INTRODUCTION AND PRESENTATION

Burkitt's (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: endemic BL, which is primarily found in equatorial Africa and Papua New Guinea, sporadic BL, which presents worldwide but is the most common type in Western countries, and immunodeficiency-associated BL, which is associated with HIV infection. There are important clinical differences in these variants (Table 13.1), 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 central nervous system (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 CNS disease in 4%. Overall, 27% of the patients in this series presented as acute leukemia and are usually referred to as the L3 subtype of acute lymphoblastic leukemia (ALL) within the French–American–British (FAB) classification. 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).