Objective:To investigate the diagnosis and treatment of intravascular large B-cell lymphoma (IVLBCL).Methods:The clinical data of 1 patient with adrenal IVLBCL in Zhongda Hospital Southeast University in May 2020 were retrospectively analyzed, and the relevant literature was reviewed.Results:The patient was an elderly male with recurrent fever of unknown cause at initial stage, and was finally diagnosed as adrenal IVLBCL based on the results of laboratory, imaging and adrenal biopsy at different stages. After multiple courses of R-COP in combination with Bruton tyrosine kinase (BTK) inhibitor, the patient achieved complete remission.Conclusions:IVLBCL is rare and it lacks specific clinical symptoms. PET-CT and pathological biopsy can help in the diagnosis of it. R-COP combined with BTK inhibitor is effective in the treatment of biphenotype IVLBCL.