Lab Med Online.  2011 Jul;1(3):168-171.

A Case of Masked t(8;21) in Acute Myeloid Leukemia with Cytogenetic Abnormality of 45,X,-Y,t(8;17)(q22;p13)

• Shim H
• Lee YJ

Abstract

The t(8;21)(q22;q22) is one of the most frequent structural chromosomal anomaly found in AML, occurring in about 5% of all AML and in 10% of AML with maturation (M2). And approximately 3.4% of AML with t(8;21)(q22;q22) occurs as a complex chromosomal abnormality and occasionally shows discrepancy between cytogenetic and molecular genetic analyses. We report a case of 42 yr old male patient that revealed morphological characteristics of AML-M2 and karyotypic abnormality of 45,X,-Y,t(8;17)(q22;p13) without visible involvement of chromosome 21 by conventional cytogenetic study with masked t(8;21) identified by FISH using RUNX1/RUNX1T1 probes. FISH confirmed nuc ish (RUNX1T1x3),(RUNX1x3), (RUNX1T1 con RUNX1x1). According to the results of conventional cytogenetic and FISH analyses, the karyotype was revised to 45,X,-Y,t(8;17;21)(q22;p13;q22).

Keyword

AML-M2; Masked t(8;21); t(8;17;21)(q22;p13;q22)

MeSH Terms

Chromosome Aberrations
Chromosomes, Human, Pair 21
Cytogenetics
Humans
Karyotype
Leukemia, Myeloid, Acute
Male
Masks
Molecular Biology

Figure

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  Fig. 1 The blasts in (A) peripheral blood smear containing single Auer rod and in (B) bone marrow aspirate smear (Wright-Giemsa stain, ×1,000). They reveal large sized, round shaped nuclei with prominent nucleoli and moderate to abundant cytoplasm with azurophilic granules.

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  Fig. 2 The G-banded karyotype of the metaphases analyzed in the patient's bone marrow cells shows 45,X,-Y,t(8;17)(q22;p13). Arrows indicate abnormal chromosomes.

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  Fig. 3 FISH analysis for an RUNX1/RUNX1T1 probe. Interphase FISH shows an abnormal pattern of three-way variant translocation with two green signals (RUNX1), two red signals (RUNX1T1), and one yellow fusion signal in 98% of the nuclei examined.

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