Gastric Polyps Detected Incidentally during Gastroscopy and Follow-Up Results.

(1) Background: We aimed to identify the possible relationship between various diseases of the upper digestive system and colon polyps by analyzing patients with gastric polyps and evaluating the cancers and diseases accompanying the polyps. (2) Methods: Each patient's age; gender; polyp type and size; presence of Helicobacter pylori (H. pylori), atrophic gastritis, and intestinal metaplasia; status of whether cancer developed during follow-up; status of whether a colonoscopy was performed or not; and colon pathologies detected during colonoscopy were analyzed retrospectively using hospital records. (3) Results: Between the study dates, 19,214 esophagogastroduodenoscopies were performed in the endoscopy unit of our hospital. Gastric polyps were detected in 178 (0.9%) patients. No significant relationship was found between the gastric polyp size and the occurrence of gastric cancer or gastrointestinal system malignancy (p > 0.05). A colonoscopy was performed in 86 of the 178 patients who underwent gastroscopy. The frequency of polyp detection during colonoscopy was statistically significantly higher in patients with gastric polyps than in patients without gastric polyps (p < 0.001). (4) Conclusions: New prospective studies are needed regarding the relationship between gastric polyps and gastrointestinal system diseases. Going forward, a colonoscopy will be required in gastric polyp patients, especially with FGP.

Gastric polyps: a retrospective cohort analysis of 23,668 endoscopies indicates changing epidemiological and phenotypic characteristics.

Introduction: Growing adoption of endoscopic procedures in clinical practice has gradually increase the detection rate of gastric polypoid lesions. Aim: To identify the epidemiologic characteristics of gastric polyps as well as changes of these parameters during a 15-year period. Material and methods: We reviewed all the upper endoscopies archived in our database reporting a polypoid lesion from 2003 to 2018. Demographic data, indication for endoscopy, morphological characteristics of polyps, histology, and presence of Helicobacter pylori were collected. We compared the abovementioned data between 2 periods: 2003-2010 and 2010-2018. Results: A total of 989 (4.2%) patients from 23,668 reviewed were identified to harbour a polypoid lesion. Mean patient age was 63.2 years, with 58.8% being female. Most polyps (65.2%) were less than 5 mm in diameter and located in the fundus. Hyperplastic polyps (HPs) were the predominant type (28.6%) while fundic gland polyps (FGPs) were found in 24.1% of patients. Adenomas were the least common type (2.7%). Other pathology was identified in 43.3%. Comparison between the 2 periods revealed a rise of FGPs against HPs with a concomitant shift of location from antrum to fundus and an increase in the number of polyps per patient. Conclusions: FGPs and HPs were the most common polyps found in our cohort, with a change of their pattern during the 15 years. It is imperative to acknowledge the distinct characteristics of gastric polyps so as to properly assess the malignant potential that some of them, or their surrounding gastric mucosa, harbour.

Long-term endoscopic change of gastric polyp associated with administration of vonoprazan.

Vonoprazan (VPZ) has been available in Japan since 2015. Endoscopic features of proton-pump inhibitor (PPI)-related gastric mucosal changes, including fundic gland and hyperplastic polyps, have been observed. However, the relationship between gastric polyps and VPZ remains unclear. A 65-year-old man with reflux esophagitis-associated symptoms refractory to PPI was referred to our hospital. VPZ (20 mg) was administered for 3 weeks, which proved effective. Afterward, VPZ dose was reduced to 10 mg; the reflux symptoms worsened, and 20 mg VPZ was restarted. Afterward, esophagogastroduodenoscopy (EGD) revealed a gradually enlarging gastric polyp in the cardia. After 5 years of VPZ administration, the patient developed a reddish polyp (approximately 10 mm) with a whitish substance in the cardia. Based on the clinical course, the polyp was considered to have enlarged because of the long-term VPZ administration. After being informed of the endoscopic findings, the patient decided to discontinue VPZ. One year after VPZ discontinuation, EGD revealed a shrunken polyp (5 mm). Long-term acid suppression causes hypergastrinemia, which may lead to gastric mucosal changes, including gastric polyps. There are few case reports of a decrease in the number and size of gastric polyps after VPZ discontinuation. Hence, some VPZ-induced endoscopic changes may be reversible.

Proton Pump Inhibitor Associated Multiple Gastric Hyperplastic Polyps With Uncontrollable Bleeding: A Case Report.

