Villous adenoma: Difference between revisions
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{{CMG}}; {{AE}} {{MV | {{CMG}}; {{AE}} {{MV}} | ||
{{SK}} Adenomatous polyps; VA; TVA | {{SK}} Adenomatous polyps; VA; TVA | ||
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==Overview== | ==Overview== | ||
'''Villous adenoma''' (also known as adenomatous polyp) is a type of [[polyp (medicine)|polyp]] that grows in the [[gastrointestinal tract]] | '''Villous adenoma''' (also known as adenomatous polyp) is a type of [[polyp (medicine)|polyp]] that grows in the [[gastrointestinal tract]]; it occurs most commonly in the [[colon]]. Villous adenoma may result in [[malignant]] ([[cancerous]]) transformation.<ref>[http://www.cancer.gov/Templates/db_alpha.aspx?CdrID=44809 Villous adenoma]</ref> Villous adenoma was first discovered by Helwig in 1946.<ref name=":0">Helwig E.B. Adenoma of the large bowel in children. . American Journal of Diseases in Children. 1946;72:289–95</ref> According to the World Health Organization, villous adenoma may be classified into tubular, tubulovillous, and villous (most common) subtypes. Villous adenoma arises from epithelial tissue, which is normally part of the lining of the colon. The estimated risk of malignant transformation among villous adenomas is between 15% and 25%. Genes associated with the development of villous adenoma include [[APC]], [[TP53]], [[KRAS|K-ras]], and BAT-26. The [[prevalence]] of villous adenoma is approximately 3.5 per 100,000 individuals worldwide. The most potent risk factors in the development of villous adenoma include familial syndromes such as [[Turcot syndrome|Turcot syndrome]], [[Juvenile polyposis syndrome|juvenile polyposis syndrome]], and [[Cowden disease]]). Surgical removal is the mainstay of therapy for villous adenoma. Exploratory colonoscopy and cautery snare is the most common approach to the diagnosis and treatment of villous adenoma. Effective measures for the primary prevention of villous adenoma include periodic screening of patients with family history of [[familial adenomatous polyposis]]. Secondary prevention strategies include annual [[occult blood test]] and colonoscopy every ten years for patients above the age of 50. | ||
==Historical Perspective== | ==Historical Perspective== | ||
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==Classification== | ==Classification== | ||
Villous adenoma may be classified according to | Villous adenoma may be classified into 3 subtypes according to appearance:<ref name="pmid19764676">{{cite journal |vauthors=Osifo OD, Akhiwu W, Efobi CA |title=Small intestinal tubulovillous adenoma--case report and literature review |journal=Niger J Clin Pract |volume=12 |issue=2 |pages=205–7 |year=2009 |pmid=19764676 |doi= |url=}}</ref> | ||
*Tubular | *Tubular | ||
*Tubulovillous | *Tubulovillous | ||
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=== Symptoms === | === Symptoms === | ||
Villous adenoma is | Villous adenoma is commonly asymptomatic. Villous adenoma symptoms are often non-specific. Symptoms of villous adenoma may include: | ||
*[[Flatulence]] | *[[Flatulence]] | ||
*[[Abdominal pain]] | *[[Abdominal pain]] | ||
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*[[Diarrhea]] | *[[Diarrhea]] | ||
*[[Cramping]] | *[[Cramping]] | ||
*Pencil-thin stools | |||
=== Physical Examination === | === Physical Examination === | ||
Patients with villous adenoma commonly appear well. Physical examination findings are often non-specific. Physical examination may demonstrate: | Patients with villous adenoma commonly appear well. Physical examination findings are often non-specific. Physical examination may demonstrate: | ||
* | *Bright red blood on digital rectal examination | ||
*Rectal mass | *Rectal mass | ||
=== Laboratory Findings === | === Laboratory Findings === | ||
