Focal MLH1 loss in the SSAD backgrounds. a Haematoxylin and eosin-stained section of an SSAD, with the SSAD background on the right (crypts of interest indicated by arrows) and the dysplastic portion on the left (arrowheads). b MLH1 immunohistochemistry for the same SSAD. There is loss of nuclear MLH1 staining in a proportion of crypts in the SSAD background (arrows), while the dysplastic portion shows complete loss of staining (arrowheads). SSAD, sessile serrated adenoma with dysplasia; SSA, sessile serrated adenoma.