# Clinicopathological Features of Superficial Non‐Ampullary Duodenal Epithelial Tumors Involving Brunner's Glands

## TL;DR

This study examines how superficial non-ampullary duodenal tumors interact with Brunner's glands, finding that larger tumors or specific shapes are more likely to involve these glands.

## Contribution

The study provides new insights into the clinicopathological relationship between SNADETs and Brunner's glands, identifying predictive features for gland involvement.

## Key findings

- Submucosal Brunner's gland involvement was observed in 7.0% of SNADETs.
- Lesion size ≥10 mm or 0-IIc morphology predicted gland involvement with 100% sensitivity.
- Non-neoplastic Brunner's glands were found at the vertical margin in 15.1% of endoscopic resections.

## Abstract

Although Brunner's glands (BGs), located in the submucosa of the duodenum, may be involved by tumor cells of superficial non‐ampullary duodenal epithelial tumors (SNADETs), the detailed incidence and histopathological features have not yet been analyzed. This study aimed to clarify the histopathological relationship between SNADETs and BGs.

We retrospectively analyzed SNADETs that were resected at a single center between 2006 and 2021. Resected specimens were histologically evaluated to determine the presence and/or involvement of SNADET in BGs. The relationship between clinicopathological features and tumor involvement in BGs was also assessed.

In total, 114 lesions were included. Direct connection with BGs was seen in 52.6% of SNADETs, and submucosal BG involvement was observed in 7.0% (95% confidence interval 3.1%–13.4%) of SNADETs. The presence of submucosal BG involvement was significantly associated with 0‐IIc morphology, high‐grade dysplasia or carcinoma, and the gastric mucinous phenotype. The presence of either a lesion size 10 mm or greater or 0‐IIc morphology demonstrated a sensitivity of 100%, a specificity of 34.9%, and a false negative rate of 0% for predicting submucosal BG involvement. Moreover, non‐neoplastic BGs were exposed at the vertical margin in 15.1% of endoscopic resection specimens.

SNADETs can have submucosal involvement via BGs, particularly in lesions fulfilling either a size ≥10 mm or a 0‐IIc morphology. These pathological findings suggest that vertical resectability may be relevant in their endoscopic management, although further studies are needed to clarify clinical implications.