SUMMARY

Acute myeloid leukemia is a hematological malignancy of adults older than 55 years old with a major incidence in males, however it is also seen in children and older adults (6). Its main pathological characteristic is the excessive accumulation of precancerous non lympliocytic cells in the marrow, itself in peripheral blood and in other tissues (3).

According to FAB, AML is divided in eight subtypes and two thirds of the AML patients show abnormal karyotypes in the bone marrow which let us to understand the great help of cytogenetics in the diagnosis and management of these kinds of leukemias. It is well known the non-random involvement of t(8;2l) ni the old group M2; t(15;17) in acute promyelocytic leukemia (variants and PML/RARalpha); inv(16)(p13q22) in AML, with abnormal bone marrow eosinphils and t(9;l1) in AML with 11q23 abnormalities. It has been found also monosomy 7 and trisomy 8 among other secondary structural abnormalities related to this particular kind of leukemias,

However, conventional cytogenetics has faced problems in the identification of complex chromosomal rearrangements. Multicolor FISH is a technique that offers the possibility to identify marker chromosomes. In our case, we present a patient with flow cytrometric studies showing the possibility of AML. G-banding showed a karyotype 46,XY, add(7q) showing additional material of unknown origin at approximately band q35 of chromosome 7. MULTICOLOR FISH solved our problem. We saw a der(7)t(1;7)(q3 I;q3 1). This unbalanced rearrangement results in loss of long arm sequences on chromosome 7 (partial monosomy) from q31 to qter and gain of long arm sequences of chromosome 1 (partial trisomy) from q31 to qter. Involvement of both chromosomes (1 and 7) correspond with a clonal neoplastic process and correlates with AML. The patient is being treated and future follow ups programmed.

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