Superficially serrated adenoma（SuSA）の病理組織像と分子異常

Superficially Serrated Adenoma（SuSA）

要旨●SuSAとは，管状の腺腫様腺管から構成され，表層に限局した鋸歯状構造を伴う大腸ポリープである．大半のSuSAはS状結腸または直腸に発生し，KRAS変異＋RSPO融合/過剰発現という遺伝子異常を有しており，分子異常の観点からも鋸歯状病変の新たなサブタイプと考えられる．SuSAはしばしばTSAの辺縁に随伴して認められ，このような病変ではSuSA成分とTSA成分で同一の遺伝子異常がみられることから，SuSAはTSAの前駆病変と考えられる．

　Superficially serrated adenoma（SuSA）is a distinct type of colorectal polyp characterized by adenomatous ducts with serrated structures, which are limited to the upper layers of the lesion. These polyps are predominantly found in the sigmoid colon and rectum. At the molecular level, SuSAs typically exhibit concurrent KRAS mutations and RSPO fusions or overexpression. They frequently occur in association with traditional serrated adenomas（TSAs）. The SuSA and TSA components of SuSA-associated TSAs display identical genetic abnormalities. These findings suggest that SuSA represents a morphologically and molecularly distinct subtype of colorectal serrated lesions and is a precursor to TSA.