Malignant melanoma during treatment with fumaric acid esters - coincidence or treatment-related?

Psoriasis is today generally considered a systemic disease. Systemic therapies are used frequently. In Germany fumaric acid esters - FAE (Fumaderm(®) ) - are employed in more than 50 % of the patients requiring such therapy. We report for the first time the development of melanoma in two patients during their treatment with FAE. The logical question is - are the tumors coincidental or might they be treatment-related? Further investigations of pathways and immunologic effects as well as careful reports of side effects are necessary to estimate the risks of malignancy of FAE.