Remitting Seronegative Symmetrical Synovitis with Pitting Edema: A Case Report of an Immune-Related Adverse Event following Surgery.

Immune checkpoint inhibitors (ICIs) have emerged as a novel class of anti-neoplastic agent in oncology. Their integration into practice has been accompanied by "immune-related adverse events" (irAEs) wherein off-target immune responses damage healthy tissues. Severe irAEs can cause irreversible organ dysfunction and death. Despite this, little is known about factors which predispose certain patients to develop irAEs or which precipitate their onset. Here, we report a case of a patient with melanoma who completed adjuvant immunotherapy, underwent elective hip replacement, and developed a rare rheumatologic irAE (remitting seronegative symmetrical synovitis with pitting edema) post-operatively. Mechanistically, we hypothesize that surgery contributed to irAE pathogenesis as a sensitizing event in which self-antigens were presented to an immune system with diminished peripheral tolerance in the context of recent ICI administration. This case highlights a need for future correlative analyses, investigating whether iatrogenic interventions such as surgery might be associated with irAE development.