The pathology of gastric and duodenal polyps: current concepts

Endoscopic and pathological features of neoplastic transformation of gastric hyperplastic polyps: Retrospective study of 4010 cases

BACKGROUND

Hyperplastic polyps, which represent 30%-93% of all gastric epithelial polyps, are the second most common type of gastric polyps after fundic gland polyps. They were previously considered to have no risk of neoplastic transformation. Recently, an increasing number of cases of gastric hyperplastic polyps (GHPs) combined with neoplastic changes have been reported; however, the specific mechanism underlying their transformation has not been thoroughly explored.

AIM

To investigate the clinical, endoscopic, and pathological characteristics of the neoplastic transformation of GHPs and explore the risk factors.

METHODS

A retrospective analysis was performed on 4010 cases of GHPs diagnosed by gastroscopy and pathological examination at the hospital from 2005 to 2021. In total, 3874, 119, and 17 cases were in the group without intraepithelial neoplasia (IN), with low-grade IN, and with high-grade IN, respectively. The data analysis examined the association of endoscopic and pathological features with risk factors for neoplastic transformation. Factors with significant differences were entered into univariate logistic regression, followed by multivariate logistic regression analysis.

RESULTS

Univariate analysis revealed diameter, multiple polyp presence, redness, rough surface, lobulation, erosion, Yamada classification, location, and gastric mucosa were risk factors for neoplastic transformation. Multivariate analysis showed that age > 65 years [odds ratio (OR) = 1.789; 95% confidence interval (CI): 1.227-2.609; P = 0.003], male sex (OR = 1.680; 95%CI: 1.158-2.438; P = 0.006), multiple polyps (OR = 1.851; 95%CI: 1.230-2.784; P = 0.003), pedunculated or semi-pedunculated shape (OR = 2.722; 95%CI: 1.689-4.388; P < 0.001), and polyp diameter were significantly associated with GHPs that demonstrated neoplastic transformation. Compared with chronic superficial gastritis, autoimmune gastritis, atrophic gastritis, and gastritis with IN were independent risk factors for neoplastic transformation [(OR = 2.672; 95%CI: 1.559-4.579; P < 0.001), (OR = 1.876; 95%CI: 1.134-3.103; P = 0.014), and (OR = 5.299; 95%CI: 3.173–8.849; P < 0.001), respectively].

CONCLUSION

Male sex, age > 65 years, multiple polyps, pedunculated or semi-pedunculated shape, polyp size > 1 cm, and specific background gastric mucosa are key indicators for predicting neoplastic transformation of GHPs.

Causal links between circulatory inflammatory cytokines and risk of digestive polyps: a Mendelian randomization analysis

Background

There is a high morbidity of polyps in the digestive tract, and certain subtypes of polyps are thought to induce cancer progression and often recur, which may be associated with chronic inflammation. Mendelian randomization (MR) can help identify potential causative relationships and inform early treatment action.

Methods

We performed a bidirectional two-sample MR analysis implementing the results from genome-wide association studies for 41 serum cytokines from 8,293 Finnish individuals, and three types of polyps from European ancestry, respectively, including gastric polyp (6,155 cases vs. 341,871 controls), colonic polyp (22,049 cases vs. 332,368 controls) and gallbladder polyp (458 cases vs. 340,083 controls). Inverse-variance weighted (IVW), weight median (WM), and MR-Egger methods were used for calculating causal estimates. Furthermore, Bayesian model averaging MR (MR-BMA) method was employed to detect the dominant causal circulatory cytokines with adjustment for pleiotropy effects.

