Specific cutaneous involvement in the course of chronic myelomonocytic leukemia simultaneously with blastic leukemic transformation. Report of a case with histologic and cytochemical study.

We report a case, in a 74-year-old man, of chronic myelomonocytic leukemia (CMML) that showed cutaneous involvement in its terminal phase. The patient developed a nodular eruption with an irregular distribution over the entire skin surface. Histology showed an acute leukemic infiltration in the reticular dermis. We were able to demonstrate cells with intermediate myeloid and monocytic characteristics ("paramyeloid cells") in the skin biopsy and in bone marrow smears. There have been only four patients reported previously with similar clinical findings. In one of them the cutaneous eruption heralded an aggressive clinical shift of the disease, as in our case. The present case confirms the utility of skin biopsy in similar cases for predicting the evolution of the disease.