Endoscopic insights into digestive-related adverse effects of immune checkpoint inhibitors: A narrative review

Table 3 Histopathological characteristics of inflammatory patterns in biopsies from patients with immune checkpoint inhibitor-associated colitis

Histopathological pattern	Histopathological features
Active inflammation	Neutrophil epithelial infiltration, cryptitis, crypt abscess formation, with or without mixed-cell infiltration of the lamina propria
Chronic active inflammation	Basal lymphoplasmacytosis, crypt architectural distortion, paneth cell metaplasia, cryptitis and/or crypt abscess formation
Microscopic colitis	Lymphocytic type with lymphocytic epithelial infiltration, lymphoplasmacytic lamina propria expansion or collagenous type with thickened subepithelial collagen layer
Mixed type	Combined features from the aforementioned categories