BACKGROUND/AIM: The long-term use of proton pump inhibitors (PPIs) has been reported to be strongly associated with the development of fundic gland polyps (FGPs). Conversely, a few cases of gastric hyperplastic polyps (GHPs) associated with PPI use have been reported. We experienced a case of PPI-associated multiple GHPs with uncontrollable bleeding. CASE REPORT: A 64 year old man with a history of rheumatoid arthritis presented to the hospital with complaints of vertigo and black stools. Blood tests revealed anemia and hypoproteinemia. Esophagogastroduodenoscopy (EGD) showed blood and black residue accumulated in the stomach. The source of the bleeding was multiple hyperplastic polyps. Bleeding could be stopped even with fasting, and total blood transfusions amounted to 28 units of RBCs were required in 18 days. After the cessation of PPI, EGD showed that the polyps had almost disappeared. Pathological diagnosis of resected polyp was hyperplastic polyp, which was characterized by capillary hyperplasia and edema. Gastrin receptors were over-expressed in the foveolar epithelium and not in the capillaries. Methotrexate (MTX)-induced portal hypertensive gastroenteropathy was revealed during follow-up. We consider that the effect of portal hypertension may have caused the capillary hyperplasia. CONCLUSION: Although PPI-related polyps are usually fundic gland polyps and do not cause life-threatening adverse events, we experienced PPI-related GHPs in which hemostasis was difficult to control.

Incidental Finding of Well-Differentiated Duodenal Neuroendocrine Tumor on Diagnostic Upper Endoscopy.

Neuroendocrine tumors (NETs) are rare and slow-growing. They are often found incidentally, and patients typically present with vague symptoms. This is a case report detailing an 83-year-old female who presents with signs and symptoms consistent with esophageal stricture and was incidentally found to have a duodenal NET. Treatment typically involves surgical removal and carries a good prognosis. With complete surgical resection of localized tumors, the chance of progression or recurrence is low.

Severe Anemia from Multiple Gastric Hyperplastic Polyps in a Hemodialysis Patient after Long-term Use of a Proton-pump Inhibitor.

A 90-year-old man on maintenance hemodialysis was admitted due to severe symptomatic anemia. Biopsies under esophagogastroduodenoscopy demonstrated that the cause of anemia was intermittent blood oozing from multiple gastric hyperplastic polyps. Even after successful eradication of Helicobacter pylori, he showed hypergastrinemia (480 pg/mL) owing to esomeprazole (proton-pump inhibitor) therapy for the past 4.5 years to treat reflux esophagitis. Seven months after we switched esomeprazole to famotidine (H2-receptor antagonist), those gastric polyps and anemia were remarkably ameliorated with lowered gastrin levels. This case indicates that long-term use of a proton-pump inhibitor triggers chronic hypergastrinemia, leading to gastric hyperplastic polyps and subsequent severe anemia.

Hyperplastic polyp-like adenoma: a subtype of colonic adenoma with a proliferative zone confined to the lower two-thirds of the crypt.

BACKGROUND: The proliferative zone of colonic adenomas is confined to the upper third of the crypt or is scattered along its entire axis. In contrast, there are unusual adenomas with proliferative zones confined to the lower two-thirds of the crypt. We investigated the frequency and endoscopic features of adenomas with lower proliferative zones. METHODS: We retrospectively reviewed consecutive patients who underwent colonoscopies between September 2022 and March 2023 at the Toyoshima Endoscopy Clinic. Colorectal polyps were endoscopically assessed using the Japan Narrow-Band Imaging Expert Team (JNET) classification. All resected polyps were histologically examined, and the proliferative zone locations were assessed in the adenomas. RESULTS: The frequency of adenomas with a lower proliferative zone was 1.8% (44/2420) in adenomas. Among these adenomas, JNET type 1 incidence was 43.2% (19/44), which was significantly higher than that in adenomas with a normal proliferative zone. Adenomas with a lower proliferative zone were diminutive (mean size: 2.5 mm) and prone to develop in the proximal colon. CONCLUSION: Colonic adenomas with proliferative zones confined to the lower two-thirds of the crypt often appear as diminutive, hyperplastic polyps.

Classification of GIST and other benign gastric tumors based on minimally invasive surgical strategy.

