The chilblain-like eruption as a diagnostic clue to the blast crisis of chronic myelocytic leukemia.

A 70-year-old Japanese man visited our clinic with the chief complaint of chilblain-like eruptions on the toes of both feet. His toes were bluish, erythematous, and swollen. Neither oral administration of vitamin E for 2 weeks nor wearing insulated socks improved the clinical manifestations. Peripheral blood examination revealed the presence of a large number of monocytic atypical cells and myeloblasts, anemia, and thrombocytopenia. In the bone marrow, monocytic cells were elevated, and myelocytic atypical cells were observed. Chromosomal analysis demonstrated Philadelphia chromosome. We diagnosed him as having a blast crisis of chronic myelocytic leukemia (CML). A biopsy specimen of the skin from the chilblain-like eruption showed infiltration of large, atypical, mononuclear cells; most of them were positive for CD68, and some of them were positive for CD14. Therefore, we concluded that the chilblain-like eruptions on his toes were specific skin lesions of a blast crisis in CML.