New entity of adult ultra-short coeliac disease: the first international cohort and case-control study.

BACKGROUND: Ultra-short coeliac disease (USCD) is defined as villous atrophy only present in the duodenal bulb (D1) with concurrent positive coeliac serology. We present the first, multicentre, international study of patients with USCD. METHODS: Patients with USCD were identified from 10 tertiary hospitals (6 from Europe, 2 from Asia, 1 from North America and 1 from Australasia) and compared with age-matched and sex-matched patients with conventional coeliac disease. FINDINGS: Patients with USCD (n=137, median age 27 years, IQR 21-43 years; 73% female) were younger than those with conventional coeliac disease (27 vs 38 years, respectively, p<0.001). Immunoglobulin A-tissue transglutaminase (IgA-tTG) titres at index gastroscopy were lower in patients with USCD versus conventional coeliac disease (1.8×upper limit of normal (ULN) (IQR 1.1-5.9) vs 12.6×ULN (IQR 3.3-18.3), p<0.001).Patients with USCD had the same number of symptoms overall (median 3 (IQR 2-4) vs 3 (IQR 1-4), p=0.875). Patients with USCD experienced less iron deficiency (41.8% vs 22.4%, p=0.006).Both USCD and conventional coeliac disease had the same intraepithelial lymphocytes immunophenotype staining pattern; positive for CD3 and CD8, but not CD4.At follow-up having commenced a gluten-free diet (GFD) (median of 1181 days IQR: 440-2160 days) both USCD and the age-matched and sex-matched controls experienced a similar reduction in IgA-tTG titres (0.5 ULN (IQR 0.2-1.4) vs 0.7 ULN (IQR 0.2-2.6), p=0.312). 95.7% of patients with USCD reported a clinical improvement in their symptoms. INTERPRETATION: Patients with USCD are younger, have a similar symptomatic burden and benefit from a GFD. This study endorses the recommendation of D1 sampling as part of the endoscopic coeliac disease diagnostic workup.

A Clinicopathologic Comparison Between Early-Onset and Late-Onset Small Bowel Adenocarcinoma: A Multicenter International Study.

INTRODUCTION: Early-onset small bowel adenocarcinoma (EO-SBA) is a rare and poorly characterized entity. METHODS: This retrospective study conducted on an international multicenter cohort of 208 patients with SBA aimed at comparing clinicopathologic features of EO-SBA (age younger than 50 years at SBA diagnosis) and late-onset SBA (age 50 years or older at SBA diagnosis). RESULTS: The presence of predisposing pathologic conditions was significantly more common in the EO-SBA group compared with that in the late-onset SBA group ( P = 0.003, Fisher exact test; relative risk: 1.50, 95% confidence interval: 1.20-1.86). This difference is mainly due to the significantly higher prevalence of celiac disease among patients with EO-SBA. DISCUSSION: EO-SBA is strongly associated with predisposing conditions, particularly with celiac disease, highlighting the importance of routine screening for celiac disease in patients with EO-SBA.

IDH1-mutated Crohn's disease-associated small bowel adenocarcinomas: Distinctive pathological features and association with MGMT methylation and serrated-type dysplasia.

