IDH1 and myeloid sarcoma: Integrative Genomics Viewer (IGV) visualization of next-generation sequencing (NGS) data revealed the consistent detection of the low-frequency somatic IDH1 p.Arg132Cys mutation between SCH tissue and cystic blood-derived cfDNA, supporting the hypothesis that cell-free DNA from plasma could be a promising alternative for tissue sample to promote molecular diagnosis of MS.