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
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).
Cell types
- Goblet cells.
- Secrete mucin.
- Enterochromaffin cells, AKA Kulchitsky cells.
- Subnuclear eosinophilic granules.
- Serotonin.
- Subnuclear eosinophilic granules.
- Paneth cells.
- Supranuclear eosinophilic granules.
Memory device:
- Supranuclear granules = paneth cell.
Bowel
Small bowel
- Villi - should see three good ones in a normal biopsy.
- Crypts.
- Paneth cells.
- Goblet cells.
- Few in proximal small bowel (duodenum).
- Abundant in distal small bowel (ileum).
Duodenum
- 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
Non-regional
Intestinal polyps
The bread and butter of gastrointestinal pathology.
Regional
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. Crohn's disease is dealt with in a separate article.
Duodenum
Commonly biopsied. Celiac... cancer... giardia?
Colon
Colorectal tumours are dealt with in colorectal tumours. Crohn's disease and ulcerative colitis are dealt with in the inflammatory bowel disease article. Includes discussion of the rectum. The anus is a separate article.
Appendix
Acute appendicitis and more...
Accessory organs of the gastrointestinal tract
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, liver neoplasms and liver transplantation pathology.
Pancreas
An organ that is occasionally afflicted by cancer. It is primarily seen in large centers where they do ERCPs and Whipples.
Pathology (detail articles)
Inflammatory bowel disease
The bread and butter of gastroenterology and GI pathology.
Gastrointestinal stromal tumour
The most common GI stromal tumour.
Graft-versus-host disease
An uncommon thing that complicates bone marrow transplants.
Eosinophilic enterocolitis
- For the esophageal disease see: Eosinophilic esophagitis.
General
- Uncommon.
- Associated with food allergies, esp. in children.[3]
Microscopic
Features:
- Eosinophilia.
- Eosinophilic abscesses.
DDx:
- IBD.
- Infection.
- Drug reaction.
Pneumatosis intestinalis
General
- Bad prognosis - esp. if diffuse.
Gross
- Small bubbles in the intestinal wall.
Microscope
Features:
- Large submucosal pseudocysts.
Image:
Pneumatosis cystoides intestinalis
General
- Benign, generally asymptomatic subset of pneumatosis intestinalis.[5]
- Small or large bowel.[6]
Etiology - many, e.g. IBD, infection.
Gross
- Polypoid lesions.
Image: Pneumatosis cystoides intestinalis (colmed5.org.ar).
Microscopic
Features:
- Large submucosal pseudocysts lined by macrophages and multi-nucleated giant cells.
Image:
See also
References
- ↑ URL: http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Oral/Oral.htm.
- ↑ URL: http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Oral/Images/gitplan.gif.
- ↑ Lucendo AJ (September 2010). "Eosinophilic diseases of the gastrointestinal tract". Scand. J. Gastroenterol. 45 (9): 1013–21. doi:10.3109/00365521003690251. PMID 20509820.
- ↑ 4.0 4.1 Takami, Y.; Koh, T.; Nishio, M.; Nakagawa, N. (2011). "Pneumatosis intestinalis leading to perioperative hypovolemic shock: Case report.". World J Emerg Surg 6: 15. doi:10.1186/1749-7922-6-15. PMC PMC3108289. PMID 21548980. https://www.ncbi.nlm.nih.gov/pmc/articles/PMCPMC3108289/.
- ↑ URL: http://emedicine.medscape.com/article/371955-overview. Accessed on: 24 January 2012.
- ↑ Micklefield, GH.; Kuntz, HD.; May, B.. "Pneumatosis cystoides intestinalis: case reports and review of the literature.". Mater Med Pol 22 (2): 70-2. PMID 2102980.