Results

Our univariable MR using inverse-variance weight method identified causal associations of IL-2ra (OR: 0.892, 95%CI: 0.828-0.961, p = 0.003), MIG (OR: 1.124, 95%CI: 1.046-1.207, p = 0.001) and IL-18 (OR: 0.912, 95%CI: 0.852-0.977, p = 0.008) with gastric polyp, MIP1b (OR: 0.956, 95%CI: 0.927-0.987, p = 0.005) and IL-6 (OR: 0.931, 95%CI: 0.870-0.995, p = 0.035) with colonic polyp and IL-9 (OR: 0.523, 95%CI: 0.345-0.794, p = 0.0007) with gallbladder polyp. Finally, our MR-BMA analysis prioritized MIG (MIP = 0.332, MACE = 0.022; PP: 0.264, MSCE = 0.059), IL-18 (MIP = 0.302, MACE = -0.020; PP: 0.243, MSCE = -0.059) and IL-2ra (MIP: 0.129; MACE: -0.005; PP: 0.112, MSCE: -0.031) for gastric polyp, and MIP1b (MIP = 0.752, MACE = -0.033; PP: 0.665, MSCE = -0.044) and IL-6 (MIP: 0.196; MACE: -0.012; PP: 0.140, MSCE: -0.064) for colonic polyp, and IL-9 (MIP = 0.936, MACE = -0.446; PP: 0.781, MSCE = -0.478) for gallbladder polyp as the top-ranked protective factors.

Conclusion

Our research advances the current understanding of the function of certain inflammatory biomarker pathways in the genesis and malignant mutation of polyps in the digestive tract. Deeper substantiation is necessary to assess the potential of these cytokines as pharmacological or lifestyle targets for digestive polyps prevention.

Oxyntic Gland Neoplasms - From Adenoma to Advanced Gastric Cancer: A Review of 29 Cases

PURPOSE

Oxyntic gland neoplasm (OGN) is a rare condition that can be classified as oxyntic gland adenoma (OGA) or gastric adenocarcinoma of fundic-gland type (GA-FG). GA-FG primarily presents as early gastric cancer, with only a few reported cases of advanced gastric cancer (AGC). We aimed to investigate the clinicopathological features of OGN and describe an aggressive variant.

MATERIALS AND METHODS

We investigated a total of 29 cases, including a patient with double primary cases, diagnosed with OGN or differentiated-type adenocarcinoma with GA-FG morphology, between November 2016 and April 2022. We analyzed 54 pathological specimens and reviewed their clinicopathological, endoscopic, and histological features. The lesions were reclassified as OGA or GA-FG, and immunohistochemical (IHC) staining for MUC-5AC and MUC-6 was performed on available resected GA-FG cases.

RESULTS

The median patient age was 65 years and males accounted for 58.6% of patients. Most cases occurred in the body horizontally (69.0%) and on the greater curvature side cross-sectionally (48.3%). Endoscopically, type 0-IIa (41.4%) and a subepithelial tumor-like appearance (24.1%) were the most common findings. Histologically, there were 8 cases of OGA (27.6%) and 21 cases of GA-FG (72.4%). In GA-FG, MUC-6 was positive in 13 cases (81.3%), whereas MUC-5AC was positive in 8 cases (50.0%). Three cases presented as AGCs.

CONCLUSIONS

Although OGNs are generally considered low-grade, they can present as AGCs and may exhibit features of lymphovascular or perineural invasion. Recognizing the clinicopathological features and accurately diagnosing OGN are important for providing adequate treatment.

Consideration of a Novel Surgical Approach in the Management of Gastric Adenocarcinoma and Proximal Polyposis Syndrome

Investigators at MSKCC highlight a novel surgical approach to manage GAPPS.

Development of Gastric Polyps: 15 Years of Proton Pump Inhibitor Therapy

Gastroesophageal reflux disease (GERD) is a common disease affecting millions of people worldwide. Proton pump inhibitors (PPI) are the most common drugs used to treat this acid-related disorder due to their high efficacy and fewer side effects. However, long-term use of these drugs can cause histopathological changes, including cystic dilation of gastric fundic glands. The present report describes a 53-year-old man with chronic GERD and daily use of PPIs 20 mg once a day for over 15 years. This case demonstrates the association between PPI and the development of fundic gland polyps.

