OBJECTIVETo report on clinical and laboratory features of myeloid neoplasms with double del(20q).

METHODSCytogenetic examination of bone marrow was performed on 13 cases of myeloid neophasms with double del(20q) after 24 hours of cell culture. R-banding was used to analyze the karyotypes. Interphase fluorescence in situ hybridization (FISH) was performed using dual-color probes for 20q11/20q12.

RESULTSDouble del(20q) was found to be the sole abnormality in 9 cases, double del(20q) and trisomy 9 was found in 1 case, trisomy del(20q) was found in 1 case, and sole del(20q) clone and double del(20q) clone were found to coexist in 2 cases. In 10 cases, interphase FISH showed one green and one red signal in cells with del(20q), which indicated deletion of both 20q11 and 20q12. Immunophenotyping of the leukemia cells showed positiveness for CD13 and/or CD33, CD117 in all 9 cases. Among these, co-expression of CD34 and/or HLA-DR was found in 6 cases, and coexpression of CD3 and CD7 was found in 1 case. Of the 13 cases, there were one AML-M6, nine MDS, one pure amegalokaryocye aplastic thrombocytopenia, one with normal morphology of bone marrow, and one undetermined due to dilution of the bone marrow by blood. Cytopenia were found in all cases. 9 of 13 cases died, and 4 survived with a median survival of 9 months.

CONCLUSIONDouble del(20q) is a rare but recurrent chromosomal abnormality derived from del(20q). It has unique clinical and laboratory features, and the prognosis is poor.