Abstract
BACKGROUND: Eosinophilia has been reported as a rare, new biological effect of immune checkpoint inhibition that may be associated with improved treatment response and the development of immune-related adverse events. CASE PRESENTATION: We report a case of dual checkpoint inhibitor-associated hypereosinophilia and eosinophilic enteritis in a patient with advanced cutaneous melanoma. Rapid resolution of peripheral eosinophilia and associated symptoms was achieved with steroids alone. CONCLUSIONS: Immune checkpoint inhibition can trigger inflammation in virtually any organ in the body, leading to diverse clinical manifestations. To our knowledge, this is the first case report of eosinophilic enteritis due to ipilimumab plus nivolumab.