eMedicine Specialties > Gastroenterology > Colon

Villous Adenoma: Differential Diagnoses & Workup

Author: Alnoor Ramji, MD, FRCPC, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, Canada
Coauthor(s): Eric M Yoshida, MD, MHSc, FRCPC, FACP, Program Director of Adult Gastroenterology Training Program, Assistant Professor, Department of Medicine, Division of Gastroenterology, University of British Columbia
Contributor Information and Disclosures

Updated: Aug 29, 2009

Differential Diagnoses

Familial Adenomatous Polyposis
Peutz-Jeghers Syndrome

Other Problems to Be Considered

Adenocarcinoma
Tubular adenoma
Cowden disease
Granular cell tumor
Hyperplastic polyp
Inflammatory polyps
Juvenile polyps
Lymphoid polyps
Mucosal prolapse
Solitary rectal ulcer
Pseudopolyposis
Diffuse colonic hemangiomatosis

Workup

Laboratory Studies

  • Complete blood cell count: A low hemoglobin level and a classic low mean cell volume (MCV) suggest iron deficiency anemia, but these values can be within reference ranges or can be considered nonspecific findings if small polyps are present.
  • Iron studies: Obtain ferritin levels, serum iron levels, and transferrin saturation values. Patients with iron-deficiency anemia have low ferritin and serum iron levels and low transferrin saturation.
  • Fecal occult blood testing (FOBT): Only 20-40% of patients with adenomas have positive test findings, usually resulting from distal and larger polyps. Of those patients with fecal occult blood, 5-10% have colon cancer. Annual screening by FOBT results in reduced mortality from colon cancer.
  • Genetic studies: These are not performed routinely in the evaluation of sporadic polyps.
  • Stool genetic studies: DNA from colon cancer is shed into the fecal stream in greater quantities than DNA from normal colonic mucosa. Studies are ongoing for detection of multiarray assay for common mutations in colon cancer, including APC, p53, K-ras, and BAT-26 mutations. Unfortunately, most detected cases have been advanced tumors. This screening test has the potential of noninvasiveness and ease of use.

Imaging Studies

  • Double-contrast barium enema
    • Double-contrast barium enemas have a higher sensitivity compared to single-contrast barium enemas. Sensitivity increases with polyp size.
    • Compared to colonoscopy, barium enema detected 32% of polyps smaller than 6 mm in diameter, 53% of polyps between 6 mm and 10 mm, and 48% of polyps larger than 10 mm. A false-positive rate of 5-10% is found because of improper cleaning of the bowel. Diverticulosis or redundant bowel can result in a false-negative rate of 10%, especially in the rectosigmoid. The accuracy of the procedure also can have an element of operator-dependence.
    • For all structural evaluations of the large bowel, use sigmoidoscopy with a barium enema.
  • Computed tomographic colonography (virtual colonoscopy)
    • Computed tomographic colonography is a newer method that is not as sensitive as colonoscopy, although it has the advantage of being less invasive. This scanning still requires bowel preparation.
    • A large variability exists in the effectiveness of computed tomographic colonoscopy as a screening tool. Differences in studies are due in part to differing computed tomographic technologies. When compared to colonoscopy, computed tomographic colonography was able to identify 55-93.8% of all polyps larger than 1 cm, 71-88.7% of polyps between 0.5 cm and 0.9 cm, and only 39% of polyps smaller than 0.6 cm. More studies comparing colonoscopy with virtual colonoscopy are needed before making firm recommendations regarding the role of virtual colonoscopy in screening for colon polyps.
  • Upper GI series and small bowel follow-through: These studies detect small bowel adenomas and can help investigate the small bowel for polypoid lesions beyond the reach of the conventional upper endoscope. They also help detect mass abnormality in 50-80% of patients and can help successfully define neoplasms in 30-44% of patients.
  • Video capsule endoscopy: This study has provided an increasingly effective method to assess the small bowel. Video capsule endoscopy is not used as a screening tool for colonic polyps.

