Fluorescence In Situ Hybridization Identifies Inversion 16 Masked by t(10;16)(q24;q22), t(7;16)(q21;q22), and t(2;16)(q37;q22) in Three Cases of AML-M4Eo

Bone marrow or peripheral blood from three patients had a t(10;16)(q24;q22), t(7;16)(q21;p13.1), and t(2;16)q37;q22), respectively. In all cases, fluorescence in situ hybridization confirmed an inv(16) masked by the translocation. The three patients were diagnosed with acute myelomonocytic leukemia and increased eosinophils. Because inv(16) has a favorable prognosis, identification of masked inv(16) will promote improved management of these cases. Therefore, all cases that have atypical rearrangement of chromosome 16 should be investigated for a possible inversion.