AIMS: Patients with Crohn's disease (CrD) have an elevated risk for the development of small bowel adenocarcinomas (SBAs). Actionable isocitrate dehydrogenase 1 (IDH1) mutations have been reported to be more frequent in CrD-SBAs than in sporadic SBAs. The present study aimed to investigate the clinicopathological and immunophenotypical features, as well as methylation profiles, of IDH1-mutated CrD-SBAs. METHODS AND RESULTS: An international multicentre series of surgically resected CrD-SBAs was tested for IDH1 mutation. Clinicopathological features, immunophenotypical marker expression and O6-methylguanine-DNA methyltransferase (MGMT) and long interspersed nuclear element-1 (LINE-1) methylation were compared between IDH1-mutated and IDH1 wild-type CrD-SBAs. Ten (20%) of the 49 CrD-SBAs examined harboured an IDH1 mutation and all the mutated cancers harboured the R132C variant. Compared to IDH1 wild-type cases, IDH1-mutated CrD-SBAs showed significantly lower rates of cytokeratin 7 expression (P = 0.005) and higher rates of p53 overexpression (P = 0.012) and MGMT methylation (P = 0.012). All three dysplastic growths associated with IDH1-mutated SBAs harboured the same IDH1 variant (R132C) of the corresponding invasive cancer, and all were of non-conventional subtype (two serrated dysplastic lesions and one goblet cell-deficient dysplasia). In particular, non-conventional serrated dysplasia was significantly associated with IDH1-mutated CrD-SBAs (P = 0.029). No significant cancer-specific survival difference between IDH1-mutated CrD-SBA patients and IDH1 wild-type CrD-SBA patients was found (hazard ratio = 0.55, 95% confidence interval = 0.16-1.89; P = 0.313). CONCLUSIONS: IDH1-mutated CrD-SBAs, which represent approximately one-fifth of total cases, are characterised by distinctive immunophenotypical features and methylation profiles, with potential therapeutic implications. Moreover, IDH1-mutated non-conventional, serrated dysplasia is likely to represent a precursor lesion to such CrD-SBAs.

Medullary carcinomas of the nonampullary small intestine: association with coeliac disease, mismatch repair deficiency, PD-L1 expression, and favourable prognosis.

AIM: Gastrointestinal medullary carcinoma is a rare histologic subtype of adenocarcinoma. As nonampullary small bowel medullary carcinomas (SB-MCs) are poorly characterized, we aimed to analyse their clinicopathologic and immunohistochemical features and to compare them with nonmedullary small bowel adenocarcinomas (NM-SBAs). METHODS AND RESULTS: Surgically resected SBAs collected through the Small Bowel Cancer Italian Consortium were classified as SB-MCs (carcinomas with ≥50% of tumour fulfilling the typical histologic criteria of MC) or NM-SBAs. Immunohistochemistry for cytokeratin (CK)7, CK20, CDX2, programmed death-ligand 1 (PD-L1) and mismatch repair proteins was performed in both SB-MCs and NM-SBAs. SB-MCs were also tested for CK8/18, synaptophysin, SMARCB1, SMARCA2, SMARCA4, and ARID1A and for Epstein-Barr virus (EBV)-encoded RNAs by in-situ hybridization. MLH1 promoter methylation status was evaluated in MLH1-deficient cases. Eleven SB-MCs and 149 NM-SBAs were identified. One (9%) SB-MC was EBV-positive, while 10 (91%) harboured mismatch repair deficiency (dMMR). MLH1 promoter hypermethylation was found in all eight dMMR SB-MCs tested. Switch/sucrose nonfermentable deficiency was seen in two (18%) SB-MCs, both with isolated loss of ARID1A. Compared with NM-SBAs, SB-MCs exhibited an association with coeliac disease (P < 0.001), higher rates of dMMR (P < 0.001), and PD-L1 positivity by both tumour proportion score and combined positive score (P < 0.001 for both), and a lower rate of CK20 expression (P = 0.024). Survival analysis revealed a better prognosis of SB-MC patients compared to NM-SBA cases (P = 0.02). CONCLUSION: SB-MCs represent a distinct histologic subtype, with peculiar features compared to NM-SBAs, including association with coeliac disease, dMMR, PD-L1 expression, and better prognosis.

Histopathology of intestinal villi in neonatal and paediatric age: main features with clinical correlation - Part I.

The neonatal and paediatric spectrum of small bowel disorders encompass a wide variety of conditions, ranging from food allergies to life-threatening surgical emergencies or life-long medical conditions and, as such, it comes with a whole set of diagnostic challenges for the non-paediatric pathologist. Histologic examination is a cornerstone of diagnosis in a large number of diseases and may still provide important diagnostic clues in the appropriate clinical context. In this review, divided in two sections, we aim to provide a comprehensive histopathological summary of paediatric small bowel alteration and their differential diagnoses with a reference to the main clinical aspects required for appropriate interpretation. Specifically, in this first part, we describe congenital and metabolic disorders, intestinal lymphangiectasia, immunodeficiencies, GVHD, and necrotising enterocolitis.

Histopathology of intestinal villi in neonatal and paediatric age: main features with clinical correlation - Part II.

