Chronic myelomonocytic leukaemia with t(8;9)(p11;q34) in childhood: an example of the 8p11 myeloproliferative disorder?

We describe the case of a 10-year-old girl with chronic myelomonocytic leukaemia with the chromosomal translocation t(8;9)(p11;q34), who had developed tonsillar lymphoma as extramedullary involvement at the initial presentation. The cytogenetic study of the cells in both bone marrow and tonsils demonstrated t(8;9)(p11;q34), despite no malignant features in the bone marrow specimens. She developed acute leukaemic transformation 8 months after diagnosis during chemotherapy for lymphoma. Although etoposide reduced the number of blasts, t(8;9)(p11;q34)-bearing cells were not eradicated. Complete remission was obtained following an unrelated bone marrow transplantation. The clinical characteristics of this patient are similar to those of the patients with t(8;9)(p11;q34 or q32) or t(8;13)(p11;q11 or q12) reported previously. The unusual progression of the disease might be associated with the presence of (8;9)(p11;q34), suggesting a part in the 8p11 myeloproliferative syndrome.