Chronic lymphocytic leukemia/small lymphocytic lymphoma and Burkitt lymphoma: A unique case of a composite lymphoma of different clonal origins.

The occurrence of two different types of lymphoma simultaneously in the same location in a patient is uncommon. We recently encountered a unique case in a 61-year-old man. The histopathological analysis confirmed the coexistence of 20% chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and 80% Burkitt lymphoma (BL) in the right submaxillary lymph node. To the best of our knowledge, this is the first documented case of composite lymphoma (CL) occurring in a lymph node, involving both CLL/SLL and BL. We will explore the clonal relationship between these two components and review the literature to discuss their abnormal immunohistochemical phenotypes.