Collagenous gastritis: clinical features, histologic correlates and unanswered questions.

Collagenous gastritis (CG) is a rare gastrointestinal disorder characterized by subepithelial collagen deposition and lamina propria inflammation. Despite its first description over four decades ago, the pathogenesis remains unclear, with no standardized pathologic criteria/classification, treatment or established prognosis. A systematic PubMed search identified all English-language case reports, series and observational studies describing CG.

Consensus Guideline for the Management of Patients with Appendiceal Tumors, Part 2: Appendiceal Tumors with Peritoneal Involvement.

Background: Appendiceal tumors comprise a heterogeneous group of tumors that frequently disseminate to the peritoneum. Management of appendiceal tumors is lacking high quality data given their rarity and heterogeneity. In general, appendiceal tumor treatment is extrapolated in part from colorectal cancer or pooled studies, without definitive evidence of disease-specific benefit.

Consensus guideline for the management of patients with appendiceal tumors, part 2: Appendiceal tumors with peritoneal involvement.

Background: Appendiceal tumors comprise a heterogeneous group of tumors that frequently disseminate to the peritoneum. Management of appendiceal tumors is lacking high-quality data given their rarity and heterogeneity. In general, appendiceal tumor treatment is extrapolated in part from colorectal cancer or pooled studies, without definitive evidence of disease-specific benefit.

Clinicopathologic Features of Untreated Colorectal Cancer with Acellular Mucin-Only Lymph Nodes.

Lymph nodes (LNs) containing only acellular mucin are considered negative for metastasis in treated colorectal cancers (CRCs). However, no data exist on how to stage these LNs in untreated CRCs. We collected 63 untreated CRC cases with LNs containing only acellular mucin from 27 US institutions and 23 additional cases from the Dutch Nationwide Pathology Databank.

Genetic Mutations and Small Bowel Ulcerating Disease: Role in Diagnosis?

Purpose Of Review: This review examines the role of genetic variations in the pathogenesis of small bowel (SB) ulcers associated with Crohn's disease (CD), NSAID enteropathy, and Cryptogenic Multifocal Ulcerous Stenosing Enteritis (CMUSE)/Chronic Non-Specific Ulcers of the Small Intestine (CNSU), aiming to address current diagnostic challenges.

Recent Findings: Advances in molecular genetics have revealed significant genetic contributors to SB ulceration. In CD, the NOD2 gene on chromosome 16 and several additional risk variants identified through genome-wide association studies (GWAS)-with key insights from the International Inflammatory Bowel Disease Genetics Consortium-have enhanced our understanding of the pathobiology of the disease.

Screening at the scope: enhancing the role of pathologists in diagnosing gastrointestinal polyposis syndromes.

Only a minority of patients at high likelihood of a gastrointestinal polyposis syndrome (GPS) are appropriately referred for workup. This proof-of-concept study evaluates a GPS screening rubric based exclusively on information in prior pathology reports and intended to facilitate pathologist engagement in GPS screening and referral. We sought to (1) identify patients who would benefit from further GPS workup, (2) assign a probable polyposis syndrome category (adenomatous, hamartomatous, serrated, or mixed), and (3) suggest a specific syndrome, such as familial adenomatous polyposis, whenever possible.

Augmented reality microscopy to bridge trust between AI and pathologists.

Diagnostic certainty is the cornerstone of modern medicine and critical for maximal treatment benefit. When evaluating biomarker expression by immunohistochemistry (IHC), however, pathologists are hindered by complex scoring methodologies, unique positivity cut-offs and subjective staining interpretation. Artificial intelligence (AI) can potentially eliminate diagnostic uncertainty, especially when AI "trustworthiness" is proven by expert pathologists in the context of real-world clinical practice.

Diagnostic Challenges due to a Germline Missense MSH2 Variant in a Patient With Immunotherapy-Responsive Locally Advanced Rectal Adenocarcinoma.

Background: Rapid and accurate identification of mismatch repair (MMR) deficiency and Lynch syndrome is critical in the prognostication and clinical management of patients with colorectal carcinoma.

Case Description: We describe here a young woman who developed a locally aggressive rectal adenocarcinoma with intact MMR protein expression by immunohistochemistry and absence of histologic evidence of MMR deficiency-associated increased tumoral immune response. Germline DNA-targeted sequencing identified MSH2 variant p.

MEN1/DAXX/ATRX mutations enhance progression-free survival in gastroenteropancreatic neuroendocrine tumors treated with peptide receptor radionuclide therapy.

Pre-clinical data suggest that mutations in the MEN1, DAXX, and/or ATRX genes may potentially increase radiation efficacy in cancer cells. Herein, we explore the association between response to peptide receptor radionuclide therapy (PRRT) and those mutations in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). We analyzed tissue-based next generation sequencing (NGS) assay results and clinicopathologic data from 28 patients with GEP-NETs treated with PRRT.

Follow-up biopsies in gastrointestinal immune checkpoint inhibitor toxicity may show markedly different inflammatory patterns than initial injury.

Colitis is a common manifestation of immune checkpoint inhibitor (ICI) toxicity and can present with varied histologic patterns of inflammation, some of which have been shown to be associated with specific ICI drug types. Although the histologic features of ICI colitis seen at the time of diagnosis have been described, there have been few reports following these patients over time. We evaluated initial and follow-up biopsies in 30 patients with ICI colitis and found that 37% of patients developed a different pattern of injury on follow-up biopsy compared to the initial biopsy.

A novel telomere biology disease-associated gastritis identified through a whole exome sequencing-driven approach.

