Small-vessel vasculitis leading to severe acute kidney injury after ipilimumab: a case report.

Immune checkpoint inhibitors are effective monoclonal antibodies used in cancer treatment, particularly in metastatic melanoma. They target proteins responsible for cancer cells evading the immune system. However, their use can lead to immune-related adverse events, with the skin and gastrointestinal tract being commonly affected. Kidney involvement is rarer, with interstitial nephritis being the most common manifestation. In a unique case, kidney biopsy-proven small-vessel vasculitis with arteriolar immune deposition was observed following ipilimumab administration.