PURPOSE: Gastrointestinal mesenchymal tumors (GMTs) include malignant, intermediate malignancy, and benign lesions. The aim is to propose a new surgical classification to guide the intraoperative minimally invasive surgical strategy in case of non-malignant GMTs less than 5 cm. METHODS: Primary endpoint is the creation of a classification regarding minimally invasive surgical technique for these tumors based on their gastric location. Secondary endpoint is to analyze the R0 rate and the postoperative morbidity and mortality rates. Tumors were classified in two groups based on their morphology (group A: exophytic, group B: transmural/intragastric). Each group is then divided based on the tumor location and consequently surgical technique used in subgroup: AI (whole stomach area) and AII (iuxta-cardial and pre-pyloric areas) both for the anterior and posterior gastric wall; BIa (greater curvature on the anterior and posterior wall), BIb (lesser curvature on the anterior wall); BII (iuxta-cardial and pre-pyloric area in the anterior and posterior wall, including the lesser curvature on the posterior wall). RESULTS: Forty-two patients were classified and allocated in each subgroup: 17 in AI, 2 in AII, 5 in BIa, 3 in BIb, and 15 in BII. Two postoperative Clavien-Dindo I complications (4.8%, subgroup BIa and BIb) occurred. One patient (2.4%, subgroup AI) underwent reintervention due to R0 resection. CONCLUSIONS: This classification proved to be able to classify gastric lesions based on their morphology, location, and surgical treatment, obtaining encouraging perioperative results. Further studies with wider sample of patients are required to draw definitive conclusions.

Endoscopic Diagnosis Strategy of Raspberry-Shaped Gastric Lesion in Helicobacter Pylori-Uninfected Patient.

OBJECTIVES: We aimed to clarify the endoscopic and clinicopathological features of raspberry-shaped gastric lesions (RSGLs) and to establish an endoscopic diagnostic algorithm for RSGLs. METHODS: We collected RSGLs from an endoscopic database at our hospital between May 2009 and August 2021. All RSGLs were histopathologically classified and compared based on their endoscopic and clinicopathological characteristics. RESULTS: Sixty-five RSGLs in 54 patients were classified into five histopathological types: gastric adenocarcinoma of foveolar type (GA-FV, n = 43), gastric adenocarcinoma of fundic-gland type (GA-FG, n = 2), gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM, n = 4), hyperplastic polyp (HP, n = 12), and proton pump inhibitor-related lesion (PPI-L, n = 4). All RSGLs exhibited polygonal or curved marginal crypt epithelium (MCE). GA-FV lesions had homogenously reddish (95%) and an irregular microvascular (MV) pattern (91%). GA-FG lesions were heterogeneously reddish with a submucosal tumor shape (100%) and had a regular MV pattern (50%). GA-FGM lesions were homogen+ously reddish (75%) and occasionally had a submucosal tumor shape (50%) with an irregular MV pattern (75%). HPs and PPI-Ls were homogeneously reddish (93%), with linear or dotted MCE (81%) and a regular MV pattern (100%). CONCLUSION: Our diagnostic algorithm for RSGLs constructed using endoscopic features might be useful for the endoscopic differential diagnosis of RSGLs.

Giant Hyperplastic Polyp at the Gastroesophageal Junction: A Rare Provocateur of Upper Gastrointestinal Bleeding.

Esophageal hyperplastic polyps (HPs) are a rare benign polypoidal growth most commonly resulting from gastroesophageal reflux disease (GERD). The lesion is asymptomatic in most patients unless large enough to cause luminal obstruction or gastrointestinal bleeding. The treatment of choice is endoscopic resection if it becomes symptomatic. Here, we report a case of a 51-year-old woman presenting with dyspeptic symptoms and upper gastrointestinal bleeding. An upper gastrointestinal endoscopy showed a large polyp with active oozing of blood at the gastroesophageal junction (GEJ), which was removed endoscopically after injecting adrenaline at its base. Histopathological analysis was suggestive of HPs.

Endoscopic differential diagnosis between foveolar-type gastric adenoma and gastric hyperplastic polyps in Helicobacter pylori-naïve patients.