Feasibility and efficacy of endoscopy with blue laser imaging for the detection and diagnosis of cardia polyps: A single-center randomized controlled study

OBJECTIVE

To compare the detection rate and diagnostic accuracy of cardia polyps using endoscopy with blue laser imaging (BLI) and white-light imaging (WLI).

METHODS

Patients were randomly divided into the BLI group and WLI group according to the endoscopic procedures. BLI followed by WLI was conducted in the BLI group, whereas WLI followed by BLI examination was conducted in the WLI group. The number, size, microstructure, and microvascular patterns of cardia polyps detected were recorded. Biopsy of the polyps was then performed.

RESULTS

The detection rate of cardia polyps in the BLI group was higher than that in the WLI group (7.87% vs 4.22%, P = 0.018). The rate of overlooked lesions in the BLI group was lower than in the WLI group (0.64% vs 3.38%, P = 0.003). The diagnostic coincidence rate between magnifying BLI and histopathology was 88.16%. The sensitivity, specificity, positive predictive value and negative predictive value for the diagnosis of neoplastic lesions by magnifying endoscopy with BLI were 90.91%, 87.69%, 55.56%, and 98.28%, respectively. The most remarkable patterns for predicting inflammatory polyps were the prolonged and fine network patterns (sensitivity 71.43%, specificity 93.75%). Small round combined with honeycomb patterns were the most common among fundic gland polyps (sensitivity 80.00%, specificity 98.48%). Neoplastic lesions presented as villous or ridge-like combined with core vascular or unclear pattern for both microvascular and microstructure patterns.

CONCLUSION

BLI is more effective than WLI in the detection and diagnosis of cardia polyps, and magnifying endoscopy with BLI may help diagnose such lesions.

High frequency electrocoagulation resection effect analysis and prognosis observation in the treatment of patients with gastric polyps under painless gastroscopy

To explore high frequency electrocoagulation resection effect in treatment of patients with gastric polyps under painless gastroscopy. Sixty-four patients with gastric polyps were randomly divided into experimental group (32 cases) and control group (32 cases). Experimental group received basic treatment drugs for 8 weeks, and then treated with painless gastroscope high-frequency electrocoagulation resection. Control group was also given basic treatment drugs for 8 weeks, and then received high-frequency electrocoagulation resection under ordinary gastroscope. The patients in both groups were given rabeprazole sodium enteric coated capsules for 4 weeks. The improvement of symptom score, postoperative gastric mucosal healing and comprehensive curative effect of the 2 groups were observed after treatment. The patients with polyps cured under gastroscopy were subjected to a 6-month follow-up period during which gastroscopy was performed to assess the recurrence of polyps. Symptom scores comparison after treatment showed that experimental group had obvious advantages in improving epigastric fullness, fatigue and loose stool in patients with gastric polyps (P < .01 or P < .05). Gastric mucosa healing in experimental group was better at 2 weeks after operation (P < .05), showing no difference 4 weeks after operation (P > .05). Comprehensive curative effect comparison showed that the experimental group was better (P < .01), showing no difference in long-term efficacy (P > .05). In treating patients with gastric polyps, painless endoscopic high-frequency electrocoagulation resection effect is better, which not only promotes postoperative rehabilitation in patients but also reduces complications incidence, demonstrating a high level of safety. Therefore, it is highly recommended for widespread adoption and application.

Risk factors associated with recurrence of gastric hyperplastic polyps: a single-center, long-term, retrospective cohort study

BACKGROUND

The likelihood of recurrence of gastric hyperplastic polyps (GHPs) following endoscopic resection and the need for long-term follow-up remain unknown. We, therefore, aimed to investigate the factors associated with the recurrence and cumulative incidence of GHPs over a 10-year period.

METHODS

Between May 1995 and December 2020, 1,018 GHPs > 1 cm were endoscopically resected from 869 patients. Medical records of these patients were retrospectively reviewed and their clinical features and outcomes were assessed. Groups of GHPs with recurrence and those without recurrence group were compared, and univariate and multivariable analyses were performed to identify the potential risk factors for GHP recurrence.

