Although KRAS mutations are not unique to MLA [3,10,39,40,53] and can be identified in 20–30% of the endometrial endometrioid carcinoma [54,55,56], with the additional use of histological features and immunophenotypes characteristic of MLA, the identification of KRAS mutations can confirm MLA diagnosis. This evidence concerns the gene KRAS and endometrial endometrioid carcinoma.