We also review all published literature on HCL with BCR/ABL1 rearrangement and discuss the pathophysiology of these unusual cases.     ///    De novo hairy cell leukemia with a major BCR/ABL1 rearrangement: a case report with a literature review..     ///    "After a thorough analysis of previous studies and the results of this patient, we speculate that a subclone evolved to have an additional genetic BCR/ABL1 rearrangement. "    ///    "Here we report a case of HCL expressing a BCR/ABL1 clone, which showed molecular remission of the fusion clones and achieved partial remission over nine months of cladribine therapy. "