History In November 2012, a previously healthy 31-year-old woman was admitted to our hospital with a 2-month history of right-sided
numbness,
diplopia, and intermittent
nausea and
dizziness. She did not have a history of
fever,
weight loss,
headache,
photophobia, seizure, or extremity weakness. Physical examination revealed left abduction limitation and right-sided
hypoesthesia. Kernig and Brudzinski signs were absent, and pathergy test results were negative. Laboratory evaluation revealed normal complete and differential blood counts, normal serum chemistry, and normal immune function. Analysis of her serum was negative for antiaquaporin 4 antibody,
rheumatism antibody profile, and paraneoplastic profile. Serum analysis was also negative for human immunodeficiency virus type 1 and 2
RNA,
hepatitis B and C
antigen or antibody profile, and fluorescent treponemal antibody absorption. Cerebrospinal fluid (CSF) analysis revealed clear fluid, a normal
glucose level, an elevated
protein level (45 mg/dL; normal range, 20-40 mg/dL), and an elevated white blood cell count (10/mm3 [0.01 ×109/L]; normal range, 0-8/mm3 [{0-0.008} ×109/L]; 81% lymphocytes, 19% monocytes). No CSF-specific
oligoclonal bands were detected. Gram staining,
acid-fast staining, and
lactic acid and cryptococcal
antigen test results were negative. CSF did not grow any bacteria, fungus, or
acid-fast bacillus at culture. Spinal cord MRI, brain MR angiography, and CT of the chest, abdomen, and pelvis revealed normal findings (images not shown). Brain MRI and
gadolinium-enhanced (20 mL
gadopentetate dimeglumine, BeiLu Pharmaceutical, Beijing, China) MRI were performed. The patient's clinical symptoms and imaging findings responded to treatment with a high dose of
steroids. However, the patient's symptoms exhibited clinical and radiologic progression as she attempted to taper the
steroid dose. She arbitrarily stopped taking the
steroids and started traditional Chinese treatment instead. However, her condition was not controlled. In November 2013, she was readmitted with worsening
dizziness and
diplopia accompanied by
hearing loss,
tinnitus, slurred speech, drinking-induced
cough, walking instability, and involuntary outbursts of laughter and crying.
Dysmetria,
ataxia, brisk tendon reflexes, pathologic reflexes, and pseudobulbar signs were observed bilaterally. Repeated biochemical and immune tests did not yield positive findings. CSF analysis revealed mild lymphocytic
pleocytosis (white blood cell count, 8/mm3 [0.008 ×109/L]; 83% lymphocytes, 17% monocytes) and a slightly elevated total
protein level (46 mg/dL). Brain PET revealed diffuse high metabolism in the midbrain and pons (images not shown). Whole-body PET was negative for
malignancy (images not shown). Brain MRI and
gadolinium-enhanced MRI were performed. The patient's clinical symptoms and imaging findings improved
after treatment with a high dose of
steroids. Thereafter, intravenous
cyclophosphamide therapy was added after her condition deteriorated again when the
prednisone dose was tapered to 20 mg per day in March 2014. Her pontocerebral symptoms were relatively stable in the following year, with apparent diminishment of lesions in the brainstem and cerebellum observed at brain PET (images not shown). Follow-up MR images were obtained in July 2014. Subsequently, the patient exhibited clinical and radiologic aggravation. MR images were obtained again in July 2015 and February 2016. The patient underwent biopsy of the right frontal lobe, and a histopathologic examination was performed in August 2015. Afterward, her condition worsened, and she died in September 2016.