Mycosis fungoides - A cutaneous lymphoproliferative disorder in a patient treated with fingolimod for multiple sclerosis.

Fingolimod was the first oral disease-modifying drug approved for the treatment of relapsing-remitting multiple sclerosis (MS). It has previously been associated with rare cases of lymphoma. Here we describe the first case of mycosis fungoides - a cutaneous lymphoproliferative disorder, in an MS patient treated with fingolimod. who developed histologically confirmed mycosis fungoides 3 years after starting fingolimod. The drug was withdrawn and the patient was treated with radiotherapy and surgical excision with remission. This report points to a possible association between fingolimod and skin lymphoproliferative disorder and emphasizes the need for periodic skin examination.