A whole exome sequencing (WES)-driven approach to uncover the etiology of unexplained inflammatory gastritides has been underutilized by surgical pathologists. Here, we discovered the pathobiology of an unusual chronic atrophic gastritis in two unrelated patients using this approach. The gastric biopsies were notable for an unusual pattern of gastritis with persistent dense inflammation, loss of both parietal and neuroendocrine cells in the oxyntic mucosa, and sparing of the antral mucosa.

Single center outcomes from parenchymal-sparing resections and microwave ablations for neuroendocrine tumor liver metastases.

Background: Reported outcomes after surgical debulking in patients with advanced neuroendocrine tumor liver metastases (NETLM) are sparse.

Methods: NETLM patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function, complications, symptom response, and progression-free survival were examined.

A tumor microenvironment-based classification of gastric cancer for more effective diagnosis and treatment.

With approximately one million diagnosed cases and over 700,000 deaths recorded annually, gastric cancer (GC) is the third most common cause of cancer-related deaths worldwide. GC is a heterogeneous tumor. Thus, optimal management requires biomarkers of prognosis, treatment selection, and treatment response.

Endoscopic Ultrasound Predicts Risk of Occult Intra-Abdominal Metastases in Localized Gastric Cancer: A Validation Study.

Background: In gastric cancer (GC) patients without imaging evidence of distant metastasis, diagnostic staging laparoscopy (DSL) is recommended to detect radiographically occult peritoneal metastasis (M1). DSL carries a risk for morbidity and its cost-effectiveness is unclear. Use of endoscopic ultrasound (EUS) to improve patient selection for DSL has been proposed but not validated.

All Together Now: Standardization of Nomenclature for Neuroendocrine Neoplasms across Multiple Organs.

Neuroendocrine neoplasms (NENs) span virtually all organ systems and exhibit a broad spectrum of behavior, from indolent to highly aggressive. Historically, nomenclature and grading practices have varied widely across, and even within, organ systems. However, certain core features are recapitulated across anatomic sites, including characteristic morphology and the crucial role of proliferative activity in prognostication.

The histological spectrum of ARB-induced gastritis.

Aims: Olmesartan, an angiotensin receptor blocker (ARB) used for hypertension management, is known to cause a sprue-like enteropathy in a subset of patients. Rare cases of gastritis occurring with ARB use have also been reported, but the histological features of ARB-induced gastritis and the response to drug cessation have not been examined in a dedicated case-series.

Methods And Results: Cases of suspected ARB-induced gastritis were identified from the pathology archives of four institutions.

Serum Cytomegalovirus Polymerase Chain Reaction Test Is a Valuable Negative Predictor of Infection in Acute Severe Ulcerative Colitis.

Background: Diagnosis of cytomegalovirus (CMV) colitis in the setting of severe ulcerative colitis (UC) remains a clinical challenge. This study aimed to determine the utility of serum CMV polymerase chain reaction (PCR) as a non-invasive test for the diagnosis of CMV superinfection in patients hospitalized with UC.

Methods: This retrospective study included consecutive admitted patients with UC who had serum testing for CMV completed as part of standard hospital procedure and CMV colitis diagnosed by expert pathologists.

Measuring the Submucosal Depth of Invasion in Endoscopic Mucosal Resections for Barrett-associated Adenocarcinoma: Practical Issues and Relevance for the Decision for Esophagectomy.

Context.—: Endoscopic mucosal resection (EMR) has made it possible for Barrett esophagus patients with superficial cancers to be treated without esophagectomy. Recent guidelines recommend measuring depth of invasion (DOI) in submucosal cancers based on reports that in low-risk cancers, submucosal invasion 500 μm or less is associated with low nodal metastasis rates.

Recurrent Loss of Heterozygosity in Pancreatic Neuroendocrine Tumors.

Chromosomal aneuploidies are prognostic markers across a wide variety of tumor types, and recent literature suggests that pancreatic neuroendocrine tumors are no different. In this study 214 patients with grade 1, 2, or 3 pancreatic neuroendocrine tumors had their tissue examined for chromosomal copy number alterations using next-generation sequencing. Univariate and multivariate statistical analyses were performed with all-cause mortality and disease-specific mortality as the end comparators.

Epigenetic Dysregulation of 5-hydroxymethylcytosine in Well-Differentiated Pancreatic Neuroendocrine Tumors.

Dysregulation of epigenetic mechanisms, reflected by loss of expression of 5-hydroxymethylcytosine (5-hmC) is being increasingly recognized as a marker of aggressive behavior in several neoplasms; however, the role of such epigenetic modifiers in pancreatic neuroendocrine tumors (PanNETs) has not been studied. Annotated cohort of 60 PanNETs was evaluated for 5-hmC expression using immunohistochemistry. Univariable and multivariable analyses were performed.

Hypermucinous, Goblet Cell-Deficient and Crypt Cell Dysplasias in Inflammatory Bowel Disease are Often Associated with Flat/Invisible Endoscopic Appearance and Advanced Neoplasia on Follow-Up.

Background And Aims: Several different types of non-conventional dysplasia have been recently described in inflammatory bowel disease [IBD]. Hypermucinous, goblet cell-deficient and crypt cell dysplasias have received most attention, but there is limited information regarding their clinicopathological features and clinical outcomes.

Methods: A total of 126 cases of hypermucinous [n = 55], goblet cell-deficient [n = 26] and crypt cell [n = 45] dysplasias from 97 IBD patients were collected from seven different institutions and analysed.

Sunitinib-Loaded Chondroitin Sulfate Hydrogels as a Novel Drug-Delivery Mechanism for the Treatment of Pancreatic Neuroendocrine Tumors.

Background: Pancreatic neuroendocrine tumors (PanNETs) are increasingly common. Experts debate whether small tumors should be resected. Tumor destruction via injection of cytotoxic agents could offer a minimal invasive approach to this controversy.