In this paper, we will continue the description of histological findings of infantile and paediatric small bowel alterations with the main clinical pictures and differential diagnosis. We emphasise once again the need to evaluate the biopsies in an adequate clinical contest and with a systematic approach, including epithelial alterations, lamina propria changes, mucosal architecture, and the distribution of inflammation, together with other morphological signs more specific of certain diseases. We describe the histological findings of coeliac and Crohn's disease, gastrointestinal food allergic diseases, Langerhans cell histiocytosis, nutritional deficiencies and infections. Finally, we suggest the principal issues in the drafting the pathological report for appropriate interpretation and usefulness in clinical practice.

Very Early Onset-IBD: evidence for the need of a multidisciplinary approach.

Very early onset inflammatory bowel disease (VEO-IBD) represents approximately 25% of cases of IBD-like colitis occurring during childhood and, by definition, it is characterized by an onset prior to 6 years of age. This subgroup of patients presents significant differences from IBD occurring in older children and in adults, including a more severe clinical course, a reduced responsiveness to conventional IBD therapy, and a greater proportion of cases featuring an underlying monogenic disorder. Histological findings from gastro-intestinal (GI) biopsies are characterized by an IBD-like, apoptotic or enterocolitis-like pattern, complicating the differential diagnosis with other pediatric diseases involving GI tract. Moreover, individuals with monogenic disorders may develop significant comorbidities, such as primary immunodeficiency (PID), impacting treatment options. Without an appropriate diagnosis, the clinical course of VEO-IBD has greater potential for escalated treatment regimens involving extensive surgery, more intensive medical therapies and, even more important, inadequate recognition of underlying monogenic defect that may lead to inappropriate (sometimes fatal) therapy. For these reasons, an adequate context leading to an appropriate diagnosis is imperative, calling for a close collaboration between pediatricians, pathologists, geneticists, and immunologists.

Prognostic Role of Mismatch Repair Status, Histotype and High-Risk Pathologic Features in Stage II Small Bowel Adenocarcinomas.

BACKGROUND: Small bowel adenocarcinoma is a relatively rare cancer, often diagnosed in an advanced stage. In localized and resectable disease, surgery alone or in combination with adjuvant chemotherapy is the mainstay of treatment. In the recently published National Comprehensive Cancer Network Clinical Practice guidelines, criteria for selecting patients with stage II small bowel adenocarcinoma to receive adjuvant chemotherapy are provided, and they are mainly extrapolated from studies on colorectal cancer. PATIENTS AND METHODS: In the present study, we aimed to verify whether mismatch repair deficiency phenotype, high-risk pathologic features (including T4, positive resection margins and a low number of lymph nodes harvested), as well as tumor histologic subtype, were associated with cancer-specific survival in 66 stage II non-ampullary small bowel adenocarcinoma patients, collected through the Small Bowel Cancer Italian Consortium. A central histopathology review was performed. Mismatch repair deficiency was tested by immunohistochemistry for MLH1, MSH2, MSH6 and PMS2, and confirmed by polymerase chain reaction for microsatellite instability. RESULTS: We identified mismatch repair deficiency, glandular/medullary histologic subtype, and celiac disease as significant predictors of favorable cancer-specific survival using univariable analysis with retained significance in bivariable models adjusted for pT stage. Among the high-risk features, only T4 showed a significant association with an increased risk of death; however, its prognostic value was not independent of mismatch repair status. CONCLUSIONS: Mismatch repair protein expression, histologic subtype, association with celiac disease, and, in the mismatch repair proficient subset only, T stage, may help identify patients who may benefit from adjuvant chemotherapy.

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.

Correction: PD-L1 in small bowel adenocarcinoma is associated with etiology and tumor-infiltrating lymphocytes, in addition to microsatellite instability.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

PD-L1 in small bowel adenocarcinoma is associated with etiology and tumor-infiltrating lymphocytes, in addition to microsatellite instability.

