Colon

Polyps

Juvenile (retention) polyp


Editorial Board Member: Wei Chen, M.D., Ph.D.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Maria Kamal, M.D.
Lewis A. Hassell, M.D.

Last author update: 17 November 2021
Last staff update: 17 November 2021

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PubMed Search: Juvenile polyp [title] colon

Maria Kamal, M.D.
Lewis A. Hassell, M.D.
Page views in 2021: 25,893
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Cite this page: Kamal M, Hassell LA. Juvenile (retention) polyp. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorjuvenilepolyp.html. Accessed December 7th, 2022.
Definition / general
Essential features
  • Most common type of pediatric intestinal polyp, with prominent, cystically dilated glands and inflammatory stroma
  • Solitary juvenile polyps have minimal malignant potential; multiple juvenile polyps may indicate a premalignant condition (juvenile polyposis coli or juvenile polyposis syndrome [JPS])
  • Juvenile polyposis syndrome is autosomal dominant and caused by a germline defect in SMAD4 or BMPR1A
Terminology
  • Retention polyps and juvenile hamartomatous polyps (Can J Gastroenterol 2007;21:233)
  • Juvenile polyposis syndrome (WHO 5th edition):
    • > 3 - 5 juvenile polyps in the colorectum or
    • Juvenile polyps throughout the gastrointestinal tract or
    • Any number of juvenile polyps with a positive family history of juvenile polyposis (World J Gastroenterol 2011;17:4839)
    • Other syndromes involving hamartomatous gastrointestinal polyps should be ruled out clinically or by pathological examination
ICD coding
  • ICD-10:
    • K63.5 - polyp of colon
    • D12.6 - benign neoplasm of colon, unspecified
Epidemiology
Sites
  • Majority in distal colon / rectosigmoid
  • Less frequently seen in stomach and small bowel
Pathophysiology
  • Earliest morphologic lesions are focal areas of mucosal hyperplasia, which seem to evolve into minute hyperplastic polyps
  • These become inflamed, frequently with ulceration and scarring of their surface, sealing over some of the crypts, with subsequent cystic dilatation of the crypts, accumulation of mucus within the cysts, enlargement of the structure to form a typical juvenile polyp and further inflammation and scarring
  • In some of the larger polyps, focal epithelial atypia develops
  • Second hypothesis: landscape defect, in which an abnormal stromal environment leads to neoplastic transformation of adjacent epithelium (World J Gastroenterol 2011;17:4839)
  • Juvenile polyposis syndrome is caused by a germline defect in SMAD4 or BMPR1A (Am J Surg Pathol 2011;35:530)
Etiology
  • Juvenile polyposis syndrome is autosomal dominant
Clinical features
Diagnosis
Radiology description
  • Filling defect on barium enema
  • Rounded hypoechoic nodule within the lumen of gastrointestinal tract with a peripheral hyperechoic layer (Ital J Pediatr 2020;46:66)
Radiology images

Images hosted on other servers:

Ultrasonography and color Doppler sonography

Prognostic factors
Case reports
Treatment
  • Many of these polyps outgrow their blood supply, become ischemic and autoamputate
  • For solitary juvenile polyp:
    • Colonoscopy / sigmoidoscopy and polypectomy
    • No further evaluation or followup is needed after polypectomy
    • Adenomatous changes in a juvenile polyp: followup and screening endoscopy is recommended (Clin Colon Rectal Surg 2008;21:280)
  • For juvenile polyposis syndrome:
    • High suspicion of JPS: endoscopic screening of the colon and upper gastrointestinal tract at age 15 or at the time of first symptoms
    • Followup: recommended every 2 to 3 years in patients with juvenile polyposis syndrome
    • Surgery: considered in patients with colorectal polyposis unmanageable by endoscopy (> 50 - 100 polyps), those with severe gastrointestinal bleeding or diarrhea, juvenile polyps with dysplasia and patients with a strong family history of colorectal cancer (World J Gastroenterol 2011;17:4839)
Clinical images

