The 4 cases with positive cytogenetic abnormalities all had concurrent bone marrow involvement at diagnosis of MS (Table 1): 1 case with t(8;21) (q22;q22) (case 18); 1 case with FLT3-ITD heterozygous mutation and del(22q11) (case 12); 1 case with t(9;22) (q34;q11), inv(17) (q10), and trisomy 8 (case 10); and 2 cases with t(9;22) (q34;q11). The gene discussed is FLT3; the disease is myeloid sarcoma.