Colon
Syndromes
MUTYH associated polyposis
Author: Raul S. Gonzalez, M.D.
Last author update: 2 February 2021
Last staff update: 2 February 2021
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: MUTYH associated polyposis [title]
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Clinical features | Diagnosis | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics description | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Gonzalez RS. MUTYH associated polyposis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumormyhassociated.html. Accessed December 11th, 2024.
Definition / general
- Autosomal recessive polyposis syndrome characterized by development of numerous colon adenomas but usually fewer than in classic familial adenomatous polyposis
Essential features
- Attenuated polyposis syndrome with biallelic MUTYH mutations and no FAP mutation
- Increased risk for colorectal carcinoma
Terminology
- Outdated terms include:
- MYH associated polyposis
- Familial adenomatous polyposis 2
- Autosomal recessive adenomatous polyposis
Epidemiology
- Accounts for < 1% of colorectal carcinoma (Gastroenterology 2009;136:1251)
Sites
- Adenomatous polyps develop in the colon and sometimes in the duodenum
- Colorectal carcinomas are often proximal (Gastroenterology 2010;138:2044)
Clinical features
- Mean age of diagnosis is about 50 years
- Patients often have between 10 and 100 polyps (Int J Cancer 2004;109:680)
- Biallelic mutations confer a 50 fold risk of colorectal carcinoma and monoallelic mutation a 3 fold risk (Cancer Epidemiol Biomarkers Prev 2006;15:312)
- Patients can also develop ovarian, bladder and breast carcinoma, as well as sebaceous gland tumors
Diagnosis
- Molecular testing to confirm biallelic MUTYH mutations
Case reports
- 2 patients with duodenal carcinoma (J Clin Pathol 2006;59:1212)
Microscopic (histologic) description
- Patients most commonly develop colonic tubular adenomas that resemble sporadic adenomas
- Sessile serrated polyps can also occur
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D.
Adenoma associated with MUTYH mutation
Molecular / cytogenetics description
- MUTYH is located at 1p34 and repairs oxidative DNA damage that otherwise can lead to carcinoma (Mod Pathol 2013;26:1371)
- Most common mutations are Y165C and G382D
Differential diagnosis
- Familial adenomatous polyposis and attenuated familial adenomatous polyposis:
- Presentations can overlap but these patients have an APC mutation
Additional references
Board review style question #1
How does MUTYH associated polyposis differ from familial adenomatous polyposis?
- It is autosomal recessive
- Molecular testing cannot confirm the diagnosis
- Patients never develop upper gastrointestinal tract adenomas
- The polyps are all serrated
Board review style answer #1
