Abstract: An 85y/o female patient was admitted to our hospital on Sep. 20th, 2010, with left hemiplegia for 10 days. On 2010 Sep. 10th&12th, she slipped down twice with no dizziness and conscious loss. On 13th, she had progressive left hemiplegia. Head MRI+DWI showed abnormal long T1 and T2 signals at bilateral frontal lobe, basal ganglia and brain stem. DWI high signal lesion was in right basal ganglia. Cerebral infarction and unknown cerebral lesions were diagnosed. She had HTN & DM for many years and chronic kidney disease for 2 years. Multiple thyroid nodules and cancer was suspected before. She was a retired nurse. On physical examination, she was clear. Left hemiplegia and hemihypesthesia were found with positive Babinski sign. After admission, routine laboratory tests were carried out. CBC, coagulation test, liver and kidney function were negative. Urine Protein was 0.25g/L. ESR 31mm/h，HCY 19.5umol/L, TC 6.72mmol/l，TG 1.76mmol/L，LDL-C 4.46mmol/L； Echo showed normal changes in the elders. TCD showed basal artery stenosis. Thyroid function：A-TPO 65.26 IU/ml，A-Tg 414 IU/ml. ANA and ANCA were negative. Anti-thrombosis and rehabilitation were given and the muscle strength improved. In November, she began to have dullness and poor cognition, progressive dementia. MRI showed bilateral frontal lobe lesion enlarged. Contrast MRI showed multiple abnormal enhanced nodules and MRS analysis suspected lymphoma. PET：The lesion in the brain is probable malignant. The patients’ son refused to do a biopsy. In December, she began to have epilepsy, with right spasm, and AEDs were given. EEG showed abnormal slow waves in the areas correspondence to MRI. On Dec. 12th, left hemiplegia and dullness progressed with muscle strength 0-1 degree. MRI showed lesions in left frontal lobe decreased, but that in right lobe increased. Neuron protection and dehydration was given. On Dec. 22th, LP was done. CSF pressure 90mmH2O，CSF white cell number was normal，Protein 0.9g/L，Oligoclonal Band（+）, cytology and pathogen were all negative. CSF TB-Spot was negative. Lymphoma was suspected and steroids were suggested. But she had recurrent lung infection, it was not used. 2011-1MRI showed bilateral lesions were decreased and less swollen. She was stable on the supportive treatment. After March, 2011, she got recurrent pneumonia and heart failure. She was intubated and given mechanical ventilation. In April, her renal failure progressed but her son refused dialysis. She gradually got into coma and died on Jun. 4th. Clinical diagnosis &Differential diagnosis: It was an old female patient with progressive dementia and hemiplegia. Neuroimaging showed bilateral lesion on the hemisphere and brain stem. The lesion became necrosis and atrophy as time passed with no treatment. The differential diagnosis should include malignancy, inflammation and metabolism disease. Malignant tumors such as lymphoma, gliomatosis cerebri, and intravascular lymphoma could progress slowly and cause dementia. The massive contrast lesion and low NAA on MRS supported malignance. Besides, high metabolism on PET also suggested malignance. No inflammatory cell in CSF with increased protein level was in correspondence with tumor.  Infectious and autoimmune inflammation, such as virus infection, prion infection, neurosyphilis, paraneoplastic limbic encephalitis, and vasculitis were important causes of dementia. Encephalopathy associated with abnormal thyroid function should also be thought about. But the negative result of serum screen and the imaging feature with massive abnormal enhancement ruled out most of the common etiologies. Lymphoma was highly suspected clinically.  Autopsy diagnosis: multi focies and extensive tumor cells in frontal lobe, insula lobe, basal ganglia, corpus callosum with CD20, BCL-2(+), CD8,CD68(-). Beside the tumor cells there were focies of lymphocytes with CD8, CD20 and CD68 (+). White matter: gliosis, disperse tumor cells, Leukoaraiosis. Pathological diagnosis: lymphomatosis cerebri.  Discussion Lymphomatosis cerebri was first reported by Bakshi et al in 1999. It was a special type of primary central nervous system lymphoma (PCNSL). PCNSL usually presented as a focal of multifocal mass lesion, with well defined boundary, with or without enhancement. The clinical manifestation was decided by the area involved. However, lymphomatosis cerebri involved widely in the brain, with months of progressive dementia. It should be an important differential diagnosis of CJD, limbic encephalitis, intravascular lymphomatosis and special encephalitis .The MRI feature of the disease was usually widely distributed white matter and cortex lesion in bilateral hemisphere, basal ganglia, thalamus, and brain stem with no mass. The enhancement was patchy or even none. The pathological feature was diffuse infiltration with tumor cells without formation of mass. The tumor cells were positive to CD20, with atypia and mitosis. Vascular cuffing was easily seen. Sometimes, tumor cells were mixed with reactive astrocytes and inflammatory lymphocytes, which should be differentiated with encephalitis. LFB stain could show white matter pallor, but no large area of demyelination .Lymphomatosis cerebri was sensitive to steroids. The apoptosis of tumor cells caused by steroids could lead to false negative pathological diagnosis. The treatment should include chemotherapy and radiotherapy.

Key words: Cognition disorders, Extremities, Lymphoma, Central nervous system neoplasms, Case reports

关键词: 认知障碍, 四肢, 淋巴瘤, 中枢神经系统肿瘤, 病例报告