RESULTS

A total of 104 (12.0%) patients who underwent endoscopic removal of GHPs experienced recurrence. Compared to patients without recurrent GHPs, those with recurrent GHPs showed considerably larger median polyp size (28 mm vs. 14 mm, P < 0.001), a higher proportion of multiple polyps (41.3% vs. 29.3%, P = 0.020), polyps with lobulation (63.5% vs. 40.3%, P = 0.001), and exudate (63.5% vs. 46.8%, P = 0.001). Compared to the local recurrence (n = 52) group, the metachronous recurrence (n = 52) group had larger median polyp size (20 mm vs. 16 mm, P = 0.006) as well as higher rates of polyp lobulation (86.5% vs. 40.4%, P < 0.001) and exudate (82.7% vs. 44.4%, P = 0.001). After primary GHP excision, the cumulative incidence of recurrence was 7.2%, 12.7%, and 19.6% at 2 years, 5 years, and 10 years, respectively.

CONCLUSION

The incidence of GHP recurrence following endoscopic excision increased as the follow-up period increased, especially in patients whose GHPs were large-sized, multiple, or characterized by surface exudates/lobulations.

Oxyntic Gland Adenoma in a Patient With Refractory Reflux

A 58-year-old African American male was referred for endoscopic evaluation due to a persistent nine-year history of reflux. Previous endoscopy nine years ago revealed a small hiatal hernia and chronic gastritis caused by Helicobacter pylori (H. pylori), which was treated with triple therapy. During the current endoscopic evaluation, findings consistent with reflux esophagitis were identified, along with the discovery of an incidental 6 mm sessile polyp in the gastric fundus. Pathological examination revealed the presence of an oxyntic gland adenoma (OGA). Otherwise, the stomach was found to be unremarkable endoscopically and histologically. OGA is a rare gastric neoplasm that is primarily observed in Japan, with very few reported cases in North America. Studies have suggested a potential association with antacids, while the role of H. pylori in the development of OGA remains controversial. Our patient's OGA was completely resected during the endoscopy, with no recurrence noted on the three-month follow-up.

Gastric villous adenoma: a case report and review of the literature

BACKGROUND

Villous adenoma is the one subtype of adenomatous polyp that is very uncommon in the stomach. Data regarding clinical characteristics, natural history, and prognosis were scarce.

CASE PRESENTATION

This report presented an 87-year-old Thai woman with a large gastric villous adenoma incidentally revealed in a computed tomography of chest for the evaluation of right pleural effusion. The esophagogastroduodenoscopy demonstrated a huge, glossy, proliferative polypoid mass involving gastric cardia, fundus, and a lesser curve of the upper body. The pathological report confirmed villous adenoma with low grade dysplasia. Although surgical resection was suggested, the patient denied any treatment due to advanced age and multiple comorbidities. She was generally well after 12 months of clinical and radiologic surveillance.

CONCLUSION

From literature review, only 14 cases of gastric villous adenoma were reported to date. Most of the lesions were large and symptomatic. Malignancy presented in 43% of the cases. Nevertheless, our patient remained asymptomatic without surgical removal following a 12-month period.

Endoscopic mucosal resection of gastrointestinal polyps with a novel low-temperature plasma radio frequency generator: a non-inferiority multi-center randomized control study

BACKGROUND

To evaluate the efficacy and safety of novel plasma radio frequency generator and its single-use polypectomy snares for endoscopic mucosal resection (EMR) of gastrointestinal (GI) polyps.

METHODS

A total of 217 patients with 413 GI polyps were recruited from four centers in China. Patients were assigned to experimental or control groups using a central randomization method. The experimental group used the novel plasma radio frequency generator and its matched single-use polypectomy snares (Neowing, Shanghai), while the control group used the high-frequency electrosurgical unit (Erbe, Germany) and disposable electrosurgical snares (Olympus, Japan). The primary endpoint was the en bloc resection rate, and the non-inferiority margin was set at 10%. Secondary endpoint included operation time, coagulation success rate, intraoperative and postoperative bleeding rate, and perforation rate.