BACKGROUND: Foveolar-type gastric adenoma (FGA) occurs in Helicobacter pylori (Hp)-naïve individuals and morphologically mimics Hp-naïve gastric hyperplastic polyp (HpN-GHP). FGA is often difficult to distinguish from HpN-GHP even by biopsy, due to its low-grade histologic atypia. We conducted a retrospective study to create an endoscopic diagnostic index. METHODS: We analyzed 51 FGAs in 41 patients and 36 HpN-GHPs in 24 patients. All lesions were photographed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). Three experts and three non-experts reviewed the WLE and WLE+NBIME images to assess six items for lesion diagnosis. We analyzed correlations between the diagnostic items and histologic features and compared the diagnostic accuracy between modalities. We created a composite diagnostic index and calculated its accuracy and consistency. RESULTS: FGAs more frequently showed the following features vs. HpN-GHPs: bright-red color (94.1% vs. 44.4%), peripheral hyperplasia (58.8% vs. 8.3%), papillary/gyrus-like microstructure (96.1% vs. 33.3%), visible capillaries (70.6% vs. 38.9%), and demarcation line (98.0% vs. 41.7%) (P < 0.05). White-zone thickening was seen only in HpN-GHPs (52.8%). Diagnostic accuracy (mean, WLE vs. WLE+NBIME) was 90.8 ± 1.1% vs. 93.5 ± 2.4% (P = 0.15) for experts and 88.5 ± 3.0% vs. 86.6 ± 3.5% (P = 0.51) for non-experts. When satisfying the four criteria (bright-red color, papillary/gyrus-like microstructure, demarcation line, and absent white-zone thickening), sensitivity and specificity for FGA were 90.2% and 94.4%, respectively, with a kappa value of ≥ 0.6 for interobserver diagnostic agreement. CONCLUSIONS: Composite diagnostic index contributes to the reproducible, accurate, preoperative differential diagnosis of FGA and HpN-GHP.

The Importance of Evaluating Serum Levels of Tumor Markers M2-PK and Inhibin A in Patients Undergoing Colonoscopy.

Despite the use of colonoscopy to detect colon cancer due to its aggressiveness, high cost, and lack of patient compliance, the use of laboratory tests with high accuracy and sensitivity, such as tumor marker M2-PK and Inhibin A is recommended and can be effective for early diagnosis and screening of patients in the early stages. We studied 46 patients admitted it the gastrointestinal ward of Amir al Momenin Hospital and 45 normal (age and sex-matched) subjects as a control group (case-control and retrospective studies). Before the colonoscopy, the level of tumor marker M2-PK in the stool sample and the serum level of Inhibin A were evaluated in patients and the control group. The level of tumor marker M2-PK was significantly higher in the group with hyperplastic polyps and colon cancer (P < .001) than in the control group. At the same time, there was no significant difference in Inhibin A level (P = .054). In the hyperplastic polyps group 73% and in the colorectal cancer group 27% had a positive immunochemical fecal occult blood (IFOBT) result, significantly higher than the control group (P < .001). Evaluation of the level of tumor marker M2-PK in the stool sample in association with the three-time iFOBT test method may be suggested as a quick and noninvasive method for screening and diagnosis of polyps and early stages of colon cancer.

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.

Three pathologic criteria for reproducible diagnosis of colonic sessile serrated lesion versus hyperplastic polyp.

Colonic SSLs are thought to predispose to ∼30% of colonic adenocarcinomas. This increased risk, compared to benign HPs, makes their distinction vitally important. However, no gold standard exists to differentiate them, and wide observer variability is reported. To better distinguish these polyps, we investigated 94 serrated polyps (53 SSLs and 41 HPs) using an easy-to-apply pathologic scoring system that combines, for the first time, three established distinguishing features: polyp morphology, location, and size. As an additional novel approach, polyp size was assessed by serrated biopsy number compared to endoscopic size. RNA expression profiling served as an additional biomarker. The considerable morphologic overlap across serrated polyps was quantitated for the first time. Interobserver variability was assessed by 8 expert gastrointestinal pathologists. By ROC analysis, polyp size by biopsy number performed best, followed by polyp location and morphology (areas under the curves [AUCs] = 85.9%, 81.2%, and 65.9%, respectively). Optimal discrimination combined all 3 features (AUC = 92.9%). For polyp size, the biopsy number proved superior to endoscopic size (AUC = 85.9% versus 55.2%, P = .001). Interobserver variability analysis yielded the highest reported Fleiss and Kappa statistics (0.879) and percent agreement (96.8%), showing great promise toward improved diagnosis. The proposed 3-criteria pathologic system, combining size by biopsy number, location, and morphology, yields an improved, easy-to-use, and highly reproducible diagnostic approach for differentiating SSLs and HPs.