Procedures

  • Endoscopy is the most sensitive method of diagnosing polyps, and it also allows therapeutic intervention.
    • Adequate bowel cleansing is necessary prior to many procedures. Several preparations are marketed for bowel cleansing (eg, polyethylene glycol 3350 [GoLYTELY, NuLYTELY], magnesium citrate [Citroma], senna [X-Prep]) in preparing patients for surgery or gastrointestinal procedures, such as endoscopy, colonoscopy, and barium x-ray studies.
    • Bowel cleansing preparations may be used with various dietary preparations (eg, clear liquid diet 1-2 d before surgery or procedure) and are convenient to administer on an outpatient basis.
  • Sigmoidoscopy
    • Flexible sigmoidoscopy allows for evaluation of the distal bowel to 60 cm. Compared to the previously used rigid sigmoidoscope, the flexible one can detect up to 3 times more adenomas, primarily because it can be inserted further.
    • Some guidelines recommend flexible sigmoidoscopy every 3-5 years in conjunction with annual FOBT for the screening of colon cancer.
    • Overall, the role of flexible sigmoidoscopy is becoming increasingly limited in the screening and diagnosis of colon cancer.
    • Patients do not require full bowel preparation.
  • Colonoscopy
    • Colonoscopy is the most accurate method for detection of polyps and is the first-line procedure of choice. The sensitivity for detecting polyps by colonoscopy compared to double-contrast barium enema is 94% and 67%, respectively. Although accuracy is operator-dependent, colonoscopy is regarded as the criterion standard.2,3
    • Villous adenomas at colonoscopy are usually bulky, sessile, soft, velvety, and friable. However, colonoscopic appearance is not diagnostic of histology.
    • Chromoendoscopy and magnifying endoscopy techniques use dye or magnification to identify and classify the pit pattern of small lesions. This allows a more predictive model on the final histology.4,5
    • Difficulties with colonoscopy include patient discomfort, the need for patient sedation, and material risks of complications (eg, perforation, hemorrhage). Colonoscopy also costs more to perform than barium enema. Note that the accuracy of colonoscopy findings is operator-dependent, with reports of missing up to 15% of small polyps (<8 mm) in a tandem study. No large polyps were missed in this study.
    • Risk of perforation is less than 0.1%. After colonoscopic polypectomy, the risks of perforation and significant bleeding are 0.2% and 1%, respectively.
  • Esophagogastroduodenoscopy is used to help investigate for small bowel adenomas. Visualization of the duodenum is limited.
  • Enteroscopy is used to help investigate for small bowel adenomas. Visualization beyond the conventional endoscope (occasionally up to the ileum) depends on the skill of the operator.
  • Endoscopic retrograde cholangiopancreatography is used to help investigate for adenomas at the ampulla of Vater and allows for biopsy and therapeutic procedures if biliary obstruction is a concern. The risk of complicating pancreatitis is reportedly 3-5%.

Histologic Findings

Adenomatous epithelium has abnormal cellular differentiation with hypercellularity and variable amounts of mucin. The predominant cell type is columnar epithelium, and immature goblet cells may be observed. The dysplastic cells demonstrate elongated nuclei, are hyperchromatic, and have a picket-fence appearance.

Villous histology is characterized by glands arranged in long fingerlike fronds from the polyp surface down to the polyp stroma. Projections usually extend straight down with minimal or no branching.

Staging

Dysplasia is subdivided into mild, moderate, and severe categories.

  • Mild dysplasia is characterized by uniform loss of mucin and hyperchromatic and elongated cells. Glands appear branched and budding.
  • Moderate dysplasia has more prominent nucleoli with increased crowding of cells.
  • In severe dysplasia, increased nuclear pleomorphism, prominent and numerous nucleoli, and increased nuclear-to-cytoplasmic ratio occur. With continued cell proliferation, glands appear to form within glands, with a disordered cribriform appearance, and appear as carcinoma in situ.

