Sessile Festoon Adenoma (SFA) is a subtype of colorectal adenoma and colorectal scallop polyp. It is a precursor lesion of colorectal adenocarcinoma. They sit mainly in the right colon.

They appear as flat or slightly raised lesions, often extensive and sometimes multiple, corresponding to lesions of hyperplastic polyposis.

This lesion is associated with BRAF mutations suggesting that these lesions may be an early stage of the process leading to the emergence of sporadic colonic cancers with an "unstable microsatellite" (MSI) phenotype. Histopathologyedit code

The deep part of the glands is often enlarged, has a tendency to divide into two or three branches and to be horizontalized, that is to say to arrange itself parallel to the muscularis mucosa and not perpendicular to it, as in conventional hyperplastic polyps and traditional scalloped adenomas.

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