RESUMO
<p><b>OBJECTIVE</b>To investigate the clinical significance of a rare chromosome abnormality der(Y)t(Y;1) in a patient with multiple myeloma (MM).</p><p><b>METHODS</b>The chromosome spread was prepared after 24 h culture of bone marrow. G-banding technique was used to analyze the karyotype. Fluorescence in situ hybridization (FISH) was performed to ascertain the origin of abnormal chromosome detected by conventional karyotypic analysis. Flow cytometry was used to detect the expression of the CD38/CD138/ZAP70. Immunoelectrophore was applied to identify the type of immunoglobulin.</p><p><b>RESULTS</b>A complex pattern of chromosome rearrangement was observed: 92,XXYY[3]/49,X,der(Y)t(Y;1)(q12;q21),t(11;14)(q13;q32),+18,+20,+21[47]/49,X,idem,del(13q22),ace[1]/98,XX,der(Y)t(Y;1) x 2,+18,+18,+20,+20,+21,+21[10]/46,XY[19]. The result was confirmed by metaphase-FISH. The type of immunoglobulin was IgD with the level of 6.24g/L. The CD38/CD138 was positive but ZAP70 was negative.</p><p><b>CONCLUSION</b>Structural abnormality of chromosome Y is rare in blood malignancy. Most of them were described in myelodysplastic syndrome or myeloproliferative disorders. It is the first report of der(Y)t(Y;1) abnormality in multiple myeloma.</p>