Autoimmune gastritis with a gastric hamartomatous inverted polyp and two hyperplastic polyps: a case report.

We report an unusual case of autoimmune gastritis (AIG) complicated with a submucosal tumor (SMT) and two pedunculated polyps in a 60-year-old man. The patient was admitted for epigastric distention, heartburn, and anorexia. Endoscopy showed an SMT in the fundus, two pedunculated polyps in the body, and markedly atrophic mucosa of the body and fundus. The SMT, measuring 20 mm in diameter, was resected by endoscopic submucosal dissection and histologically diagnosed as a gastric hamartomatous inverted polyp (GHIP), which is characterized by submucosal glandular proliferation, cystic dilatation, and calcification. The gland structures consisted of foveolar cells and pseudopyloric or mucous-neck cell types. The two pedunculated polyps that were resected by endoscopic mucosal resection were histologically diagnosed as hyperplastic polyps, which are characterized by hyperplastic foveolar glands with pseudopyloric or mucous-neck glands in the inflamed stroma in the mucosa, which consisted of almost the same types of lining cells as the GHIP in the fundus. Findings may indicate the relationship between GHIP, hyperplastic polyp, and AIG. We highlight considering GHIP as a differential diagnosis for an SMT in patients with AIG.

Sporadic hyperplastic polyp associated with above-average risk of developing metachronous colorectal cancer.

Post-colonoscopy surveillance interval for colorectal polyps depends on the size, number, and pathological classification of removed polyps. The risk of sporadic hyperplastic polyps (HPs) for developing colorectal adenocarcinoma remains debatable due to limited data. We aimed to evaluate the risk of metachronous colorectal cancer (CRC) in patients with sporadic HPs. A total of 249 patients with historical HP(s) diagnosed in 2003 were included as the disease group, and 393 patients without any polyp as the control group. All historical HPs were reclassified into SSA or true HP based on the recent 2010 and 2019 World Health Organization (WHO) criteria. Polyp size was measured under light microscope. Patients developed CRC were identified from the Tumor Registry database. Each tumor was tested for DNA mismatch repair proteins (MMR) by immunohistochemistry. Results showed that 21 (8%) and 48 (19%) historical HPs were reclassified as SSAs based on the 2010 and 2019 WHO criteria, respectively. The mean polyp size of SSAs (6.7 mm) was significantly larger than HPs (3.3 mm) (P<0.0001). For polyp size ≥5 mm, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing SSA was 90%, 90%, 46%, and 99%, respectively. Left-sided polyps with size <5 mm were 100% of HPs. Five of 249 (2%) patients developed metachronous CRC during the 14-year follow-up from 2003 to 2017, including 2 of 21 (9.5%) patients with SSA diagnosed at intervals of 2.5 and 7 years, and 3 of 228 (1.3%) patients with HP(s) at 7, 10.3, and 11.9 years. Two of 5 cancers showed MMR deficiency with concurrent loss of MLH1/PMS2. Based on the 2019 WHO criteria, the rate of developing metachronous CRC in patients with SSA (P=0.0116) and HP (P=0.0384) was significantly higher than the control group, and no significant difference was observed between patients with SSA and with HP (P=0.241) in this cohort. Patients with either SSA or HP also had higher risk of CRC than average-risk US population (P=0.0002 and 0.0001, respectively). Our data add a new line of evidence that patients with sporadic HP are associated with above-average risk of developing metachronous CRC. Post-polypectomy surveillance for sporadic HP may be adjusted in future practice given the low but increased risk of developing CRC.

Image-enhanced endoscopy for real-time differentiation between hyperplastic and fundic gland polyps in the stomach.

