Widespread cutaneous carcinomas associated with human papillomaviruses 5, 14 and 20 after introduction of methotrexate in two long-term PUVA-treated patients.

Background: PUVA treatment for patients with severe psoriasis has been demonstrated to be highly effective. However, an increased risk of nonmelanoma and melanoma skin cancers has been reported. It is generally accepted that the risk of squamous-cell carcinoma (SCC) is significantly increased in patients with long-term PUVA therapy.