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Endoscopic images

Gross description
  • Sessile or pedunculated hamartomatous polyps
  • 5 mm to 50 mm, typically spherical, lobulated and pedunculated with surface erosion
  • Reference: World J Gastroenterol 2011;17:4839
Gross images

Contributed by Nalini Bansal, M.D.
Multiple polyps Multiple polyps

Multiple polyps



Images hosted on other servers:
Macroscopic appearance

Macroscopic appearance

Microscopic (histologic) description
  • Characterized by an abundance of edematous lamina propria with inflammatory cells and cystically dilated glands lined by cuboidal to columnar epithelium with reactive changes (nonneoplastic, hamartomatous, epithelial retentions)
  • Dilated glands filled with mucus and inspissated inflammatory debris
  • Juvenile polyposis syndrome:
    • Polyps appear similar to sporadic solitary juvenile polyps, although syndromic polyps often have a frond-like growth pattern with less stroma, fewer dilated glands and more proliferative smaller glands
    • JPS polyps frequently show neoplastic changes to the epithelium not common in sporadic solitary juvenile polyps
  • Reference: World J Gastroenterol 2011;17:4839
Microscopic (histologic) images

Contributed by Lewis Hassell, M.D., Nalini Bansal, M.D. and Christopher Hartley, M.D.
Juvenile polyp from stomach

Juvenile polyp from stomach

No dysplasia

No dysplasia

Ulcerated

Ulcerated

Dilated colonic glands Dilated colonic glands

Dilated colonic glands

Dysplasia

Dysplasia


Mild frond-like growth pattern Mild frond-like growth pattern

Mild frond-like growth pattern

Virtual slides

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Pediatric patient

Pediatric patient

Ulcerated

Ulcerated

Juvenile polyposis syndrome histology

Juvenile polyposis syndrome histology

Juvenile polyp from stomach

Positive stains
  • TP53 mutations (p53 mutated pattern staining) can be seen with high grade dysplasia in polyps of juvenile polyposis syndrome
Negative stains
  • p53 shows wild type pattern staining in benign solitary juvenile polyp, as there is no dysplastic change
Molecular / cytogenetics description
  • Germline mutation in the SMAD4 (18q21.1) or BMPR1A (10q23.2) gene is found in 40 - 60% of patients with juvenile polyposis syndrome
  • JPS patients with SMAD4 mutations are associated with more aggressive gastric polyps and appear to have a higher risk for gastric cancer (J Pediatr Gastroenterol Nutr 2019;68:453)
Videos

Histopathology of juvenile polyps

Endoscopy of juvenile polyps

Sample pathology report
  • Colon, polypectomy:
    • Solitary juvenile polyp (see comment)
    • Comment: Negative for dysplasia or malignancy
Differential diagnosis
Board review style question #1

A 5 year old boy presented with rectal bleeding for 1 month. Endoscopic examination revealed a polyp in the sigmoid colon. Histologic details are shown in the image above. What type of polyp is it?

  1. Adenomatous polyp
  2. Hamartomatous polyp
  3. Hyperplastic polyp
  4. Neoplastic polyp
Board review style answer #1
B. Hamartomatous polyp. The picture shows a juvenile polyp with cystically dilated glands in an edematous and inflammatory stroma with ulceration. Juvenile polyp is a hamartomatous polyp.

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Reference: Juvenile (retention) polyp
Board review style question #2
Which of the following is true regarding juvenile polyp?

  1. Most common clinical presentation is intussusception
  2. Mostly seen in proximal stomach
  3. Solitary juvenile polyp has minimal risk of malignant transformation
  4. Uncommon type of pediatric polyp
Board review style answer #2
C. Solitary juvenile polyp has minimal risk of malignant transformation. Juvenile polyp is the most common type of pediatric intestinal polyp, mostly seen in distal colon. Painless rectal bleed is the most common clinical presentation. Solitary juvenile polyps have minimal malignant potential; however, multiple juvenile polyps may indicate a premalignant condition (juvenile polyposis coli or juvenile polyposis syndrome [JPS]).

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Reference: Juvenile (retention) polyp
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