LAUSR

© BMJ Publishing Group Limited 2022. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A 41yearold man was referred to our hospital with a 2month history of recurrent fever, sweating, cough and weight loss despite antibiotherapy treatment. At the time of admission, laboratory examinations revealed significant thrombocytopaenia and elevated levels of lactate dehydrogenase. Various bacterial cultures were negative. CT revealed normal findings of the bilateral lungs (figure 1A) and massive splenomegaly (figure 1C). A following examination using 18Ffluorodeoxyglucose (FDG) positron emission tomography (PET) CT showed diffuse high uptake in the spleen (figure 1D), and the bilateral lungs (figure 1B). Because of significant thrombocytopaenia and massive splenomegaly, diagnostic splenectomy was performed. Spleen specimen was examined pathologically, and intravascular large Bcell lymphoma (IVLBCL) was diagnosed. Pretreatment cranial MRI was performed due to the development of confusion in the patient. MRI showed abnormal signal areas in the pons on T2weighted axial image (T2WI) (figure 1E) and right frontal lobe on FLAIR axial image (figure 1F). These findings were suspicious for IVLBCL involvement. After treatment, complete remission (CR) was confirmed with PET CT and cranial MRI. PET CT demonstrated disappearance of FDG uptake in the bilateral lungs (figure 2A). Cranial MRI showed disappearance of the lesion in the pons (figure 2B) and regression of the lesions in the right frontale lobe (figure 2C). PET CT and cranial MRI which performed 17 months later confirmed that CR had been maintained. IVLBCL is an aggressive lymphoma with poor prognosis due to variable and nonspecific symptoms and delays in diagnosis. The most common symptoms are fever, weight loss and sweating. IVLBCL showes a pulmonary FDG uptake even in the absence of CT abnormalities. Also, most patients with IVLBCL present abnormal findings on pretreatment cranial MRI even in the absence of neurological symptom. These findings are infarct like lesions, nonspecific white matter lesions, meningeal enhancement, masslike lesions and hyperintense lesions in the pons on T2WI. Especially, hyperintense lesion in the pons on