Tumor Lysis Syndrome Caused by Unrecognized Richter's Transformation of Chronic Lymphocytic Leukemia: Treatment With Venetoclax for Suspected Disease Progression.

Juan Jose Chango Azanza,Neiha Kidwai,Vinay Mathew Thomas,Nerea Lopetegui Lia,Paola Michelle Calle Sarmiento

doi:10.7759/cureus.8145

Abstract

Richter’s transformation (RT) is defined as the transition of chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL) into an aggressive lymphoma. The conversion generally leads to diffuse large B-cell lymphoma (DLBCL), but more aggressive forms such as Hodgkin lymphoma (HL) can also occur. RT is a rare complication of CLL. RT can be confused with CLL progression. Its identification is crucial because the management of lymphoma and CLL differ from each other. Furthermore, the use of certain agents for CLL such as venetoclax increases the risk of tumor lysis syndrome (TLS) in neoplasms with rapid replication such as DLBCL or CLL with hyperleukocytosis (blast crisis). We present the case of a 76-year-old man with a history of CLL on chemotherapy who developed fatigue, malaise, night sweats, chills, and unintentional weight loss for which he was started on treatment with venetoclax due to suspected clinical progression of his disease. The patient developed TLS, requiring hospitalization, and he was found to have an acute blast crisis. Also, his CLL was found to have been transformed into an aggressive DLBCL. This case highlights the importance of differentiating a true progression of CLL from RT into an aggressive lymphoma given that treatment would be different for the two and the prognosis with the transformation is worse.

Highlights

Chronic lymphocytic leukemia (CLL) is a common hematologic malignancy
We present the case of a patient who developed a suspected progression of CLL for which he was treated with venetoclax; he went on to develop tumor lysis syndrome (TLS)
Richter’s transformation (RT) is a known complication of CLL/small lymphocytic leukemia (SLL) in which an aggressive lymphoma such as a diffuse large B-cell lymphoma (DLBCL) arises

Summary

Introduction

Chronic lymphocytic leukemia (CLL) is a common hematologic malignancy. Richter’s transformation (RT) or syndrome is defined as the transition of CLL or small lymphocytic leukemia (SLL) into an aggressive lymphoma such as diffuse large B-cell lymphoma (DLBCL) or Hodgkin lymphoma (HL) [1]. The last visit to his oncologist had been four days prior, and he had been started on venetoclax (a BCL-2 or B-cell lymphoma 2 inhibitor) due to suspicion of clinical progression of his disease His oncologist noted abnormal laboratory results and referred him to the emergency department. The repeat microscopy showed a WBC count of 250,000/mm with marked lymphocytosis of abnormal medium to large-sized lymphoid cells (Figure 3) These lymphocytes were characterized by an ovoid nucleus, prominent nucleoli, delicate chromatin, and increased basophilic cytoplasm (Figure 4). A difference in cell size can be appreciated when comparing the normal-sized lymphocytes (yellow arrow) to the pathologic lymphoid cells This phenomenon termed "Richters transformation" demonstrates the shift from normal-sized lymphocytes seen in chronic lymphoblastic leukemia into larger cells observed in diffuse large B-cell lymphoma.

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