Small bowel adenocarcinomas (SBAs) are often associated with poor prognosis and have limited therapeutic options. Programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway blockade is an effective treatment in many microsatellite instability-high (MSI-H) solid tumors. We aimed at investigating PD-L1 and PD-1 expression in non-hereditary, non-ampullary SBAs, associated with celiac disease (CeD), Crohn's disease (CrD), or sporadic, recruited through the Small Bowel Cancer Italian Consortium. We assessed PD-L1 and PD-1 by immunohistochemistry in a series of 121 surgically resected SBAs, including 34 CeD-SBAs, 49 CrD-SBAs, and 38 sporadic SBAs. PD-L1 and PD-1 expression was correlated with several clinico-pathological features, such as the etiology, microsatellite instability status, and tumor-infiltrating lymphocyte (TIL) density. The prevalence of PD-L1 positivity according to combined positive score (CPS) was 26% in the whole cohort of SBAs, with significantly (p = 0.001) higher percentage (35%) in both CeD-SBAs and CrD-SBAs in comparison with sporadic SBAs (5%). CPS ≥ 1 SBAs were significantly (p = 0.013) more frequent in MSI-H cases (41%) than in non-MSI-H ones (18%); however, 15 CPS ≥ 1 microsatellite stable SBAs were also identified. CPS ≥ 1 SBAs showed higher TIL and PD-1+ immune cell density, more frequently medullary histotype, as well as a better outcome in comparison with CPS < 1 cases. This study demonstrates an increased proportion of PD-L1+ cases in both CeD-SBAs and CrD-SBAs in comparison with sporadic SBAs. In addition, the identification of a subset of PD-L1+ microsatellite stable SBAs supports the need to ascertain additional biomarkers of response to immune checkpoint inhibitors along with MSI-H.

Celiac disease: histology-differential diagnosis-complications. A practical approach.

Celiac disease is a multi-factorial chronic inflammatory intestinal disease, characterized by malabsorption resulting from mucosal injury after ingestion of wheat gluten or related rye and barley proteins. Inappropriate T-cell-mediated immune response against ingested gluten in genetically predisposed people, leads to characteristic histological lesions, as villous atrophy and intraepithelial lymphocytosis. Nevertheless, celiac disease is a comprehensive diagnosis with clinical, serological and genetic characteristics integrated with histological features. Biopsy of duodenal mucosa remains the gold standard in the diagnosis of celiac disease with the recognition of the spectrum of histological changes and classification of mucosa damage based on updated Corazza-Villanacci system. Appropriate differential diagnosis evaluation and clinical context also for the diagnosis of complications is, moreover, needed for correct histological features interpretation and clinical management.

Prognostic and Predictive Roles of HER2 Status in Non-Breast and Non-Gastroesophageal Carcinomas.

The oncogene ERBB2, also known as HER2 or c-ERB2, is located on chromosome 17 (q12). It encodes a tyrosine kinase receptor, the human epidermal growth factor receptor 2 (HER2), involved in neoplastic proliferation, tumor angiogenesis, and invasiveness. Over the past years, the introduction of various anti-HER2 therapies has significantly improved outcomes for patients with HER2-positive breast and gastroesophageal carcinomas. More recently, the introduction of a new antibody-drug conjugate, that is trastuzumab deruxtecan, expanded the therapeutic options to low-HER2 breast and gastroesophageal tumors. HER2 protein overexpression is investigated using immunohistochemistry, gene amplification using fluorescence in situ hybridization, and gene mutation using next-generation sequencing. This review evaluated the predictive and prognostic role of HER2 status in various types of epithelial malignant cancers beyond breast and gastroesophageal cancers. We critically analyzed the key published studies, focusing on utilized scoring systems and assays used, and analyzed clinical parameters and therapeutic approaches. Although the evidence about prognostic and predictive roles of HER2 in carcinomas other than breast and gastroesophageal has been widely increasing over the last decade, it still remains investigational, revealing a tumor site-related prognostic and predictive value of the different types of HER2 alterations. However, standardized and validated scoring system assays have not been well-established for many organs.

Systematic review: Clinical phenotypes, histopathological features and prognosis of enteropathy due to angiotensin II receptor blockers.

