Colon
Muscular disorders
Brown bowel syndrome
Editorial Board Member: Danielle Hutchings, M.D.
Deputy Editor-in-Chief: Aaron R. Huber, D.O.
Last author update: 4 November 2024
Last staff update: 4 November 2024
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PubMed Search: Brown bowel syndrome
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Laboratory | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Electron microscopy description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Elgenaid SN, Alkurdi A, Ali W. Brown bowel syndrome. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colonbrownbowel.html. Accessed December 4th, 2024.
Definition / general
- Rare condition associated with longstanding malabsorption
- Gastrointestinal tract dysmotility due to free radical oxidative stress and pseudo-obstruction
- Reference: Case Rep Gastroenterol 2021;15:960
Essential features
- Most commonly occurs secondary to chronic malabsorption in elderly
- Accumulation of lipofuscin granules within the smooth muscle of bowel wall due to free radical oxidative stress
- Associated with low vitamin E levels and clinically the symptoms may improve with vitamin E treatment (Mayo Clin Proc 1979;54:752)
- Reference: Case Rep Gastroenterol 2021;15:960
Terminology
- Brown bowel syndrome (BBS)
- Intestinal lipofuscinosis
Epidemiology
- Affects older patients, with a mean age of 58 years old (Am J Surg Pathol 2020;44:834)
Sites
- Small intestine is most commonly affected
- May affect large intestine, esophagus, stomach and very rarely, extragastrointestinal sites (N Am J Med Sci 2013;5:669, Am J Surg Pathol 2020;44:834)
Pathophysiology
- Chronic malabsorption leads to vitamin E deficiency and subsequently diminished antioxidant effect
- Free radical damage of lipid containing membranes of the mitochondria that results in production and accumulation of lipofuscin granules within smooth muscles of gastrointestinal tract (brown color)
- Results in myopathy and dysmotility (pseudo-obstruction), which aggravates the underlying disease
- References: Case Rep Gastroenterol 2021;15:960, J Surg Case Rep 2018;2018:rjy039, Case Rep Surg 2019;2019:4706592
Etiology
- Vitamin E deficiency due to malabsorption
- Associated with celiac, chronic pancreatitis, liver disease, alcoholism
- Inflammatory bowel disease (Arch Pathol Lab Med 1980;104:201)
- Jejunoileal bypass surgery (Case Rep Gastroenterol 2021;15:960)
- Rarely occurs concomitant with gastrointestinal adenocarcinoma (Am J Gastroenterol 1994;89:812)
- References: Digestion 2014;89:105, Case Rep Surg 2019;2019:4706592
Clinical features
- Abdominal pain
- Weight loss
- Vomiting
- Diarrhea and steatorrhea
- Pseudo-obstruction of the bowel
- Symptoms of malabsorption and vitamin and protein deficiency
- References: Digestion 2014;89:105, Am J Surg Pathol 2020;44:834
Diagnosis
- Clinical, laboratory and imaging
- Small / large bowel biopsy or bowel resection
Laboratory
- Diagnosis of malabsorption (C reactive protein [CRP], albumin, total protein, fat content in stool, etc.)
- Serum levels of vitamin E
- Reference: Digestion 2014;89:105
Radiology description
- Abdominal Xray and magnetic resonance imaging (MRI) / computed tomography (CT): ileus with distended small and large bowel (Case Rep Gastroenterol 2021;15:960)
Radiology images
Images hosted on other servers:
Xray: significantly dilated small and large bowel
Prognostic factors
- Some cases responded to vitamin E treatment (Digestion 2014;89:105)
Case reports
- 11 year old boy with recurrent diarrhea and partial intestinal obstruction (Pol J Pathol 2013;64:228)
- 61 year old man with brown bowel syndrome in a setting of recurrent bowel obstruction (SAGE Open Med Case Rep 2020;8:2050313X20945531)
- 64 year old woman with brown bowel syndrome in a setting of longstanding malabsorption (Case Rep Gastroenterol 2021;15:960)
- 79 year old man with brown bowel syndrome in an unusual case of sigmoid volvulus (J Surg Case Rep 2018;2018:rjy039)
- 8 cases of brown bowel syndrome in a multi-institutional case series (Am J Surg Pathol 2020;44:834)
Treatment
- Supportive treatment and vitamin E supplementation may improve the symptoms (Mayo Clin Proc 1979;54:752)
Clinical images
Images hosted on other servers:
Orange-brown specimen
Gross description
- Brown or orange-brown discoloration of the muscularis propria
Microscopic (histologic) description
- Lipofuscin accumulation (finely granular, brown pigment) in the cytoplasm of smooth muscle of the muscularis propria (Am J Surg Pathol 2020;44:834)
- Pigment may also be seen in smooth muscle of intermediate sized arteries in submucosa (Am J Surg Pathol 2020;44:834)
- Can be present in muscularis mucosae (Arch Pathol Lab Med 1990;114:76)
Microscopic (histologic) images
Contributed by Danielle Hutchings, M.D.
Pigmented macrophages in muscularis propria
Macrophages with lipofuscin accumulation
Pigmented macrophages in submucosal artery
Positive stains
- PAS and PASD
- Fontana-Masson
- Carbol lipofuscin
- Reference: Am J Surg Pathol 2020;44:834
Electron microscopy description
- Accumulation of lipofuscin pigment within the cytoplasm of smooth muscle cells
Sample pathology report
- Colon, resection:
- Segment of colon with colonic mucosa with lipofuscin deposition in the muscularis propria, consistent with brown bowel syndrome
Differential diagnosis
- Melanosis coli:
- Grossly may show brown pigmentation of mucosa, whereas the muscularis propria lacks pigmentation
- Pigment accumulation is within the macrophages in the lamina propria rather than within cytoplasm of smooth muscle cells
- Whipple disease:
- Expansion of lamina propria by foamy macrophages, which lack brown pigmentation
- Both may show PAS positive cytoplasmic granules; however, in Whipple disease, these are present in lamina propria macrophages rather than smooth muscle cells
Board review style question #1
This finding of periodic acid-Schiff (PAS) positive lipofuscin granules within the smooth muscle of the muscularis propria of the colon is typically seen in which of the following?
- Brown bowel syndrome
- Hemochromatosis
- Melanosis coli
- Whipple disease
Board review style answer #1
A. Brown bowel syndrome. The deposition of lipofuscin granules in the muscularis propria is characteristic of brown bowel syndrome. Answer C is incorrect because there is a diffuse deposition of melanized ceroid in the macrophages of lamina propria with melanosis coli. Answer D is incorrect because the lamina propria should be expanded by PAS positive foamy macrophages in Whipple disease. Answer B is incorrect because iron pigment should be seen in the epithelial cells in hemochromatosis and would be negative on PAS staining.
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Reference: Brown bowel disease
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Reference: Brown bowel disease
