Epithelioid myxofibrosarcoma developing at the injection site of Adalimumab therapy for psoriatic synovitis.

The interplay between inflammation and cancer is the subject of intense interest. The recent approval of a number of checkpoint inhibitors has opened novel therapeutic pathways for several cancers. Conversely, biologic suppressors of inflammation, such as Tumor Necrosis Factor (TNF) inhibitors, have been utilized over the past two decades for the management of chronic inflammatory autoimmune diseases. While the overall rates of malignancy in patients using anti TNF therapies are not elevated, increased risk has been established for cutaneous malignancy, particularly carcinoma. In subsets of patients, such as those with rheumatoid arthritis, a modestly increased incidence of melanoma is also documented. Herewith, we present the first reported instance of a sarcoma of the dermis and superficial subcutaneous tissue at the injection site of Adalimumab in a woman being treated for psoriatic synovitis. We review the literature and suggest that a more nuanced documentation of adverse events is needed to clarify the iatrogenic risk of rare cancers, such as soft tissue sarcomas, in patients taking these biological therapies.