Atypical identification of Lynch syndrome by immunohistochemistry and microsatellite instability analysis on jejunal adenocarcinoma

Dawn E Mcilvried,Ruemu E Birhiray,Jim Z Lu

doi:10.1186/1897-4287-9-s1-p27

Dawn E Mcilvried, Ruemu E Birhiray + Show 1 more

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https://doi.org/10.1186/1897-4287-9-s1-p27

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Abstract

Background Lynch syndrome (LS) is a hereditary cancer condition associated with germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2. This condition has been traditionally described in terms of an increased risk for early-onset colorectal and endometrial cancers. Individuals with LS additionally have an increased risk to develop other cancers including ovarian, gastric, urinary tract, hepatobiliary tract, small bowel, brain, and skin cancers. The preferred method of genetic testing for LS is to initially perform microsatellite instability (MSI) analysis and/or immunohistochemistry (IHC) staining as a test on the tumor tissue of an affected individual. If abnormal, this testing would indicate that a germline mismatch repair gene mutation is more likely to explain the cancer and, if IHC is performed, may also indicate which gene to test first via molecular analysis. MSI/IHC has been more widely validated for colon and endometrial cancers as opposed to other cancers associated with this condition.

Highlights

Lynch syndrome (LS) is a hereditary cancer condition associated with germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2
Case report We report a 66-year-old male patient with past history of multiple cancers including colon and kidney cancer, and recently diagnosed with jejunal adenocarcinoma
MSH6 mutations have been associated with a higher cumulative risk for endometrial cancer with a later age of onset as compared to other mismatch repair gene mutations [1-5], and cancers other than colon and endometrial may account for as much as 50% of cancer reported with MSH6 mutations [6]

Summary

Introduction

Lynch syndrome (LS) is a hereditary cancer condition associated with germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2. Case report We report a 66-year-old male patient with past history of multiple cancers including colon and kidney cancer, and recently diagnosed with jejunal adenocarcinoma. History of Lynch-associated cancers included brain, gastric and endometrial cancer, noted to have later ages of onset (Figure 1).

Results

Conclusion