Pyloric gland adenoma (PGA) is a distinct subtype of duodenal adenoma. PGA has been increasingly recognized as a histologically and molecularly distinct entity; however, its endoscopic features have not been precisely described. This study aims to investigate the endoscopic characteristics of duodenal PGA, including the association of their putative precursors, Brunner's gland hyperplasia (BGH), and gastric epithelial heterotopia/metaplasia (GEM/H).

This study was a single-center, retrospective case series. Fourteen consecutive patients with duodenal PGA were retrieved from the pathological database. PGA was diagnosed according to the World Health Organization classification.

The median tumor size was 22.5 mm (range: 12-40 mm), and 79% of cases were located in the first part of the duodenum. Six PGAs demonstrated high-grade dysplasia. PGA could be classified into two subtypes based on their appearance: villous lobulated type and smoothly protruding type. BGH and GEM/H were identified in the background mucosa in 28% and 7% of the cases, respectively. BGH was more abundant in the background mucosa of the PGA group than in the control group (p < 0.05). Six PGAs (43%) exhibited high-grade dysplasia, and no significant difference was observed in the endoscopic findings between low- and high-grade dysplasia.

The 14 patients with PGA demonstrated characteristic endoscopic findings. BGH and GEM/H might be precursors of PGA.

Mucosal adenocarcinoma of the descending duodenum is a very rare gastrointestinal tumor. Due to its low incidence, it has rarely been the focus of clinical and pathological studies. The clinical manifestations of these tumors are usually nonspecific, and they are easily misdiagnosed or missed. Pathological diagnosis is the gold standard for diagnosis, but due to the small number of cases, the relevant pathological characteristics and diagnostic criteria are not completely clear. The purpose of this study was to deepen the understanding of the diagnosis and treatment of this disease and to provide a clinical guidance.

A 61-year-old woman who was hospitalized with recurrent abdominal pain for more than 20 days. The patient developed epigastric pain with no obvious cause more than 20 days prior, mainly left epigastric pain and middle epigastric pain, and presented persistent dull pain without nausea or vomiting, fever or chills. The patient was treated at a local hospital, gastroscopy revealed a new lesion in the circum-intestinal cavity in the descending part of the duodenum, and pathological biopsy revealed mucous adenocarcinoma in the descending part of the duodenum. Currently, for further diagnosis and treatment, the patient is admitted to our hospital for surgical treatment for "malignant tumor of the duodenum" in the outpatient department.

Mucosal adenocarcinoma of the descending duodenum has a high misdiagnosis rate and missed diagnosis rate, clinical manifestations lack specificity, and pathological diagnosis is the main basis for diagnosis.

With the recent increase in the frequency of duodenal tumor detection, significant progress has been made in endoscopic diagnosis and treatment. Although the first guidelines were issued in Japan, patient treatment varies widely among institutions. There is a need for improving the quality of endoscopic diagnosis and more curative and safer treatments. Biopsy is the standard diagnostic method; however, the diagnostic accuracy of endoscopic biopsy is not so high. Therefore, the differentiation of superficial non-ampullary duodenal epithelial tumors from non-neoplastic lesions is being developed. The incidence of lymph node and distant metastases of duodenal epithelial tumors is extremely rare in intramucosal carcinomas, and they are considered good candidates for endoscopic treatment if the technical difficulties can be resolved. Adverse events associated with endoscopic treatment are greatly reduced at advanced facilities through novel resection and closure methods, and further improvements are expected in the future. Clarifying the risk of metastatic recurrence may lead to the development of more appropriate treatments and curative resection criteria.

We held four upper gastrointestinal tract advanced diagnostic endoscopy sessions from the 89th to the 92nd Congress of the Japan Gastroenterological Endoscopy Society. The most common region addressed was the stomach in 25 presentations, followed by the esophagus in 23, duodenum in five, and other in one. Looking at techniques discussed, the most common image enhancement method discussed was narrowband imaging in 29 presentations, blue laser imaging, and linked color imaging (LCI) in 10 each, dual red imaging in three, and autofluorescence imaging in one. Furthermore, there were presentations of new techniques such as M-Chromo-LCI and acetic acid-indigo carmine mixture LCI. There were also six presentations regarding probe-based confocal laser endomicroscopy, and one of endocytoscopy techniques. We also saw presentations of images of gastric subepithelial tumors within the submucosa, 3D endoscopy, the development of computer-aided detection systems for early cancers, and fluorescent imaging.

The pathologic diagnosis of duodenal tumors is a developing field; however, its overview remains unclear. We describe a rare case of a duodenal gastric-type neoplasm in a 50-year-old woman. She visited her primary care doctor with complaints of upper abdominal pain, tarry stools, and shortness of breath on exertion. She was admitted owing to a stalked polyp with erosion and hemorrhage in the descending part of the duodenum. Endoscopic mucosal resection (EMR) was performed on the polyp. Histologically, the resected polyp was a lipomatous lesion in the submucosal layer, composed of mature adipose tissues. Scattered irregular lobules of Brunner's gland-like structures with well-preserved construction but mildly enlarged nuclei and occasional conspicuous nucleoli of the constituent cells were observed. The resection margin was negative. EMR findings of the duodenal polyp showed a gastric epithelial tumor within a lipoma, a rare histological type that has not been reported previously. This tumor may be classified as a "neoplasm with uncertain malignant potential" in a lipoma, an intermediate category between adenoma and invasive adenocarcinoma. There is no consensus on treatment, and careful follow-up is recommended. This is the first report of a duodenal gastric-type neoplasm with uncertain malignant potential in a lipoma.

In recent years, there have been significant advances in the endoscopic resection (ER) procedures of superficial nonampullary duodenal epithelial tumors (SNADETs). A preoperative endoscopic diagnosis is thus deemed necessary in determining the indication for subsequent ER. For the histologic and endoscopic diagnosis of SNADETs, understanding the mucin phenotype is inevitable. Recently, two diagnostic algorithms for the differential diagnosis of SNADETs from nonneoplastic lesions under magnifying endoscopy with narrow-band imaging have been proposed. In addition, various endoscopic approaches have been proposed to differentiate low- and high-grade adenomas/carcinomas, including white light endoscopy, magnifying image-enhanced endoscopy, and endocytoscopy. These methods, however, have not been standardized with respect to the classification of their findings and the validation of their diagnostic accuracy. Moreover, there are still concerns with respect to the histologic criteria required to establish a SNADETs diagnosis. Standardization in the histologic and endoscopic diagnosis of SNADETs is needed.