RESULTS

The en bloc resection rate was 97.20% (104/107) in the experimental group and 95.45% (105/110) in the control group (P = 0.496). The operation time was 29.14 ± 20.21 min in the experimental group and 30.26 ± 18.74 min in the control group (P = 0.671). The average removal time of a single polyp in the experimental group was 7.52 ± 4.45 min, which was slightly shorter than that in the control group 8.90 ± 6.67 min, with no statistical difference (P = 0.076). The intraoperative bleeding rates of the experimental group and control group were 8.41% (9/107) and 10.00% (11/110), respectively (P = 0.686). No intraoperative perforation occurred in either group. The postoperative bleeding rates of the experimental group and the control group were 1.87% (2/107) and 4.55% (5/110), respectively (P = 0.465). No postoperative perforation occurred in the experimental group (0/107), while one case of delayed perforation occurred in the control group (1/110, 0.91%). There was no statistical difference between the two groups.

CONCLUSIONS

Endoscopic mucosal resection of GI polyps with the novel plasma radio frequency generator is safe and effective, and non-inferior to the conventional high-frequency electrosurgical system.

Phosphomannomutase 2 (PMM2) variants leading to hyperinsulinism-polycystic kidney disease are associated with early-onset inflammatory bowel disease and gastric antral foveolar hyperplasia

Phosphomannomutase 2 (PMM2) deficiency causes Congenital Disorder of Glycosylation (PMM2-CDG), but does not have a recognised association with Inflammatory Bowel Disease (IBD). A distinct clinical syndrome of hyperinsulinism and autosomal recessive polycystic kidney disease (HIPKD) arises in the context of a specific variant in the PMM2 promotor, either in homozygosity, or compound heterozygous with a deleterious PMM2 variant. Here, we describe the development of IBD in three patients with PMM2-HIPKD, with onset of IBD at 0, 6, and 10 years of age. In each case, intestinal inflammation coincided with the unusual finding of gastric antral foveolar hyperplasia. IBD disease was of variable severity at onset but well controlled with conventional and first-line biologic treatment approaches. The organ-level pattern of disease manifestations in PMM2-HIPKD-IBD may reflect a loss of cis-acting regulatory control by hepatocyte nuclear factor 4 alpha (HNF4A). Analysis of published transcriptomic data suggests that IBD most likely arises due to an impact on epithelial cellular function. We identify a specific pattern of variation in PMM2 as a novel association of early-onset IBD with distinctive gastric pathology.

Endoscopic Submucosal Dissection in the Stomach and Duodenum: Techniques, Indications, and Outcomes

Gastric endoscopic submucosal dissection (ESD) is established for management of early gastric cancer (EGC). Diagnosis of EGC relies on adequate endoscopic assessment involving lesion size, histopathology, presence of ulceration, and depth of invasion. Absolute indications for endoscopic resection of EGC are if patients are presumed to have a less than 1% risk of lymph node metasta endoscopic submucosal dissectionsis, and long-term outcomes are similar to those with surgical gastrectomy. Duodenal ESD is more technically difficult and requires expertise in ESD in other locations.

Metabolic obesity phenotypes: a friend or foe of digestive polyps?-An observational study based on National Inpatient Database

OBJECTIVE

Obesity is associated with an increased risk of digestive polyps, whereas all obesity are not created equally. The role of metabolic states in occurrence risks of polyps among individuals with varying degrees of obesity remains unknown. Our study aimed to evaluate the association between metabolic obesity phenotypes and the occurrence of digestive polyps.

