Correspondence

Abstract

We read with interest the report of Harada et al (1995) about a specific chromosome abnormality in CD7-positive acute myeloid leukaemia (AML):t(4;12)(q11;p13).The three cases (two AML-M0 and one AML-M2) evidenced a three-lineage dysplasia, absent or low myeloperoxidase activity, a normal or slightly decreased platelet count and a peripheral blood and bone marrow basophilia in two cases. The immunophenotype was CD7 þ , CD13 þ , CD34 þ , HLD-DR þ and the authors suggested that t(4;12)(q11;p13) is restricted to CD7-positive AML.Here we report the case of an 82-year-old man with a t(4;12)(q11;p13) and a CD7-negative AML with a unusual mature lymphoid morphological presentation in the peripheral blood. The peripheral blood showed 67 × 10 9 /l WBC with 80% small mature lymphoid-like cells, suggesting the diagnosis of chronic lymphocytic leukaemia (Fig 1A). The immunophenotype, performed on peripheral blood, was negative for T and B lymphoid markers and a complementary study showed positivity for CD117 (c-kit), CD13, CD33, CD11a, CD34 and CD56, with negativity for HLA-DR, CD16 and CD7. Immunological features were thus consistent with the HLA-DR ¹ , CD33 þ , CD56 þ , CD16 ¹ myeloid/natural killer cell entity (AML/NK; Scott et al, 1994). Bone marrow aspirate revealed 90% of cells with evident blastic morphology. Some of them presented rare small azurophilic granulations. Low myeloperoxidase activity (5%) was present in agreement with the FAB criteria for AML-M1.A t(4;12)(q11;p13) was evidenced in 20 mitoses by karyotype as a sole chromosomal abnormality using Q and R banding (Fig 1B-C). A dicentric (4;12) was eliminated by C banding.Only one case of AML with a mature lymphoid morphological presentation has been described (Matutes et al, 1987). The immunophenotype was CD13 þ , CD33 þ , CD117 þ , with positivity for CD7, negativity for CD16, but no data concerning HLA-DR and CD56. Karyo-type evidenced monosomy 5 and 21, t(2;13)(q23;q14), t(4;17)(p12;p11) and, as a secondary abnormality, a dicentric (4;12)(p12;?p12) with perhaps a breakpoint on 12p which was similar to our case.On the other hand, another case of t(4;12)(q11;p13) has been described in a relapse of AML-M4 secondary to a busulphan-treated polychthaemia vera, but the immunophenotype was not performed (den Nijs et al, 1989). In the three cases of t(4;12) described by Harada et al (1995), CD56, CD11a and CD16 were not tested but HLA-DR was positive.Altogether these data show that t(4;12)(q11;p13) is presently restricted to AML although possibly not to CD7 þ AML, as demonstrated by our case.Breakpoints in 12p13 have been described in myeloid malignancies and the TEL gene, a member of the family of ETS transcription factors located on 12p13, has been shown to be fused to the PDGF-Rb gene in t(5;12)(q33;p13) chronic myelomonocytic leukaemia (Golub et al, 1994), fused with the MN1 gene in t(12;22)(p13;q11) myeloproliferative disorders (Buijs et al, 1995) and disrupted in myelodysplastic syndromes with t(3;12)(q26;p13) (Raynaud et al, 1996). Whether the TEL gene and ...

Acute myeloid leukemia with t(4;12)(q12;p13): report of 2 cases

“…The translocation presented as either a single chromosomal abnormality or combined with other abnormalities ( Table 1 ) [ 1 3 4 5 6 7 8 10 11 12 13 14 15 ]. The karyotype of the first patient was 46,XY, t(4;12)(q12;p13),del(5)(q22q35), and del(5q) is a common chromosomal abnormality in myelodysplastic syndrome and in AML with myelodysplasia-related changes.…”

“…TO THE EDITOR: Acute myeloid leukemia (AML) with t(4;12) is rare, but its unique morphologic and clinical characteristics have been described in several reports [ 1 2 3 4 5 6 7 8 ]. Most cases show CD7 expression, low or absent myeloperoxidase activity, basophilia, unique blast morphology, dysplastic features, and poor prognosis [ 1 2 3 4 5 6 7 8 ]. Harada et al reported that the incidence among adults is 0.6% [ 1 2 ].…”