RESUMO
Primary central nervous system lymphoma (PCNSL) is a rare disease that can be confused with Wernicke encephalopathy (WE). We have reported here the case of a 31-year-old malnourished man who presented with headache, fever, vomiting, diarrhea, and confusion. His imaging and laboratory findings were indicative of WE. His condition improved after treatment with a high dose of vitamin B1 and intravenous administration of methylprednisolone. However, after continuing to take vitamin B1 for 2 weeks, his symptoms and neuroimaging findings worsened. Increased standardized uptake values of positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG-PET) and interleukin-10 (IL-10) in the cerebrospinal fluid led to the diagnosis of PCNSL. After treatment with methotrexate and calcium leucovorin, the symptoms and neuroimaging abnormalities disappeared at the 6-month follow-up examination. The possibility of PCNSL should be considered if the routine treatment for WE are ineffective. 18F-FDG PET and IL-10 may provide a new method for the early diagnosis of PCNSL.