RESEARCH DESIGN AND METHODS

Data from 9,278,949 patients between 2016 and 2018 from the National Inpatient Sample (NIS) database, a nationally representative database of all discharges from US health-care hospitals, were analyzed. According to obesity phenotype, the study population was classified into four groups: metabolically healthy nonobese (MHNO), metabolically unhealthy nonobese (MUNO), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). We calculated the incidence rates of various digestive polyps (stomach/duodenum, colon and rectum polyps) among these participants by searching the hospital records for ICD-10 diagnosis codes indicating each gastric, duodenum, colon or rectal polyps. The multiple stepwise regression analysis and further in-depth subgroup analysis were used to determine the associations between metabolic obesity phenotypes and the occurrence of digestive polyps.

RESULTS

In the total or female population, those with the MUNO and MUO phenotypes had significantly higher prevalence of digestive polyps compared with individuals with the MHNO or MHO phenotypes (all p < 0.05) and a significant difference was not found between MUNO and MUO phenotypes (p > 0.05). Obese subjects seem to be more likely to develop stomach and duodenum polyps or colon polyps than non-obese subjects in metabolically healthy people of males (MHO vs. MHNO, p < 0.05), whereas obesity status seems to have little effect on the occurrence of digestive polyps in metabolically healthy people of females (MHO vs. MHNO, p>0.05). After adjusting for the potential confounders, the MHO, MUNO and MUO phenotypes were all risk factors for stomach and duodenum polyps (OR = 1.46, 95% CI: 1.36-1.58, p< 0.01; OR = 1.19, 95% CI: 1.14-1.25, p< 0.01; OR = 1.44, 95% CI: 1.35-1.55, p< 0.01, respectively) or colon polyps (OR = 1.28, 95% CI: 1.21-1.35, p< 0.01; OR = 1.18, 95% CI: 1.14-1.22, p< 0.01; OR = 1.46, 95% CI: 1.38-1.54, p< 0.01, respectively) compared with the MHNO phenotype，especially in menopausal female. Interestingly, we also observed in further in-depth subgroup analysis that metabolic abnormalities may have a greater impact on the occurrence of digestive polyps than obesity (all p < 0.05).

CONCLUSIONS

Both metabolic abnormities and obesity were associated with a higher risk of digestive polyps. The effect of metabolism on digestive polyp occurrence may be stronger than that of obesity, highlighting the importance of abnormal metabolic status modification regardless of obesity status. Clinical intervention should not only focus on obesity, but also on metabolic abnormalities to decrease digestive polyp risk.

Advances and horizons for artificial intelligence of endoscopic screening and surveillance of gastric and esophageal disease

The development of artificial intelligence in endoscopic assessment of the gastrointestinal tract has shown progressive enhancement in diagnostic acuity. This review discusses the expanding applications for gastric and esophageal diseases. The gastric section covers the utility of AI in detecting and characterizing gastric polyps and further explores prevention, detection, and classification of gastric cancer. The esophageal discussion highlights applications for use in screening and surveillance in Barrett's esophagus and in high-risk conditions for esophageal squamous cell carcinoma. Additionally, these discussions highlight applications for use in assessing eosinophilic esophagitis and future potential in assessing esophageal microbiome changes.

Risk Factors of Non-en Bloc Resection and Non-R0 Resection During Endoscopic Resection in the Treatment of Superficial Duodenal Epithelial Lesions

Background

Superficial duodenal epithelial lesions are precancerous lesions of duodenal carcinoma. Upper gastrointestinal endoscopy has been widely used in the screening and treatment of this disease. This article will collect the data of patients who underwent endoscopic resection of superficial duodenal epithelial lesions in our hospital from 2010 to 2021, aiming to describe the efficacy and safety of endoscopic resection, as well as to explore the risk factors of non-en bloc resection and non-R0 resection.

Methods

Patients who underwent endoscopic resection for superficial duodenal epithelial lesions in our hospital from January 2010 to September 2021 were selected. The curative effect was expressed by the en bloc resection rate and R0 resection rate. The safety was expressed by intra- or postoperative complications, such as bleeding and perforation. The potential risk factors of curative effect were analyzed by logistic regression.