BACKGROUND: Although enteropathy due to angiotensin II receptor blockers (ARBs) has been known for over 10 years, clinicians' awareness of this condition is still low. AIMS: To systematically review the literature about clinical phenotypes, distribution of mucosal changes throughout the gastrointestinal tract and prognosis of enteropathy due to ARBs. METHODS: According to PRISMA guidelines, we searched PubMed and Embase for relevant articles up to November 6, 2023. We included full-text papers, letters, case reports and case series describing enteropathy due to ARBs. Patients were classified into subgroups based on endoscopic and histological findings of different regions of the gastrointestinal tract. The protocol was registered with Open Science Framework (https://doi.org/10.17605/OSF.IO/TK67C). RESULTS: We included 94 articles reporting 183 cases (101 female, mean age at diagnosis 69 ± 10 years). The clinical picture at diagnosis was characterised by severe diarrhoea (97%) and weight loss (84%, median -13 kg), leading to hospital admission in 167 (95%) patients. Olmesartan (90%) was most frequently implicated. Villous atrophy (VA) was reported in 164/183 (89%) patients. One hundred and nine had only VA, 12 had pan-gastrointestinal involvement, 23 had VA and gastric involvement and 19 had VA and colon involvement (predominantly microscopic colitis). Outcomes were reported for 178/183 (97%) patients, who all recovered clinically on ARBs withdrawal. Histological recovery occurred in all 96 patients with VA at baseline who underwent follow-up duodenal biopsy. CONCLUSIONS: Enteropathy due to ARBs is characterised by severe malabsorption often requiring hospital admission and can involve the entire gastrointestinal tract. Clinician awareness can lead to prompt diagnosis and excellent prognosis.

A small bowel adenocarcinoma harboring a DDR2 mutation in a celiac patient.

We present the case of a 62-year-old man with a history of celiac disease and IgA deficiency, following a strict gluten-free diet that was admitted to our hospital for recurrent abdominal pain, fatigue and melena. Esophagogastroduodenoscopy and colonoscopy with biopsies were normal. A video-capsule endoscopy was performed and revealed a sub-stenosing, vegetating, and bleeding lesion in the first jejunal loop. He underwent laparotomic surgery with resection of the involved segment with loco-regional lymphadenectomy. The pathological report described a poorly differentiated adenocarcinoma of the jejunum, stage IIIA (pT3pN1). Analysis of next-generation sequencing (NGS) of DNA on the surgical sample revealed a likely pathogenetic variant in exon 15 of the DDR2 gene (c.2003G > A) and a TP53 non-frame-shift deletion (c.585_602del). Considering the risk of recurrence, he was candidate to 6 months of adjuvant chemotherapy with platinum salt and fluoropyrimidine. Thirty-eight months after the diagnosis, the patient is still disease free and in good clinical condition. This is the first described case of SBA with DDR2 mutation. Considering the limited therapeutic options beyond surgery for SBA, molecular analyses could become promising for the search for potential targetable alterations for treatments with new available drugs.

In vitro study of the UV-filter homosalate effects on rat and human thyroid cells.

Homosalate is a UV-B filter, commonly used in sunscreens and personal-care products. Homosalate was shown to exert estrogenic and anti-androgenic effects in animal models, while few data are available on the effects of Homosalate on thyroid cells. The aim of this study was to evaluate if Homosalate exposure could exert adverse effect on thyroid cells in vitro. FRTL-5 and NHT were treated with increasing concentration of Homosalate for 24-48-72 h. Cell viability was assessed by WST-1. Cell proliferation was evaluated by cristal violet. Micronucleus staining was performed to assess genotoxicity. mRNA levels of thyroid-related genes (TSHR, TPO, TG, NIS, and PAX8) were evaluated by RT-PCR. Changes in ROS production by FRTL-5 and NHT were assessed with H2DCFDA. Homosalate significantly reduced cell viability after 72 h in FRTL-5 starting from the concentration 250 µM, while in NHT, Homosalate exposure significantly reduced cell viability after 48 and 72 h only at highest concentration (2000 µM). Cell proliferation was not modified by Homosalate at any concentration and time-point. Homosalate significantly up-regulated mRNA expression levels of TPO and Tg genes in FRTL-5, while a significant increase only in Tg mRNA expression was observed in NHT. No changes in ROS production was found in both cell types. The present study suggest that the effects of Homosalate exposure may differ according to the type of cell tested. The in vitro exposure of thyroid cells to Homosalate produces: i) cytotoxicity at high concentrations or after long time of incubation, ii) genotoxicity only in rat thyroid cells at the highest concentration, iii) upregulation of Tg mRNA in both thyroid cell types and of TPO mRNA in rat thyroid cells, iv) no changes in cell proliferation or oxidative stress. Further studies on the effects of Homosalate on thyroid cells should be encouraged.