More on Villous Adenoma

Overview: Villous Adenoma
Differential Diagnoses & Workup: Villous Adenoma
Treatment & Medication: Villous Adenoma
Follow-up: Villous Adenoma
Multimedia: Villous Adenoma
References
Further Reading
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References

  1. Wark PA, Wu K, van 't Veer P, Fuchs CF, Giovannucci EL. Family history of colorectal cancer: a determinant of advanced adenoma stage or adenoma multiplicity?. Int J Cancer. Jul 15 2009;125(2):413-20. [Medline].

  2. Terhaar Sive Droste JS, Craanen ME, van der Hulst RW, et al. Colonoscopic yield of colorectal neoplasia in daily clinical practice. World J Gastroenterol. Mar 7 2009;15(9):1085-92. [Medline]. [Full Text].

  3. Martinez ME, Baron JA, Lieberman DA, et al. A pooled analysis of advanced colorectal neoplasia diagnoses after colonoscopic polypectomy. Gastroenterology. Mar 2009;136(3):832-41. [Medline].

  4. Denis B, Peters C, Chapelain C, et al. Diagnostic accuracy of community pathologists in the interpretation of colorectal polyps. Eur J Gastroenterol Hepatol. Aug 18 2009;epub ahead of print. [Medline].

  5. Bokemeyer B, Bock H, Huppe D, et al. Screening colonoscopy for colorectal cancer prevention: results from a German online registry on 269000 cases. Eur J Gastroenterol Hepatol. Jun 2009;21(6):650-5. [Medline].

  6. Cole BF, Logan RF, Halabi S, et al. Aspirin for the chemoprevention of colorectal adenomas: meta-analysis of the randomized trials. J Natl Cancer Inst. Feb 18 2009;101(4):256-66. [Medline].

  7. Baron JA, Cole BF, Sandler RS, Haile RW, Ahnen D, Bresalier R, et al. A randomized trial of aspirin to prevent colorectal adenomas. N Engl J Med. Mar 6 2003;348(10):891-9. [Medline].

  8. Bond JH. Colon polyps and cancer. Endoscopy. Jan 2001;33(1):46-54. [Medline].

  9. Bond JH. Colorectal cancer update. Prevention, screening, treatment, and surveillance for high-risk groups. Med Clin North Am. Sep 2000;84(5):1163-82, viii. [Medline].

  10. Bond JH. Polyp guideline: diagnosis, treatment, and surveillance for patients with colorectal polyps. Practice Parameters Committee of the American College of Gastroenterology. Am J Gastroenterol. Nov 2000;95(11):3053-63. [Medline].

  11. Bond JH. Polyp guideline: diagnosis, treatment, and surveillance for patients with nonfamilial colorectal polyps. The Practice Parameters Committee of the American College of Gastroenterology. Ann Intern Med. Oct 15 1993;119(8):836-43. [Medline].

  12. Cotton PB, Durkalski VL, Pineau BC, Palesch YY, Mauldin PD, Hoffman B, et al. Computed tomographic colonography (virtual colonoscopy): a multicenter comparison with standard colonoscopy for detection of colorectal neoplasia. JAMA. Apr 14 2004;291(14):1713-9. [Medline].

  13. Day DW, Morson BC. The adenoma-carcinoma sequence. In: Morson BC, ed. The Pathogenesis of Colorectal Cancer. Philadelphia: WB Saunders; 1978:58-71.

  14. DuBois RN, Giardiello FM, Smalley WE. Nonsteroidal anti-inflammatory drugs, eicosanoids, and colorectal cancer prevention. Gastroenterol Clin North Am. Dec 1996;25(4):773-91. [Medline].

