Diffuse large B-cell lymphoma with central nervous system symptoms during the maintenance therapy of acute lymphoblastic leukemia: a case report and literature review.

Background: Diffuse large B-cell lymphoma (DLBCL) secondary to acute lymphoblastic leukemia (ALL) is a rare disease with poor prognosis, usually attributed to delayed diagnosis. To date, only four cases of ALL developing DLBCL have been reported, while none of them exhibiting central nervous system (CNS) symptoms.

Case Description: Here, we report an unusual case of a 15-year-old boy diagnosed with ALL and treated based on the SCCLG-ALL 2016 protocol. While he was receiving maintenance treatment, the patient developed dizziness and vomiting. An Epstein-Barr virus (EBV)-positive DLBCL with CNS involvement was diagnosed from inguinal lymph nodes biopsy, EBV DNA tests and head magnetic resonance imaging (MRI). Meanwhile, a dramatic decrease of immune cells and immunoglobulin was detected in the occurrence of DLBCL. He received therapy based on SCCCG-NHL-2017 protocol immediately after the diagnosis.

Conclusions: We present the first retrospective report of four cases of non-Hodgkin lymphoma (NHL) secondary to ALL between 1990 and 2022. The pathogenesis of secondary DLBCL may be related to infection, immunodeficiency, genetic susceptibility, and treatment. Thus, the detection of EBV DNA during the full course of ALL therapy and genetic tests were needed in the occurrence of secondary DLBCL. Given to the rare rate and insufficient treatment experience, longer follow-up and enough sample size are needed.