Development of Seborrheic Keratosis and Human Papillomavirus (HPV) Infection Following Four Months of Fingolimod Treatment in a Patient With Multiple Sclerosis: A Report of a Rare Case.

Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system in young adults. Disease-modifying therapies (DMTs) for MS target different aspects of the immune system and have various safety profiles. Fingolimod is a DMT introduced for the treatment of MS. Cutaneous adverse events have been well described in patients treated with fingolimod. We present a clinical case of a patient with relapsing-remitting multiple sclerosis (RRMS) who developed multiple skin lesions after four months of treatment with fingolimod. Diagnosis of seborrheic keratosis, nevi, and papilloma was made clinically based on characteristic lesion morphology. Histologic confirmation was not performed, and human papillomavirus (HPV) DNA testing was positive. Rapid progression of cutaneous lesions prompted the switch to a different DMT, after which the lesions resolved completely within two months.