BACKGROUND: Fundic gland polyps (FGP) of stomach are benign, while some hyperplastic polyps (HP) may harbor dysplasia or malignancy. Conventional white light endoscopy (WLE) cannot reliably distinguish FGP from HP. We investigated the role of image-enhanced endoscopy in differentiating FGP from HP. METHODS: Patients with gastric polyps were recruited prospectively. The characteristics of the polyps were assessed using WLE and magnification narrow band imaging (mNBI). The microsurface, intervening space (IS), and microvascular (V) features of polyps were evaluated on mNBI. The pattern characteristic of FGP and HP were determined. Histopathology of polyps was the gold standard for diagnosis. Finally, in the validation phase, five endoscopists applied the characteristic features identified in this study to predict the type of gastric polyp and their performance was assessed. RESULTS: Forty-five patients with a total of 70 gastric polyps (HP-46, FGP-24) were included in this study. On mNBI, the pattern characteristic of HP included peripheral curved type of white structures forming large circular/villous loops (microsurface), enlarged intervening space, and microvessels appearing as dark patches in the intervening space (p<0.001 vs. FGP). These were noted in 95.7% HP. In contrast, 95.8% FGP had a pattern characterized by dotted/elliptical/tubular white structures (microsurface), normal width of intervening space, and microvessels surrounding the white structures in a network pattern. This IS-V pattern classification had an accuracy of >90% in the validation phase with intra-class correlation coefficient of 0.95. The accuracy of mNBI was higher than WLE (97.1% vs. 67%) in predicting the type of gastric polyp. CONCLUSIONS: Image-enhanced endoscopy with mNBI (IS-V pattern) performs very well in differentiating HP from FGP.

Gastric Hyperplastic Polyp Causing Upper Gastrointestinal Hemorrhage and Severe Anemia in a Dog.

An 11-year-old castrated male Shih Tzu was referred for lethargy and melena. The hematocrit level was 18.8% (normal range: 36-56%), indicating severe anemia. Abdominal ultrasound revealed a round-to-oval-shaped mass in the stomach. Computed tomography (CT) revealed an intraluminal mass (17 × 12 × 15 mm) cranial to the pyloric antrum. After obtaining informed consent from the owner, exploratory laparotomy and subsequent gastrostomy were performed, showing an ulcerated mass potentially responsible for the severe anemia. A lump of hair was firmly attached to the ulcerated surface of the mass. After complete removal of the mass, the anemia resolved spontaneously. Histological examination revealed that the mass was a gastric hyperplastic polyp. At the 6-month follow-up, the dog was healthy with a normal hematocrit level. Gastric hyperplastic polyps are tumor-like lesions arising from the mucosal surface of the stomach, and projecting into the lumen. They can appear in any part of the stomach, and are usually found incidentally during gastric endoscopy or necropsy. The clinical signs include chronic occult blood loss, abdominal pain, and gastric tract obstruction. Gastric polyps causing acute blood loss anemia have rarely been reported in human medicine. To our knowledge, this is the first report describing a gastric hyperplastic polyp that caused severe anemia because of acute blood loss in a dog.

Morphological and molecular characterization of colorectal sessile serrated lesions with dysplasia.

In sessile serrated lesions (SSLs) with adenomatous dysplasia, the dysplastic component and the serrated component without dysplasia should be considered as part of the same lesion, classified as SSL with dysplasia. However, some of these lesions may actually represent collisions between a serrated polyp and a conventional adenoma. Further supporting the "collision theory", conventional adenomatous dysplasia may be found in association with hyperplastic polyps (HPs). In order to determine the molecular and biological landscape of conventional type dysplasia in serrated lesions, we collected 17 cases of colorectal serrated lesions with adenomatous dysplasia, classifying them as SSL with dysplasia (n = 10) or as mixed lesions comprising a HP component and a conventional adenomatous component (n = 7). We characterized the dysplastic and the non-dysplastic component of each lesion, after microdissection, through the targeted mutational analysis of 11 commonly altered genes in colorectal cancer (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53). We also characterized MMR and p53 status by immunohistochemistry. Overall, 14/17 (82.4 %) cases harbored a mutation in at least one of the two components. The most altered genes were BRAF in 10/17 (58.8 %) cases, APC in 2/17 (11.8 %) and TP53 in 4/17 (23.5 %). Among the SSL with dysplasia, the mutational profile was concordant between the two components in 7/10 (70 %) cases, while among the mixed lesions, the mutational profile was concordant in 1/7 (14.3 %). In all but two cases of SSL with dysplasia, MMR status was concordant between the two components of the serrated lesions. Our findings suggest that adenomatous dysplasia may develop in SSL as part of the serrated lesion, even if some SSL with dysplasia may actually be collision lesions. On the other hand, the polyps that are morphologically classifiable as mixed lesions composed of a HP and a conventional adenomatous component are more likely to be collision lesions.