Development of acute myeloid leukaemia in a patient with psoriasis treated with oral 8-methoxypsoralen and longwave ultraviolet light.

Acute myeloid leukaemia developed in a patient with psoriasis treated with oral 8-methoxypsoralen and longwave ultraviolet light (PUVA) 2 years earlier. Attention is called to the possibility that the effect of PUVA on DNA synthesis may not be limited to the areas of the skin being treated but - through damage to circulating multipotential stem cells - may also lead to haematological malignancies.