A Lynch Syndrome Family With Germline MLH1 c.931A>G Showing Preserved Tumor MMR Immunostaining but MSI‐H Status: A Case Report
This case highlights that preserved tumor MMR immunostaining does not exclude Lynch syndrome when clinical suspicion is high and Concurrent MSI and MMR immunohistochemistry, interpreted together with tumor sequencing and germline testing, may improve diagnosis, treatment selection, and familial risk assessment.