Pyoderma gangrenosum in acute myeloid leukaemia during immunosuppression.

We describe a patient who developed pyoderma gangrenosum during the remission phase of acute myeloid leukaemia whilst receiving maintenance therapy with methotrexate and 6-mercaptopurine. The spontaneous resolution of these skin lesions following discontinuation of chemotherapy suggests that these drugs may be of major significance in the aetiology of pyoderma gangrenosum. Nevertheless, 27 months later, a relapse of the leukaemia followed. Although pyoderma gangrenosum occurred during clinical remission, we cannot rule out a synergism of leukaemia and chemotherapy in its pathogenesis.