Mycosis fungoides, nitrogen mustard and skin cancer.

The prevalence of epithelial cancer was determined in 202 patients with mycosis fungoides and the Sézary syndrome and was found to be 10.5%. In an attempt to establish a possible association with topically applied nitrogen mustard, it was noted that 4.0% of these patients had lesions prior to nitrogen mustard therapy (although over half subsequently developed further lesions) and 6.5% of the patients developed them de novo after therapy. In two patients in this latter group, malignancies developed in are as not usually associated with solar-induced cancer. These findings indicate that epidermal neoplasia is not uncommon in these patients and that nitrogen mustard may function as a carcinogen or a co-carcinogen.