Multiple squamous cell carcinomas in a patient with mycosis fungoides

SUMMARY A 51‐year‐old man with type IV skin presented for evaluation of a generalized rash associated with multiple ulcerated, nodular lesions on his legs. The nodular lesions occurred approximately 18 months after the initial onset of generalized rash, which had been diagnosed as plaque/patch stage mycosis fungoides. He continued to develop further nodular lesions on his trunk in the weeks following presentation. The nodular lesions were shown to be squamous‐cell carcinoma on histopathology. He had received only topical hydrocortisone prior to the development of the second cutaneous malignancy and had no past exposure to carcinogens. His squamous cell carcinomas were treated with surgical excision and split‐skin grafting. He received total skin electron‐beam therapy to treat the mycosis fungoides. Second malignancy in mycosis fungoides is a recognized phenomenon and usually occurs after potentially carcinogenic therapy. This case demonstrates the occurrence of second malignancy in the absence of a precipitating factor, suggesting that there are innate, immune‐mediated mechanisms in the development of cancer in patients with mycosis fungoides.