，并已完成低剂量全脑放疗以作为安抚疗法。在免疫能力患者中PCNSL是一种罕见的侵袭性额外淋巴瘤。在这种特殊情况下，高剂量甲氨蝶呤化疗在特别是对于此患者表现出GCS E4M5V6并在2个疗程化疗后康复神经缺陷的患者中取得了回应。

Primary CNS Lymphoma (PCNSL) is a rare form aggressive extra nodal     non-Hodgkin Lymphoma (NHL) that comprising 1-2% of the primary brain tumors that develops in the brain, spinal cord, eye or leptomeningeal area without evidence of systemic involvement. The overall incidence of PCNSL with immunocompetent patients is only 0,47/100.000 year in PCNSL. Approximately 10-20% of patients have ocular involvement and around one third have multifocal neurological disease. Overall long-term survival rate only 20-40%, this is because the management of PCNSL is limited to ability of the drug due to cross the blood brain barrier (BBB). We present a B-cell central nervous system lymphoma in an immunocompetent patient who treat responses with chemotherapy.          A 35-year-old man presented to our hospital with suddenly unconscious 4 hours before admission. He was experiencing headache and blurred of vision withing 3 months and have episode seizure. On Examination, GCS E2 M3 Aphasia, Hemiparesis dextra, papil edema, VOD/VOS: NLP. The other physical exam was normal. Laboratory tests  Hb 10,7 g/dl, LDH 446 U/L, and D-dimer 3,21ug/ml.  Rubella IgG 76,9, CMV Ig G 245,6 and, HSV IgG and IgM negative, HIV test non-reactive, Toxoplasma IgG and Toxoplasma IgM negative, HbsAg and HCV test negative. Brain MRI and MRI Spectroscopy: Lobulated mass size 7,08 cm x 4,75 cm at caudates nucleus sinistra-periventricular lateralis sinistra, Cholin/NAA ratio: 5-9, Cholin/Creatin ration 6-11 suspect malignancy dd/Lymphoma. MRI whole spine: Bulging discus intervertebral C4-C5. Chest and Abdomen CT-Scan are normal. Bone Survey normal, EEG: Epileproform left temporal. Cerebrospinal Fluid: Gliosis reaction sup malignancy.The patient underwent craniotomy and biopsy Pathology Anatomy and IHC Basal Ganglia revealed a Diffuse Large B Cell Lymphoma (NHL) Non-Germinal Center, CD 20 +, Ki 67 95% (High Grade), CD 45 +, CD 3 -, BCL6 +, Mum 1+. The patient we give induction therapy with RMP Regimens (Rituximab 375 mg/m2, day 1, 15 and 29, High Dose Methotrexate (HDMTX) 3000mg/m2 day 2, 16 and 30, and Procarbazine 60mg/m2 day 3-12) because Procarbazine in not available in Palembang we change to Dacarbazine 375mg/m2 days 3,17 and 31), Dexamethasone 5mg/6 hours, and has finished  Low Dose Whole Brain Radiotherapy for consolation therapy. PCNSL is rare form aggressive extra nodal NHL, especially in Immunocompetent patient. In this particular case of patients High Dose Methotrexate Chemotherapy has achieved high respond especially for this patient that showed GCS E4M5V6 and recovery neurological deficit after 2 cycle chemotherapy.