We read with interest the insightful comments of Dr Wright, who is in a unique position to evaluate the historical evolution of the definition of Burkitt’s lymphoma (BL) and its variants.1His observations emphasize the importance of precise disease definitions for biological and epidemiological studies. These principles were used by the Revised European-American Classification of Lymphoid Neoplasms (REAL), which proposed that disease entities should be defined by a constellation of morphological, biological, and clinical features.2
The World Health Organization (WHO) classification will recognize several variants of BL, all of which are high-grade B-cell lymphomas that share deregulation of the c-myc, leading to the characteristic histological and clinical features of BL.3 In addition to endemic BL, sporadic BL, and AIDS-associated BL, as defined by Dr Wright, the WHO scheme will include an “atypical or pleomorphic” variant of BL. This subtype includes some cases that would have been diagnosed as “Burkitt-like” lymphomas in the REAL classification. These high-grade lymphomas show greater nuclear pleomorphism than classical BL, with occasional larger lymphoid cells resembling centroblasts. However, 100% of the cells are in cycle, and treatment recommendations are similar to those of classical BL. This variant is closely related to sporadic BL in its clinical and epidemiological features. Finally, the WHO classification recognizes that some BL may present with preferential involvement of the bone marrow and peripheral blood. Such cases were diagnosed as the L3 subtype of acute lymphocytic leukemia in the French-American-British Cooperative group classification.4