  15. Farnell MB, Sakorafas GH, Sarr MG, Rowland CM, Tsiotos GG, Farley DR, et al. Villous tumors of the duodenum: reappraisal of local vs. extended resection. J Gastrointest Surg. Jan-Feb 2000;4(1):13-21, discussion 22-3. [Medline].

  16. Gibbs ER, Walton GF, Kent RB 3rd, Laws HL. Villous tumors of the ampulla Vater. Am Surg. Jun 1997;63(6):467-71. [Medline].

  17. Heald RJ, Bussey HJ. Clinical experiences at St. Mark's Hospital with multiple synchronous cancers of the colon and rectum. Dis Colon Rectum. Jan-Feb 1975;18(1):6-10. [Medline].

  18. Itzkowitz SH, Kim YS. Colonic polyps and polyposis syndromes. In: Feldman M, Scharschmidt BF, Sleisenger MH. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, and Management. 6th ed. Philadelphia, Pa: WB Saunders; 1997:467-71.

  19. Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Schuman LM, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med. May 13 1993;328(19):1365-71. [Medline].

  20. Morson BC, Dawson IMP. Gastrointestinal Pathology. Oxford: Blackwell Scientific; 1972.

  21. O'Brien MJ, Winawer SJ, Zauber AG, Gottlieb LS, Sternberg SS, Diaz B, et al. The National Polyp Study. Patient and polyp characteristics associated with high-grade dysplasia in colorectal adenomas. Gastroenterology. Feb 1990;98(2):371-9. [Medline].

  22. Pickhardt PJ, Choi JR, Hwang I, Butler JA, Puckett ML, Hildebrandt HA, et al. Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults. N Engl J Med. Dec 4 2003;349(23):2191-200. [Medline].

  23. Sandler RS, Halabi S, Baron JA, Budinger S, Paskett E, Keresztes R, et al. A randomized trial of aspirin to prevent colorectal adenomas in patients with previous colorectal cancer. N Engl J Med. Mar 6 2003;348(10):883-90. [Medline].

  24. Schrock TR. Colonoscopy for colorectal cancer: too much, too little, just right. ASGE Distinguished Lecture 1993. Gastrointest Endosc. Nov-Dec 1993;39(6):848-51. [Medline].

  25. Seitz U, Bohnacker S, Seewald S, Thonke F, Brand B, Braiutigam T, et al. Is endoscopic polypectomy an adequate therapy for malignant colorectal adenomas? Presentation of 114 patients and review of the literature. Dis Colon Rectum. Nov 2004;47(11):1789-96; discussion 1796-7. [Medline].

  26. Stryker SJ, Wolff BG, Culp CE, Libbe SD, Ilstrup DM, MacCarty RL. Natural history of untreated colonic polyps. Gastroenterology. Nov 1987;93(5):1009-13. [Medline].

  27. Winawer SJ, Zauber AG, Fletcher RH, Stillman JS, O'Brien MJ, Levin B, et al. Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society. Gastroenterology. May 2006;130(6):1872-85. [Medline].

  28. Winawer SJ, Zauber AG, Ho MN, O'Brien MJ, Gottlieb LS, Sternberg SS, et al. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med. Dec 30 1993;329(27):1977-81. [Medline].

  29. Winawer SJ, Zauber AG, Ho MN, O'Brien MJ, Gottlieb LS, Sternberg SS, et al. The National Polyp Study. Eur J Cancer Prev. Jun 1993;2 Suppl 2:83-7. [Medline].

  30. Winawer SJ, Zauber AG, O'Brien MJ, Ho MN, Gottlieb L, Sternberg SS, et al. Randomized comparison of surveillance intervals after colonoscopic removal of newly diagnosed adenomatous polyps. The National Polyp Study Workgroup. N Engl J Med. Apr 1 1993;328(13):901-6. [Medline].

  31. Zauber AG, Winawer SJ. Initial management and follow-up surveillance of patients with colorectal adenomas. Gastroenterol Clin North Am. Mar 1997;26(1):85-101. [Medline].

