Cytokine release syndrome and immune effector cell‑associated neurotoxicity syndrome in a melanoma patient treated with adjuvant pembrolizumab.

The emergence of immune checkpoint inhibitors (ICIs) has significantly improved the prognosis of patients with solid tumors. However, along with their efficacy, new toxicities related to immune system activation have surfaced, some of which pose life-threatening risks. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are among the serious, albeit rare, immune-related adverse effects (irAEs) observed. Although commonly associated with hematologic malignancies and chimeric antigen receptor T cell therapies, CRS has been reported in patients treated with ICIs, with ICANS being a less documented complication. The present study presents a case report of a 76-year-old patient with resected melanoma who developed clinical symptoms of CRS and ICANS following adjuvant pembrolizumab therapy. The patient presented with neurological symptoms of weakness and encephalopathy with confusion, bradypsychia, dysarthria, tremors and visual hallucinations. Laboratory tests revealed elevated serum levels of tumor necrosis factor-alpha and interleukin-6 along with inflammatory markers, hepatic and renal dysfunction, as well as rapidly progressive normochromic-normocytic anemia. Treatment with corticosteroids led to rapid symptom resolution, albeit with subsequent symptom recurrence after tapering its dose. This case underscores the importance of recognizing and managing irAEs associated with ICIs and highlights the need for vigilant monitoring and individualized therapeutic approaches.