Radiation colitis

Radiation colitis is inflammation of the colon due to radiation. It is usually iatrogenic. This article also covers radiation proctitis.

General

• Diagnosis should be supported by the clinical history.

General DDx for a colitis:

• Idiopathic, e.g. inflammatory bowel disease.
• Infection.
• Ischemia.
• Radiation.

Gross

• Superficial bowel wall injury - shallow ulceration.
• Telangiectatic lesions.

Image:

• Telangiectatic lesions (nature.com).

Microscopic

Features - acute:

• Mucosal changes:
  • Necrosis of epithelium.
    • "Ghost cells" = cells without nuclei.
  • Hemorrhage.
• Submucosa edema with neutrophilic infiltrate.
• +/-Fibrin thrombi.

Features - chronic:

• Nuclear atypia - esp. of the stromal cells.
  • The epithelium is shed and regenerates... therefore usually does not have the changes.
• Fibrosis - esp. of the submucosa.

DDx:

• Ischemic colitis.
• Inflammatory bowel disease.
• Infectious colitis.

Images:

• Radiation colitis - rat model (bmj.com).
• Radiation colitis (nature.com).

See also

• Inflammatory bowel disease.
• Colon.
• Radiation changes.