[Transient monocytic skin infiltrate during preleukemic phase of acute myelomonocytic leukemia]

An acute myelomonocytic leukemia presenting transient skin rash during preleukemic phase was described. Following four years of unexplained leukopenia, a generalized exanthema developed and subsequently regressed spontaneously. The skin biopsy and immunohistochemistry revealed monocytic infiltration into the dermis. Twenty-eight months later, the patient became leukemic and died. The skin lesions, however, did not occur after leukemic transformation. Probably transient monocytic skin infiltrate was a symptom of preleukemia, a stem cell neoplasm manifested by functionally abnormal maturation.