Distinct endoscopic characteristics of sessile serrated adenoma/polyp with and without dysplasia/carcinoma

Sessile serrated adenoma/polyp (SSA/P) is a colorectal polyp that has malignant potential. However, the dysplastic components within an SSA/P can be difficult to detect. This study aimed to clarify the endoscopic characteristics of SSA/P with advanced histology.

We examined 462 endoscopically or surgically resected lesions that were pathologically diagnosed as SSA/P, including 414 without and 41 with cytologic dysplasia, and 7 with invasive carcinoma. We retrospectively studied the clinicopathologic and endoscopic characteristics and performed pit pattern analysis.

A stepwise increase in the size of the SSA/P series was identified along with their dysplastic progression, although 19 of 48 (39.6%) SSA/Ps with dysplasia/carcinoma were ≤10 mm in size. Most lesions were covered with a mucus cap. Macroscopically, (semi)pedunculated morphology, double elevation, central depression, and reddishness were found more frequently in SSA/P with cytologic dysplasia and invasive carcinoma ([semi]pedunculated morphology, 17.1%/28.6%; double elevation, 63.4%/57.1%; central depression, 9.8%/28.6%; reddishness, 39.0%/85.7%) than in those without dysplasia (4.6%, 4.6%, 3.9%, and 3.4%, respectively). Furthermore, the presence of at least 1 of these 4 markers had high sensitivity (91.7%) for identifying the dysplasia/carcinoma within a SSA/P, with a specificity of 85.3%. In the pit pattern analysis, all SSA/Ps without dysplasia exhibited type II pit pattern only, whereas 94.4% of SSA/Ps with dysplasia/carcinoma showed type II in addition to type III_L, IV, V_I, or V_N pit patterns.

In an SSA/P series, endoscopic characteristics, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, in addition to the use of magnifying endoscopy, may be useful to accurately diagnose advanced histology within an SSA/P.