There are no specific laboratory findings associated with villous adenoma. In some cases, patients with villous adenoma may demonstrate positive fecal occult blood test or [[hypokalemia]].<ref name="wiki"> Villous adenoma. Wikipedia. https://en.wikipedia.org/wiki/Villous_adenoma Accessed on May 3, 2016 </ref> | There are no specific laboratory findings associated with villous adenoma. In some cases, patients with villous adenoma may demonstrate positive fecal [[occult blood test]] or [[hypokalemia]].<ref name="wiki"> Villous adenoma. Wikipedia. https://en.wikipedia.org/wiki/Villous_adenoma Accessed on May 3, 2016 </ref> | ||
=== | ===Other diagnostic studies=== | ||
[[Colonoscopy]] is the diagnostic modality of choice for villous adenoma. On [[colonoscopy]], characteristic findings of villous adenoma include:<ref name="pmid19764676">{{cite journal |vauthors=Osifo OD, Akhiwu W, Efobi CA |title=Small intestinal tubulovillous adenoma--case report and literature review |journal=Niger J Clin Pract |volume=12 |issue=2 |pages=205–7 |year=2009 |pmid=19764676 |doi= |url=}}</ref> | [[Colonoscopy]] is the diagnostic modality of choice for villous adenoma. On [[colonoscopy]], characteristic findings of villous adenoma include:<ref name="pmid19764676">{{cite journal |vauthors=Osifo OD, Akhiwu W, Efobi CA |title=Small intestinal tubulovillous adenoma--case report and literature review |journal=Niger J Clin Pract |volume=12 |issue=2 |pages=205–7 |year=2009 |pmid=19764676 |doi= |url=}}</ref> | ||
*A sessile polyp | *A sessile polyp | ||
*Size can range from 0.5 cm to 5 cm | *Size can range from 0.5 cm to 5 cm | ||
Alternative imaging studies include: | |||
*CT colonography | *CT colonography | ||
*Video [[capsule endoscopy]] (less specific) | *Video [[capsule endoscopy]] (less specific) | ||
| Line 109: | Line 110: | ||
== Treatment == | == Treatment == | ||
=== Medical Therapy === | === Medical Therapy === | ||
There is no medical | There is no medical therapy for villous adenoma; the mainstay of therapy is surgical removal. | ||
=== Surgery === | === Surgery === | ||
| Line 115: | Line 116: | ||
=== Prevention === | === Prevention === | ||
Effective measures for the primary prevention of villous adenoma include periodic screening for patients with family history of [[familial adenomatous polyposis]]. | ====Primary Prevention==== | ||
Effective measures for the primary prevention of villous adenoma include periodic screening for patients with family history of [[familial adenomatous polyposis]]. | |||
====Secondary Prevention==== | |||
Secondary prevention strategies include annual [[occult blood test]] and colonoscopy every ten years for patients above the age of 50. | |||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
Revision as of 13:51, 22 August 2016
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: Adenomatous polyps; VA; TVA
Overview
Villous adenoma (also known as adenomatous polyp) is a type of polyp that grows in the gastrointestinal tract; it occurs most commonly in the colon. Villous adenoma may result in malignant (cancerous) transformation.[1] Villous adenoma was first discovered by Helwig in 1946.[2] According to the World Health Organization, villous adenoma may be classified into tubular, tubulovillous, and villous (most common) subtypes. Villous adenoma arises from epithelial tissue, which is normally part of the lining of the colon. The estimated risk of malignant transformation among villous adenomas is between 15% and 25%. Genes associated with the development of villous adenoma include APC, TP53, K-ras, and BAT-26. The prevalence of villous adenoma is approximately 3.5 per 100,000 individuals worldwide. The most potent risk factors in the development of villous adenoma include familial syndromes such as Turcot syndrome, juvenile polyposis syndrome, and Cowden disease). Surgical removal is the mainstay of therapy for villous adenoma. Exploratory colonoscopy and cautery snare is the most common approach to the diagnosis and treatment of villous adenoma. Effective measures for the primary prevention of villous adenoma include periodic screening of patients with family history of familial adenomatous polyposis. Secondary prevention strategies include annual occult blood test and colonoscopy every ten years for patients above the age of 50.
