GPR: 2021 - Week 21

From MGH Learn Pathology

Clinical history

65 year old woman with a history of hereditary hemorrhagic telangiectasia presents with a large gastric mass.


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Juvenile Polyposis Syndrome (JPS)
  • Germline mutations in SMAD4 or BMPR1A in 50-60% of JPS patients.
  • Associated with hereditary hemorrhagic telangiectasias.
  • SMAD4 mutations commonly have upper GI polyps.
  • 2/3 of polyps are pedunculated.
  • Larger lesions are multilobulated and ulcerated.
  • Patients with JPS have an increased risk of gastric and colorectal carcinoma.



Lynch syndrome (HNPCC)

  • AKA- Hereditary Nonpolyposis Colorectal Cancer
  • Autosomal dominant inheritance.
  • Majority of cases are due to germline mutation in DNA mismatch repair (MLH1, MSH2, MSH6, or PMS2 )
  • Most tumors are located in the proximal colon and have FEW adenomas, thus nonpolyposis.
  • Increased risk of colorectal carcinoma.



Familial Adenomatous Polyposis

  • Autosomal dominant inherited germline mutation in APC gene (upregulates the Wnt pathway)
  • Polyps are located mostly in the sigmoid colon and rectum.
  • Can have hundreds to thousands of polyps.
  • Attenuated form has fewer polyps (usually <100).



Attenuated Familial Adenomatous Polyposis

  • Zoomed in



Classic Familial Adenomatous Polyposis

  • Hundreds to thousands of polyps.

  • Dr. Vikram Deshpande
  • Emily Schlotterbeck
  • Dr. Christopher Mount
  • Dr. Melanie Kwan

This week's Gross Pathology Roundup was presented by Albert Sy MD on 2021-05-24.