tion. However, epistaxis and dyspnea appeared suddenly 2 months later. She exhibited 27% abnormal cells of WBC (7300/lL) and up to 94% of bone marrow cells. When she was diagnosed with acute monoblastic leukemia (FAB M5a) in AML, she had already developed disseminated intravascular coagulation, renal failure and pneumonia. In the following 2 days, she died of exacerbation of dyspnea and renal failure.Although it remains unclear whether aleukemic CMS originates in the skin or is cutaneous colonization of blast cells from the bone marrow, the latter is likely to be the case, because the subpopulation of malignant myeloid clones can express the homing receptor to specifically infiltrate into the skin through interaction with chemokines. 4 Like our case, a previous study reported two cases of AML, which were preceded by CMS with spontaneous remission. 5 We did not perform an immediate diagnosis of leukemia because of very late appearance of leukemic cells in the bone marrow or peripheral blood, in addition to spontaneous resolution of skin lesions. Because aleukemic CMS is a disease with heterogeneous clinical and pathological manifestations with undefined pathogenesis, our case implies that aleukemic CMS should be rendered as an AML-related condition and treated, even if skin lesions spontaneously disappear.