the presence of an idic(ph ) chromosome(s ) represents a mechanism for genomic bcrabl1 amplification and may contribute to resistance against targeted therapies based on imatinib or dasatinib . a 52yearold , previously healthy man presented to his local ed with worsening right groin pain of 2months duration , which began after a traumatic fall with direct trauma to that site . at that time , he was discharged home from the ed with a diagnosis of rectus sheath hematoma . his pain continued to progress , and he returned to the ed where repeat ct demonstrated worsening hematoma size and a cbc showed significant leukocytosis . the patient was transferred to our hospital with a concern for leukemia . at our institution , the admission white blood cell count ( wbc ) was 116.4  10/l with a differential consisting of 70% neutrophils , 3% metamyelocytes , 6% myelocytes , 2% promyelocytes , 7% lymphocytes , 5% eosinophils , 4% basophils , and 3% blasts ( fig . the platelet count was 506  10/l and the hemoglobin level was 10.5 g / dl . ( a ) the peripheral blood smear shows a leukocytosis with neutrophils at various stages of maturation , a basophilia ( < 20% ) , and 3% blasts ; ( b ) the marrow is hypercellular with diffuse granulocytic proliferation and numerous  dwarf  megakaryocytes ; ( c ) bcrabl1 fish showed a variant fusion pattern ( 3 fusions ; 1 orange ; 1 green ) ; ( d ) chromosome analysis revealed an abnormal male karyotype with an isodicentric philadelphia chromosome ; ( e ) metaphase fish studies show the presence of two bcr / abl1 fusion signals on the idic(ph ) chromosome . peripheral blood flow cytometry showed an increased granulocyte population with leftshifted maturation and myeloblasts accounting for about 2.5% of the total events . a bone marrow biopsy showed findings consistent with cml including marked marrow hypercellularity with leftshifted granulocytic preponderance , numerous  dwarf  megakaryocytes , and 3% blasts ( fig . 1b ) . fluorescence hybridization ( fish ) analysis on the bone marrow with bcrabl1 dualcolor , dualfusion probes revealed three distinct bcr / abl1 fusion patterns . the typical bcr / abl1 fusion pattern was observed in 31% of interphase nuclei analyzed . a variant bcr / abl1 fusion pattern ( 3 fusions ; 1 orange ; 1 green ) 1c ) and 2.5% of nuclei showed 4 fusions ; 1 orange ; and 1 green pattern . karyotyping studies revealed the presence of an isodicentric philadelphia chromosome , 46,xy , der(9)t(9;22)(q34;q11.2),22,+ider(22)(q10)t(9;22)(q34;q11.2 ) , in all 20 analyzed metaphases ( fig . additional metaphase fish studies with bcr / abl1 probes showed the localization of two fusion signals on the isodicentric philadelphia chromosome and another fusion signal on the derivative chromosome 9 ( fig . bcrabl1 fusion transcripts were at the level of 100% on the international scale ( is ) . two weeks later , the wbc trended down to 40  10/l and ldh level was 299 the 3month followup visit showed complete hematological response , with the bone marrow showing morphologic remission and a normal karyotype ( 46,xy ) by unstimulated bone marrow culture . however , pcr studies for the mutant transcript showed that there was lack of a major molecular response ( mmr , defined as < 0.1% on the is ) with bcrabl1 transcripts at 6.12% on the is . the patient is clinically well and continues to be followed closely in the clinic at this time . chronic myeloid leukemia ( cml ) is linked to the philadelphia chromosome t(9;22)(q34;q11.2 ) , which results in the formation of a chimeric bcrabl1 gene fusion . by binding to the kinase domain of abl1 , imatinib mesylate inhibits the function of the fusion gene and is a highly effective therapy . . mechanisms of resistance against imatinib treatment may include mutations within the abl1 kinase domain , genomic bcrabl1 amplification and clonal evolution 1 . very few cases of cml with the presence of idic(ph ) chromosome(s ) have been reported in the literature . the idic(ph ) chromosome has generally been observed in accelerated phase or in blast phase of cml 2 , 3 . in other cases , idic(ph ) chromosome(s ) were observed as a secondary chromosomal abnormality in patients resistant to imatinib mesylate or dasatinib 1 , 4 , 5 , 6 . in our patient , the idic(ph ) chromosome was observed at diagnosis with 3% blasts , suggesting the presence of idic(ph ) in chronic phase . additional studies will help in clarifying the prognostic significance of the presence of idic(ph ) chromosome during the chronic phase of cml . to date , only one other study reported the occurrence of idic(ph ) chromosome during chronic phase cml , and this case was associated with lack of hematological and cytogenetic response despite administering higher doses of imatinib 7 .