The pathology of Lynch Syndrome

Lynch Syndrome (LS) is a relatively common cause of inherited colorectal carcinoma which have many typical gross and microscopic features. Histopathologists play a critical role in identifying such tumours but also in screening cases for LS using modern molecular techniques. Immunohistochemistry for mismatch repair proteins, microsatellite instability testing and mutation analysis of key genes such as BRAF are important tools in this regard. Pathologists must be aware of the advantages and limitations of all these tests.