Richter syndrome, a diagnostic challenge: a case report.

Abstract

Richter syndrome (RS) represents an uncommon but highly aggressive transformation of chronic lymphocytic leukemia (CLL) into a high-grade lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). We report the case of a 78-yearold male with a history of Rai stage IV CLL, without baseline molecular profiling, and with sub-optimal response to prior rituximab-chlorambucil. He was admitted due to a respiratory infection with a torpid course, accompanied by worsening cytopenias, marked elevation of lactate dehydrogenase (LDH), and hypogammaglobulinemia. Abdominal CT revealed a retroperitoneal lymph node conglomerate, and lymph node biopsy confirmed transformation to DLBCL (Richter syndrome). Despite initial bridge therapy with acalabrutinib (a BTK inhibitor) followed by R-CHOP immunochemotherapy along with tumor lysis prophylaxis, the patient developed severe tumor lysis syndrome, refractory acute kidney injury requiring hemodialysis, and profound pancytopenia, leading to a fatal outcome. This case illustrates the diagnostic challenge posed by RS when presenting atypically without peripheral lymphadenopathy, emphasizing the importance of early suspicion, clonality determination, and balanced therapeutic strategies.