What is the lymphoma equivalent of chronic lymphocytic leukemia (CLL)?

Small lymphocytic lymphoma (SLL) is considered the lymphoma equivalent of chronic lymphocytic leukemia (CLL) because both conditions arise from the same type of B-cell lineage and have similar clinical and pathological characteristics. CLL is primarily characterized by the proliferation of small, mature lymphocytes in the peripheral blood, while SLL presents primarily as lymphadenopathy due to the accumulation of these lymphocytes in lymphoid tissues.

The two entities are differentiated primarily by their presentation; CLL often has a greater number of circulating lymphocytes, whereas SLL is defined by the presence of lymphoid tissue involvement without significant peripheral blood lymphocytosis. Both conditions share similar genetic mutations and respond to similar treatments, further establishing their close association.

In contrast, the other options listed represent distinct types of lymphoma or diseases with different characteristics and underlying biology. Large cell lymphoma and aggressive B-cell lymphoma refer to more aggressive forms of lymphoma that have significantly different presentations and treatment approaches than CLL or SLL. Follicular lymphoma is a type of indolent lymphoma that originates from germinal center B-cells and has a different pathophysiological mechanism and clinical course.