Historical Perspective
Villous adenoma was first discovered by Helwig in 1946.[2]
Classification
Villous adenoma may be classified into 3 subtypes according to appearance:[3]
- Tubular
- Tubulovillous
- Villous (most common)
Pathophysiology
Pathogenesis
The pathogenesis of villous adenoma is characterized by overgrowth of epithelial tissue with glandular characteristics.[3]
Genetics
Genes associated with the development of villous adenoma include:[3]
Gross Pathology
On gross pathology, characteristic findings of villous adenoma include:[3]
- Polypoid or sessile mass
- Cauliflower-like in appearance
Microscopic Pathology
On microscopic histopathological analysis, characteristic findings of villous adenoma include:
- Nuclear changes at the surface of the mucosa
- Cigar-shaped (elongated) nucleus (length:width > 3:1) with nuclear hyperchromasia
- Large round nuclei
- Nuclear crowding
- Positive Ki-67
Causes
Villous adenomas are commonly idiopathic. The most common known cause of villous adenoma is familial adenomatous polyposis.
Differentiating Villous Adenoma from Other Diseases
Villous adenoma must be differentiated from other diseases that cause abnormal growth of tissue projecting from a mucous membrane such as:
- Colorectal cancer
- Inflammatory fibroid polyp
Epidemiology and Demographics
Prevalence
The prevalence of villous adenoma is approximately 3.5 per 100,000 individuals worldwide. The prevalence of adenomas increases with age.
Age
Patients of all age groups may develop villous adenoma.
Gender
Males are more commonly affected with villous adenoma than females.
Race
Villous adenoma more commonly affects caucasians.
Risk Factors
Common risk factors in the development of villous adenoma include:
- Familial adenomatous polyposis
- Peutz–Jeghers syndrome
- Turcot syndrome
- Juvenile polyposis syndrome
- Cowden disease
- Bannayan–Riley–Ruvalcaba syndrome (Bannayan-Zonana syndrome)
- Gardner's syndrome
Natural History, Complications and Prognosis
Natural History
The majority of patients with villous adenoma remain asymptomatic for years. Early clinical features may include flatulence, bloating, and abdominal pain. If left untreated, patients with villous adenoma may progress to develop colorectal cancer.[3]
Complications
Common complications of villous adenoma include:
- Bleeding
- Obstruction
- Bowel torsion
Prognosis
The prognosis of villous adenoma is generally good and the 5-year mortality is approximately 89%. Prognosis becomes poorer with malignant transformation of the lesion. The estimated risk of malignant transformation of villous adenoma is from 15% to 20%.
Diagnosis
Symptoms
Villous adenoma is commonly asymptomatic. Villous adenoma symptoms are often non-specific. Symptoms of villous adenoma may include:
- Flatulence
- Abdominal pain
- Constipation
- Diarrhea
- Cramping
- Pencil-thin stools
Physical Examination
Patients with villous adenoma commonly appear well. Physical examination findings are often non-specific. Physical examination may demonstrate:
- Bright red blood on digital rectal examination
- Rectal mass
Laboratory Findings
There are no specific laboratory findings associated with villous adenoma. In some cases, patients with villous adenoma may demonstrate positive fecal occult blood test or hypokalemia.[4]
Other diagnostic studies
Colonoscopy is the diagnostic modality of choice for villous adenoma. On colonoscopy, characteristic findings of villous adenoma include:[3]
- A sessile polyp
- Size can range from 0.5 cm to 5 cm
Alternative imaging studies include:
- CT colonography
- Video capsule endoscopy (less specific)
Treatment
Medical Therapy
There is no medical therapy for villous adenoma; the mainstay of therapy is surgical removal.
Surgery
Surgical removal is the mainstay of therapy for villous adenoma. Colonoscopy is both diagnostic and therapeutic. Cautery snare in conjunction with exploratory colonoscopy is the most common approach to both the diagnosis and treatment of villous adenoma.[3]
Prevention
Primary Prevention
Effective measures for the primary prevention of villous adenoma include periodic screening for patients with family history of familial adenomatous polyposis.
Secondary Prevention
Secondary prevention strategies include annual occult blood test and colonoscopy every ten years for patients above the age of 50.
References
- ↑ Villous adenoma
- ↑ 2.0 2.1 Helwig E.B. Adenoma of the large bowel in children. . American Journal of Diseases in Children. 1946;72:289–95
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Osifo OD, Akhiwu W, Efobi CA (2009). "Small intestinal tubulovillous adenoma--case report and literature review". Niger J Clin Pract. 12 (2): 205–7. PMID 19764676.
- ↑ Villous adenoma. Wikipedia. https://en.wikipedia.org/wiki/Villous_adenoma Accessed on May 3, 2016