Dermatological Neoplastic Diseases Complicating Treatment with Monoclonal Antibodies for Multiple Sclerosis

Background: Over the past 20 years, the treatment scenario of multiple sclerosis (MS) has radically changed, and an ever-increasing number of disease-modifying treatments has emerged. Among high-efficacy treatment agents, monoclonal antibodies (mAbs) have become a mainstay in a MS patient’s treatment due to their targeted mechanism, high efficacy, and favorable risk profile. The latter varies from drug to drug and a skin cancer warning has emerged with sphingosine 1-phosphate receptor inhibitors. Several cases of skin malignancy in people with MS (pwMS) undergoing therapy with mAbs have also been described, but dermatological follow-up is not currently indicated. Objectives: The aim of this review is to investigate cases of cutaneous malignancy during mAb therapy and to explore possible pathophysiological mechanisms to evaluate the potential need for regular dermatological follow-ups in pwMS treated with mAbs. Methods: A literature search for original articles and reviews in PubMed was conducted with no date restrictions. Results: A total of 1019 results were retrieved. Duplicates were removed using Endnote and manually. Only peer-reviewed studies published in English were considered for inclusion. At the end of these screening procedures, 54 studies published between 2001 and 2024 that met the objectives of this review were selected and reported. Conclusions: The available data do not show a clear link between monoclonal antibody (mAb) treatment in pwMS and the risk of skin cancer. At present, these treatments remain contraindicated for people with cancer. Dermatological screening is advisable before starting mAb treatment in pwMS, and subsequent follow-ups should be individualized according to each patient’s risk profile.