Development of Subcutaneous Panniculitis-Like T-cell Lymphoma After Immune Checkpoint Inhibitor Treatment.

Program death 1 (PD-1) inhibitors such as nivolumab are immune checkpoint inhibitors that have revolutionized the treatment of metastatic melanoma. Despite its success in treating melanoma, immune activation can lead to immune-related adverse effects, which are experienced by half of melanoma patients treated with PD-1 inhibitors. Despite the common frequency of immune-mediated adverse events, the development of a secondary lymphoma is exceedingly rare. We present the case of a 53-year-old woman diagnosed with stage IV metastatic melanoma, treated with nivolumab, who subsequently developed fatal subcutaneous panniculitis-like T-cell lymphoma (SPTCL).