Episode 095: Introduction to CLL/SLL

Chronic Lymphocytic Leukemia (CLL) and Small Lymphocytic Lymphoma (SLL) represent the same malignant B-cell clone, distinguished primarily by whether the disease manifests in the peripheral blood or lymph nodes. Diagnosis requires an absolute lymphocyte count exceeding 5,000 and a characteristic immunophenotype, typically CD5, CD19, and CD200 positive. While smudge cells are common, they are not pathognomonic for CLL. Clinical management relies on risk stratification using IGHV mutation status and cytogenetic markers like 17p deletion, rather than outdated staging systems like Rye. Treatment is reserved for patients exhibiting symptomatic disease, such as B-symptoms, autoimmune cytopenias, or significant organomegaly. Because peripheral blood flow cytometry provides sufficient diagnostic and prognostic data, bone marrow biopsies are often unnecessary, though PET-CT imaging remains critical to rule out aggressive Richter’s transformation in symptomatic cases.