Colon

• Inflammatory condition that affects colon distal to an ileostomy or colostomy
• It can also occur in sigmoid segments used in colovaginoplasty procedures

• Generally reported that no significant associations exist between diversion colitis and age of onset, gender, stoma type or mode of surgery (Int J Colorectal Dis 2017;32:1191)
  • However, Tominaga et al. reported a slight predominance in men (World J Gastroenterol 2018;24:1734)
• Greatest association with diversion colitis is simply the surgical interruption of the normal flow of fecal material through the bowel

• Clinical features are highly variable but presentation may include
  • Abdominal pain
  • Tenesmus
  • Anal and rectal pain
  • Mucous discharge
  • Rectal bleeding
  • Some patients may present with endoscopic or histologic findings but may remain asymptomatic
• When evaluating clinical features, it is important to contextualize those signs and symptoms within the appropriate setting; for instance, the above features should raise suspicion for diversion colitis in patients with ileostomies, with some research to suggest that symptoms can arise from months to years after ileostomy construction (World J Gastroenterol 2018;24:1734)

Images hosted on other servers:

• 12 year old girl with myelomeningocoele with fecal incontinence managed with colostomy construction and subsequent resection of distal defunctionalized bowel (Histopathology 1994;24:395)
• 19 year old woman with Berdon syndome (megacystis microcolon intestinal hypoperistalsis syndrome [MMIHS]) diagnosed with diversion colitis after ileostomy construction (Dig Dis Sci 2009;54:2338)
• 42 year old woman with androgen insensitivity syndrome with diversion colitis of sigmoid neovagina (Frontline Gastroenterol 2016;7:227)
• 51 year old woman with Crohn's disease and microcarcinoids in association with diversion colitis symptoms presenting more than 17 years after subtotal colectomy and ileostomy (J Crohns Colitis 2008;2:246)

Contributed by Catherine E. Hagen, M.D. and Dustin W. Parsons, M.D.

• Inflammatory bowel disease (IBD) (ulcerative colitis or Crohn's disease):
  • Histologic distinction can be challenging and diversion colitis can co-occur with IBD
  • More severe inflammatory changes may indicate superimposed IBD (Hum Pathol 2022;123:31)
• Segmental colitis associated with diverticulosis (SCAD):
  • Occurs in segment of colon with diverticula and rectum is typically spared
• Radiation colitis:
  • Occurs in patients with history of radiation therapy for malignancy (e.g., of prostate, colon, bladder)
  • Acute radiation may demonstrate a number of histologic findings, including nuclear atypia, reduction in mitotic counts, eosinophilic inflammation (including eosinophilic cryptitis and crypt abscess formation), goblet cell derangements and fibroblastic proliferation
  • Chronic exposure may result in Paneth cell metaplasia, architectural distortion, fibrosis of lamina propria, chronic inflammation, hyalinized vasculature, vascular ectasia and thrombosis

A 5 month old infant is seen in the emergency department with bloody bowel movements. She appears uncomfortable and begins crying with abdominal palpation. She is afebrile and her white blood cell count is within normal limits. Medical history is significant for premature birth complicated by necrotizing enterocolitis with bowel resection and ileostomy construction. A biopsy of the colonic stump is likely to demonstrate which of the following findings?

1. Crypt abscesses, Paneth cell metaplasia, marked architectural distortion, basal lymphoplasmacytosis
2. Endothelial cells demonstrating owl eye intranuclear inclusions with associated clear halo
3. Intraepithelial lymphocytosis
4. Prominent lymphoid hyperplasia, muscularis mucosa hypertrophy and crypt abscesses

D. Prominent lymphoid hyperplasia, muscularis mucosa hypertrophy and crypt abscesses. These findings are characteristic of diversion colitis. The patient’s history of bowel resection with ileostomy should raise suspicion for diversion colitis. Answer A is incorrect because these findings are more demonstrative of ulcerative colitis. It can be difficult to separate out the 2 conditions and reports in the literature exist of concomitant ulcerative colitis and diversion colitis. With overlapping symptoms and the potential for finding crypt abscesses in both conditions, it can certainly pose a diagnostic challenge for pathologists trying to differentiate the 2 conditions on biopsy. The patient’s history of ileostomy construction should be a clue that diversion colitis may be favored here. Without a pre-existing diagnosis of inflammatory bowel disease (IBD), this is unlikely. Answer B is incorrect because the characteristic owl eye inclusions are consistent with cytomegalovirus (CMV) colitis. This consideration of this condition may be greater in patients with a history of immunosuppresion; for instance, in patients with human immunodeficiency virus (HIV) or those receiving immunosuppressive therapy following solid organ transplant. Answer C is incorrect because intraepithelial lymphocytosis is characteristic of lymphocytic colitis, which typically presents with watery, nonbloody diarrhea. Microscopic colitis is uncommon in the pediatric population.

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Reference: Diversion colitis

A 72 year old man with a history of colon cancer undergoes radiation therapy, followed by partial colon resection with construction of an ileostomy. He denies any history of inflammatory bowel disease. The image shown above demonstrates histologic findings of the resected portion of the colon. These findings are most consistent with which clinical presentation?

1. Diversion colitis
2. Infectious agent
3. Radiation colitis
4. Ulcerative colitis

A. Diversion colitis. The construction of an ileostomy should always raise suspicion for the possibility of diversion colitis. The prominent lymphoid aggregates are likely the most characteristic finding associated with diversion colitis. Other features appreciated here include patchy hypertrophy of muscularis mucosa, ulceration and loss of colonic crypts. Answer B is incorrect because the clinical vignette does not suggest any fevers or bowel symptoms consistent with an infectious etiology. Infectious colitis typically shows a histologic pattern of acute self limited colitis without architectural distortion. Answer C is incorrect because the presence of lymphoid aggregates should favor diversion colitis over radiation colitis. Radiation colitis is typically pauci-inflammatory with evidence of lamina propria fibrosis and hyalinized ectatic vessels. Answer D is incorrect because while diversion colitis can have overlapping histologic features with inflammatory bowel disease, given that the patient denies any history of underlying inflammatory bowel disease, this is unlikely to be a manifestation of ulcerative colitis.

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Reference: Diversion colitis