An Idic(7)(q11.2) Resulting in Two Copies of 7p and Deletion 7q: A Rare Cytogenetic Event in a Case of Acute Myeloid Leukemia.

A 67-year-old male patient was diagnosed with acute myeloid leukemia (AML) in April 2018. Chromosome analysis showed an abnormal male karyotype with an isodicentric chromosome 7q resulting in deletion 7q and two copies of 7p and a derivative chromosome 18 in 13 of the 20 metaphase cells examined. This karyotype was described as 46,XY,idic(7)(q11.2),der(18)t(1;18)(q23;q21.1)[13]/46,XY[7]. Additionally, subsequent sequencing analysis displayed FLT3-ITD and RUNX1 mutations (data not shown). The bone marrow showed an overwhelming number of blast cells, with co-expression of CD34, CD117, TdT, MPO, CD7, CD13, CD33, CD38, CD19, and HLA-DR. Molecular cytogenetic studies showed a deletion of one RELN/TES (7q22/7q31) signal in 80.5% of nuclei and a gain of a BCR/ABL1 (22q11.2/9q34) signal in 3.5% of interphase nuclei examined. These findings were described as nuc ish(RELN,TES)x1[161/200],(ABL1x2,BCRx3)[7/200], (EVI1,TAS2R1,EGR1,DEK,MYC,NUP214,KMT2A,DLEU1,DLEU2,Clone 163C9,PML,CBFB,RARA,PTPRT,MYBL2,RUNX1)x2[200]. The patient relapsed with AML in September 2019 and underwent treatment. However, all AML treatment options were exhausted by March 2020. An isodicentric chromosome 7 leading to two copies of the short arm of chromosome 7 (7p) and deletion 7q is a rare event in AML and is rarely described in the literature. The key element here is that this specific rearrangement leads to deletion 7q which is a well-known abnormality in AML that places the patient in the Poor/Adverse risk category.