An introduction to gastrointestinal pathology
Gastrointestinal pathology is a large part of pathology as radiologists can often describe the extent of disease... but don't get the diagnosis right all the time.
Normal
Layers of the alimentary canal:[1][2]
- Mucosa (epithelium, lamina propria, muscularis mucosa).
- Submuscosa and submucosal plexus (or Meissner's plexus).
- Muscularis externa (inner longitudinal, myenteric plexus (or Auerbach's plexus) outer circumferential).
- Adventitia (if retroperitoneal), serosa (if intraperitoneal).
Bowel
- Villi - should see three good ones in a normal biopsy.
- Crypts.
- Paneth cells.
- Small bowel (as above).
- Submucosal glands (Brunner's glands).
Large bowel vs. small bowel:
- Small intestine.
- Villi (key feature).
- Brunner's glands - duodenum only (key feature).
- Paneth cells more common.
- Paneth cells are in the base of the crypts and have eosinophilic granules. They are found (normally) in the small bowel and right colon. They may appear on the left side (i.e. descending colon) in pathologic states, e.g. IBD.
- Large intestine
- More goblet cells.
- More lymphocytes usually.
Luminal gastroenterology
Intestinal polyps
The bread and butter of gastrointestinal pathology.
Esophagus
Largely forgotten organ at SB... but no shortage of these at SMH.
Stomach
H. pylori, cancer and more...
Small bowel
The part of the GI tract that pathology has mostly forgot.
Duodenum
Commonly biopsied. Celiac... cancer... giardia?
Colon
Includes discussion of the rectum and IBD.
Appendix
Acute appendicitis and more...
Accessory GI
Gallbladder
A growth industry... with the expanding waist lines in the (Western) world.
Liver
An organ that pathologists now sometimes forget. There are separate articles for the medical liver diseases and liver neoplasms.