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Further Reading

Clinical guidelines

Guidelines for colonoscopy surveillance after polypectomy: A consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society.
American Cancer Society - Disease Specific Society
American Gastroenterological Association Institute - Medical Specialty Society.  2006 May.  17 pages.  NGC:006080

Surveillance and management of groups at increased risk of colorectal cancer.
New Zealand Guidelines Group - Private Nonprofit Organization.  2004 May.  84 pages.  NGC:003655

Quality indicators for colonoscopy.
American College of Gastroenterology - Medical Specialty Society
American Society for Gastrointestinal Endoscopy - Medical Specialty Society.  2006 Apr.  13 pages.  NGC:004969

Colorectal cancer screening.
Institute for Clinical Systems Improvement - Private Nonprofit Organization.  1995 May (revised 2008 Jun).  27 pages.  NGC:006580

Routine aspirin and non-steroidal anti-inflammatory drug (NSAID) prophylaxis for colorectal cancer prevention.
United States Preventive Services Task Force - Independent Expert Panel.  2007 Mar.  5 pages.  NGC:005452

Clinical trials

Randomised Trial of NBI for Adenoma Detection

Selenium in Treating Patients With Adenomatous Colorectal Polyps

A Prospective, Single Blinded Study for Predicting Colon Polyp Histology With Narrow Band Imaging (NBI)

Chemoprevention of Colorectal Adenomas

Prevention of Progression of Duodenal Adenomas in Patients With Familial Adenomatous Polyposis (PreDuoFAP)


Related eMedicine topics

 Pancreas, Mucinous Cystic Neoplasm

Papillary Tumors

Neoplasms of the Endocrine Pancreas

Colon, Polyps

Hereditary Colorectal Cancer

Colon Cancer, Adenocarcinoma

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Keywords

villous adenoma, tubulovillous adenoma, adenomatous polyps, colonic tumor, colonic neoplasm, papillary adenoma, malignancy, tubular adenoma, tubulovillous adenoma, tubulo-villous adenoma, colonoscopy, adenocarcinomas, rectal cancer, colon cancer, colonic villous adenomas

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Contributor Information and Disclosures

Author

Alnoor Ramji, MD, FRCPC, Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, Canada
Alnoor Ramji, MD, FRCPC is a member of the following medical societies: Canadian Society of Internal Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Eric M Yoshida, MD, MHSc, FRCPC, FACP, Program Director of Adult Gastroenterology Training Program, Assistant Professor, Department of Medicine, Division of Gastroenterology, University of British Columbia
Disclosure: Nothing to disclose.

Medical Editor

Manoop S Bhutani, MD, FACG, FACP, Professor, Department of Medicine, Division of Gastroenterology, Director, Center for Endoscopic Ultrasound, Co-Director, Center for Endoscopic Research, Training and Innovation, University of Texas Medical Branch at Galveston
Manoop S Bhutani, MD, FACG, FACP is a member of the following medical societies: American Association for the Advancement of Science, American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Institute of Ultrasound in Medicine, and American Society for Gastrointestinal Endoscopy
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

James L Achord, MD, Professor Emeritus, Department of Medicine, Division of Digestive Diseases, University of Mississippi School of Medicine
James L Achord, MD is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Medical Association, American Society for Gastrointestinal Endoscopy, Mississippi State Medical Association, New York Academy of Sciences, Sigma Xi, and Southern Medical Association
Disclosure: Nothing to disclose.

CME Editor

Alex J Mechaber, MD, FACP, Associate Dean for Undergraduate Medical Education, Associate Professor of Medicine, University of Miami Miller School of Medicine
Alex J Mechaber, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, and Society of General Internal Medicine
Disclosure: Nothing to disclose.

Chief Editor

Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law Medicine and Ethics, American Trauma Society, Association of American Medical Colleges, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

 
 
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