Endoscopic features of submucosal invasive non-ampullary duodenal carcinomas.

BACKGROUND AND AIM: It is imperative to distinguish superficial non-ampullary duodenal carcinomas (NADCs) between intramucosal and submucosal invasive carcinoma for treatment selection. The aim of this study was to evaluate the clinicopathological differences of intramucosal and submucosal carcinoma.

METHODS: This was a retrospective, single-center study comprising 134 patients with 137 superficial NADCs during May 2005 and March 2018. Clinicopathological characteristics and treatment outcomes data were used to perform a comparative analysis of endoscopic findings, preoperative diagnoses of depth of cancer and treatment outcomes of histologically diagnosed intramucosal and submucosal carcinoma.

RESULTS: Of the 137 NADCs, 125 (91%) were intramucosal and 12 (9%) were submucosal. The proportion of submucosal carcinoma was significantly higher on the oral side of the papilla than on the anal side (16% vs. 1%, P = 0.002). Submucosal tumor-like appearance was more frequent in submucosal than in intramucosal carcinoma (58% vs. 13%, P = 0.001). There was no significant difference in tumor diameter between the groups, but 33% of submucosal carcinomas were ≤10 mm. Correct preoperative diagnosis of depth was achieved in 33% of submucosal carcinoma. Submucosal carcinoma was frequently underestimated when tumor diameters were ≤10 mm. Conversely, intramucosal carcinoma was frequently overestimated when the tumor was ≥30 mm and had thickness or giant nodules. Lymph node metastasis was found in one submucosal carcinoma patient.

CONCLUSIONS: The possibility of submucosal invasion should be considered when NADCs are located on the oral side of the papilla or have submucosal tumor-like appearance even if tumor diameters are ≤10 mm.