Abstract:Objective To improve the understanding of Richter syndrome (RS) through analyzing the risk factors, treatment and prognosis of RS. Methods The clinical data of one patient with small lymphocytic lymphoma (SLL) transformed to RS was retrospectively analyzed with a review of the relevant literature. Results The patient presented with multiple enlarged lymph nodes. According to the lymph node biopsy at the first visit, the morphology, number, and immunophenotype of mature small lymphocytes in peripheral blood and bone marrow were consistent with the diagnosis of SLL before transformation. The treatment effect was acceptable before transforming to RS. However, R-CHOP chemotherapy was applied and achieved only partial remission after transforming to RS. Conclusion In the treatment and development of chronic lymphocytic leukemia/SLL, histological transformation of RS may occur, even it is rare. However, the mechanism of transformation is not clear. Chemoimmunotherapy, hematopoietic stem cell transplantation and new drug application can be used for treatment after transformation, but it is difficult to propose a standard and optimized method for RS patients according to the existing data, and the treatment effect is poor. Clinicians should pay attention to patients with risk factors for transformation of RS so as to improve the survival rate of the patients through early diagnosis and treatment.