Histopathologic Features of Unmasked Inflammatory Bowel Disease Following Immune Checkpoint Inhibitor Therapy in Colon Biopsies.

Background And Aims: Typical immune checkpoint inhibitor-induced colitis (T-ICI) has significant histomorphologic overlap with inflammatory bowel disease (IBD), a distinction further complicated in ICI-treated patients with pre-existing inflammatory bowel disease (P-IBD) and those with potentially "unmasked" inflammatory bowel disease (U-IBD) after ICI therapy. This study describes histopathologic findings seen in U-IBD colonic biopsies and assesses for distinguishing features from T-ICI and P-IBD biopsies.

Methods: Initial colon biopsies after symptom onset from 34 patients on ICI therapy were reviewed, and histopathologic features were tabulated.

The Development of Persistent Gastrointestinal Symptoms in Patients With Melanoma Who Have Had an Immune Checkpoint Inhibitor-Related Gastrointestinal Toxicity.

Introduction: Immune-related adverse events (irAE) secondary to immune checkpoint inhibitors (ICI) have gastrointestinal (GI) manifestations, including gastritis, enteritis, and/or colitis. The long-term sequelae of ICI-associated GI toxicities (GI-irAE), particularly the development of disorders of gut-brain interaction, are not well known. We characterized the incidence of persistent GI symptoms after GI-irAE.