Psoriatic arthritis induced by anti-PD1 and treated with apremilast: a case report and review of the literature.

Immune checkpoint inhibitors targeting programmed cell death protein 1 pathways are generally well tolerated, but immune-related adverse events have been observed in more than 80% of all patients. Rheumatic and musculoskeletal immune related adverse events have to date not been widely recognized or well characterized. Psoriasic arthritis is a rare entity and it makes management of patients difficult due to the limited therapeutic possibilities and the strong impact on the quality of life. The majority of cases were treated with glucocorticoids, in some cases not enough. We present the case of a patient with psoriasic arthritis and report cases described in literature of patients treated with apremilast, a small oral molecule that inhibits of phosphodiestherase 4.