A Rare Case of Small Lymphocytic Lymphoma (SLL) Arising After Chronic Myeloid Leukemia (CML) in a Single Patient

Chronic myeloid leukemia (CML) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) are among the most common types of leukemia in adults. However, the sequential development of CLL/SLL following a prior diagnosis of CML in the same individual is exceedingly rare. We present the case of a 65-year-old male initially diagnosed with Philadelphia chromosome-positive CML, who subsequently developed SLL, the tissue-based counterpart of CLL. His CML was initially managed with bosutinib, later switched to dasatinib due to side effects, resulting in both cytogenic and molecular response. Two years later, he was diagnosed with SLL. This report explores the potential molecular mechanisms underlying the coexistence of these distinct hematologic malignancies and highlights important considerations in the selection of appropriate treatment strategies.