Introduction and presentation
Burkitt (BL) and lymphoblastic lymphomas (LBL) are highly aggressive diseases with distinct natural histories and clinical presentations. BL mostly occurs in the first two decades of life and accounts for 1–2% of all lymphomas. Three clinical variants are recognized: (1) endemic BL, which is primarily found in equatorial Africa; (2) sporadic BL, which presents worldwide but is the most common type in western countries; and (3) immunodeficiency-associated BL, which is associated with HIV infection. There are important clinical differences in these variants (Table 11.1), with endemic BL involving the jaw, orbit, and paraspinal regions in half of the cases as well as the mesentery and gonads, while sporadic BL mostly involves the distal ileum, cecum, and/or mesentery, and rarely the jaw. When bulky or disseminated disease is present, extranodal involvement of the ovaries, kidney, breasts, and/or CNS may be seen. Clinical presentation in a Berlin–Frankfurt–Munster Group (BFM) series of 152 pediatric patients included advanced stage (III/IV) disease in 38%, bone marrow involvement in 33%, and central nervous system (CNS) disease in 4%. Of the patients in this series, 27% presented as acute leukemia, referred to as the L3 subtype of acute lymphoblastic leukemia (ALL) within the French-American-British (FAB) classification, or B-ALL. BL infrequently presents in adults, but does occur with increased frequency in patients with HIV infection.
LBL is most commonly a malignancy of T-cell precursor cells, and, as such, it is identical to T-cell acute lymphoblastic leukemia (T-ALL).