Results

A total of 137 patients were included. The en bloc resection rate was 95.62% (131/137), R0 resection rate was 91.97% (126/137), the postoperative bleeding rate was 2.19% (3/137), and no postoperative perforation was found. The histology result of ectopic gastric mucosa was the risk factor of non-en bloc resection (OR: 8.86, 95% CI: 1.38-56.92); the lesion size ≥2 cm was the risk factor of non-R0 resection (OR: 12.55, 95% CI: 2.95-53.38).

Conclusion

Endoscopic resection is a safe and effective method for the treatment of superficial duodenal epithelial lesions. The histology result of ectopic gastric mucosa was the risk factor of non-en bloc resection and the lesion size ≥2 cm was the risk factor of non-R0 resection.

Histologic heterogeneity and syndromic associations of non-ampullary duodenal polyps and superficial mucosal lesions

BACKGROUND

Duodenal polyps and superficial mucosal lesions (DP/SMLs) are poorly characterised.

AIMS

To describe a series of endoscopically-diagnosed extra-ampullary DPs/SMLs.

METHODS

This is a retrospective study conducted in a tertiary referral Endoscopy Unit, including patients who had DPs or SMLs that were biopsied or removed in 2010-2019. Age, gender, history of familial polyposis syndromes, DP/SML characteristics were recorded. Histopathological, immunohistochemical and molecular analyses were performed.

RESULTS

399 non-ampullary DP/SMLs from 345 patients (60.6% males; median age 67 years) were identified. Gastric foveolar metaplasia represented the most frequent histotype (193 cases, 48.4%), followed by duodenal adenomas (DAs; 77 cases, 19.3%). Most DAs (median size 6 mm) were sessile (Paris Is; 48%), intestinal-type (96.1%) with low-grade dysplasia (93.5%). Among syndromic DAs (23%), 15 lesions occurred in familial adenomatous polyposis 1, two were in MUTYH-associated polyposis and one was in Peutz-Jeghers syndrome (foveolar-type, p53-positive, low-grade dysplasia). Only one (3.3%) tubular, low-grade DA showed mismatch repair deficiency (combined loss of MLH1 and PMS2, heterogeneous MSH6 expression), and it was associated with a MLH1 gene germline mutation (Lynch syndrome).

CONCLUSION

DPs/SMLs are heterogeneous lesions, most of which showing foveolar metaplasia, followed by low-grade, intestinal-type, non-syndromic DAs. MMR-d testing may identify cases associated with Lynch syndrome.

Small Bowel Epithelial Precursor Lesions: A Focus on Molecular Alterations

The wider use of gastrointestinal endoscopic procedures has led to an increased detection of small intestinal preneoplastic and neoplastic epithelial lesions, most of which are identified in the duodenum and ampullary region. Like their malignant counterparts, small intestinal glandular precursor lesions, which include adenomas and hamartomas, may arise sporadically or be associated with hereditary tumor syndromes, such as familial adenomatous polyposis, MUTYH-associated polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. In addition, dysplastic, preinvasive lesions have been observed adjacent to small bowel adenocarcinomas complicating immune-related disorders, such as celiac or Crohn’s disease. Adenomatous lesions may exhibit an intestinal-type, gastric-type, or, very rarely, serrated differentiation, related to different molecular pathogenetic mechanisms. Finally, in the background of multiple endocrine neoplasia 1 syndrome, precursor neuroendocrine growths have been described. In this review we offer a comprehensive description on the histo-molecular features of the main histotypes of small bowel epithelial precursors lesions, including: (i) sporadic adenomas (intestinal-type and gastric-type; non-ampullary and ampullary); (ii) syndromic adenomas; (iii) small bowel dysplasia in celiac and Crohn’s disease; (iv) serrated lesions; (v) hamartomatous lesions; and (vi) neuroendocrine precursor lesions.