Preleukaemia (haemopoietic dysplasia) developing in a patient with psoriasis treated with 8-methoxypsoralen and ultraviolet light (PUVA treatment).

A 73-year-old man who had suffered for many years from psoriasis was treated with systemic psoralen and longwave ultraviolet light. After 1 year he developed a preleukaemic condition characterized by a refractory anaemia, a slight thrombocytopenia and a normo- to hypercellular bone marrow with an excess of myeloblasts. Karyotyping revealed an abnormal chromosome (12p-) and agar cultures of bone marrow showed moderate growth with a high cluster/colony ratio. He died 1 year later of renal failure precipitated by an acute pancreatitis. Owing to the possible causal relationship we would like to advise increased attention to the haematopoietic system of patients treated with psoralen.