In Search of a Histopathological Pattern of Immune-Mediated Gastritis from Nivolumab Therapy: A Case Report with Literature Review

Abstract
Immunotherapy with checkpoint inhibitors is associated with termed inflammatory and immune-related side effects (irAE). Upper gastrointestinal symptoms are infrequent and appear mainly in patients on combination therapy with two checkpoint inhibitor drugs. We present the case of a patient with IIIB stage cutaneous melanoma treated with Nivolumab in monotherapy who developed an immune-mediated gastritis. Histopathologically, due to the paucity of published cases, no specific pattern of Nivolumab-immune-mediated gastritis has been described. We have reviewed the literature and compared the histopathology of the cases available in the literature.