Cytogenetic findings in pediatric T-lymphoblastic lymphomas: one institution's experience and a review of the literature.

Cytogenetic analyses of lymphomas commonly reveal nonrandom chromosomal abnormalities, but there are relatively few reports in childhood lymphoblastic lymphoma (LL). We retrospectively reviewed G-banded karyotypic analyses performed at Arkansas Children's Hospital between 1990 and 2004. Six children (2 to 20 years old) had LL that presented as mediastinal or cervical masses and had a T-cell immunophenotype and clonal abnormalities. The cytogenetic findings in these 6 patients were as follows: 46,XX,-7,inv(9)(p11q12),der (12)t(7;12)(q11.2;p13),t(16;18)(p13.1;q21),+22 in patient 1; 47,XX,+9,del(9)(q11q22)x2 in patient 2; 72-119, XY,+X,+1,+1, inv(2) (p11q13),-3,+5,+6,+7,+10,-12,-16, -21,-21,-22,+mar in patient 3; 48,XY,+5,+20,t(7;9) (q32;q34) in patient 4; 47 approximately 48,XX,der(10)t(10;14)(q23; q11.2),+12, del(12)(p12)x2, -14,del(16)(q22q22),+?add (19)(p13.3) in patient 5; and 48 approximately 49,XY,+7,+8,t(11;19) (q23;p?13.3),+der(19)t(11;19)[cp20] in patient 6. Eleven chromosome breakpoints in 6 of our patients (7q11, 12p13, 16p13, 18q21, 9q11, 2p11, 2q13, 7q32, and 7q23) have been reported in other patients with acute lymphoblastic leukemia or LL and involved regions containing TEL, ABL, E2A, MLL, and T-cell receptor-alpha genes. A review of the cytogenetic findings of these and other cases of LL reveals that clonal aberrations are common and most frequently involve T-cell receptor gene regions. The aberrations show some features similar to those of acute lymphoblastic leukemia and are not unique to LL, thus furnishing additional evidence of the equivalence of these two diseases. The cytogenetic features of LL may be helpful in the diagnosis of pediatric lymphomas and undifferentiated neoplasms.