Eruptive epidermal cysts and multiple squamous cell carcinomas after therapy for cutaneous T-cell lymphoma.

Both topical nitrogen mustard and psoralen photochemotherapy may induce benign and malignant alterations in the skin. We describe the explosive appearance of multiple epidermal cysts and squamous cell carcinomas in a patient whose cutaneous T-cell lymphoma was treated sequentially with these two types of therapy. This is the first report of both processes in the same patient with cutaneous T-cell lymphoma. It strongly supports the concept of lesion induction, while raising the question of an additive or even synergistic effect of these types of therapy.