Skin infiltration associated with chronic myelomonocytic leukaemia.

Chronic myelomonocytic leukaemia (CMML) is typically associated with a prolonged clinical course and is not usually very responsive to chemotherapeutic intervention. Skin infiltration has not been recognized previously as a feature of this illness. We have seen four patients recently with CMML, who during the the course of their illness developed marked skin infiltration. Whilst sensitivity to chemotherapy could be demonstrated in the peripheral blood cell population, skin infiltration was quite resistant to treatment. Skin infiltration heralded a more aggressive phase of the disease although no discernible change in morphology, cytochemistry or membrane marker analysis of the leukaemic cell population could be demonstrated in three of the patients studied; one patient, however, transformed to an acute leukaemia shortly thereafter.