Endoscopic evaluation of immunotherapy-induced gastrointestinal toxicity

Table 1 Differential diagnosis

Disease	Endoscopy findings	Clinical characteristics
IBD	UC: Continuous and circumferential mucosal inflammation starting in the rectum	Rectal bleeding, abdominal pain, diarrhea, chronic anemia
	CD: Deep fissures, cobblestoning, segmental distribution, relative rectal sparing, and terminal ileal involvement
Radiation colitis	Similar to IBD	Rectal bleeding, chronic anemia
Infectious colitis	Diffuse effects on the colon	Dysentery-like diarrhea, different agents, Clostridium difficile and CMV to be ruled out
Colitis associated with diverticulosis	Segmental distribution, peridiverticular, sigmoid colon affected, rectum and proximal colon are normal	Rectal bleeding, abdominal pain, diarrhea
NSAID-induced colitis	Any part of the intestine, isolated lesions	Recurrent abdominal pain, obstruction, perforation, hemorrhage, chronic anemia
Microscopic colitis	Normal endoscopy findings	Watery diarrhea
Ischemic colitis	Segmentary colitis (sigmoid /left colitis)	Acute onset of abdominal pain and rectal bleeding

IBD: Inflammatory bowel disease; UC: Ulcerative colitis; CD: Crohn’s disease; CMV: Cytomegalovirus; NSAID: Nonsteroidal anti-inflammatory drug.