Fecal calprotectin measurement as a biomarker of severe disease phenotype in celiac disease and non-celiac enteropathies.

BACKGROUND: Fecal calprotectin (FC) is a non-invasive biomarker of gut inflammation, but its role in celiac disease (CD) and non-celiac enteropathies (NCEs) is undefined. AIMS: To retrospectively evaluate FC in patients with CD and NCEs as a tool for assessing disease activity and predicting long-term outcomes. METHODS: Patients with uncomplicated and complicated CD, and NCEs with data on FC, evaluated at our center between June-2008 and December-2023, were enrolled. The relationship between elevated FC (>50 mg/kg) and disease activity was statistically analysed and Cox regression adjusted for age and sex was used to compare development of complications and mortality in patients with elevated and normal FC. RESULTS: 177 patients (109F, mean age at diagnosis 39±20 years, 132 CD, 17 complicated CD, 28 NCEs) were enrolled. 55 patients had elevated FC, which was associated with lack of clinical and histological response to therapy (both p < 0.001). During a median follow-up of 103 months (IQR 54-176), 22 patients developed complications (15.4 %) and 21 died (11.9 %). Elevated FC was significantly more common in complicated CD (70.6 %) and NCEs (67.9 %) than in uncomplicated CD (18.2 %), p < 0.001. Elevated FC was independently predictive of developing complications (HR 4.8,95 %CI 1.4-17.7, p = 0.01) and mortality (HR 4.8,95 %CI 1.6-14.3, p < 0.01). CONCLUSION: FC is a promising non-invasive biomarker for assessing disease severity and long-term outcomes in CD and NCEs.

Flow cytometry for the assessment and monitoring of aberrant intraepithelial lymphocytes in non-responsive celiac disease and non-celiac enteropathies.

BACKGROUND: Few data are available on flow cytometry (FC) for monitoring intraepithelial lymphocytes (IELs) in refractory celiac disease (RCD), non-responsive celiac disease (NRCD), and non-celiac enteropathies (NCEs). AIMS: 1) To investigate the significance of monitoring IELs immunophenotype with FC in patients with NRCD, RCD and NCEs; 2) to evaluate FC concordance with immunohistochemistry (IHC) and γ-TCR clonality analysis. METHODS: Patients investigated between January-2012 and February-2023 were divided into two groups: 1)confirmed RCD or NRCD being investigated for persistent symptoms and suspected complications of celiac disease (CD); 2)NCEs lacking clinical/histological response. Clinical/molecular features and outcomes were retrospectively collected and analysed according to presence/absence of aberrant IELs on FC (cut-off≥20 % CD103+sCD3-CD8-iCD3+ IELs). RESULTS: 52 patients (18 RCD,21 NRCD,13 NCEs; 38F, 55±13 years; median follow-up 30 months, IQR 2-58) underwent 100 FC IELs determinations. 22/52 had ≥2 FC determinations and IEL phenotype remained unchanged over time in all them (κ=1.00). Aberrant IEL phenotype in CD was associated with increased mortality (HR 4.2, 95 % CI 1.5-11.9, p < 0.01). No patients with NCEs had an aberrant IEL phenotype at FC, although 3/13 developed lymphoma and 4/13 died. Concordance of FC was fair with both IHC (κ=0.40) and γ-TCR clonality analysis (κ=0.22). CONCLUSION: FC is accurate for assessing and monitoring IEL phenotype and providing important prognostic information in celiac patients. Further study is needed on its role in NCEs.

Mismatch repair deficiency as prognostic factor for stage III small bowel adenocarcinoma: A multicentric international study.

BACKGROUND: Small bowel adenocarcinoma (SBA) is a rare cancer with an aggressive behavior. No study has specifically addressed the putative prognostic role of mismatch repair status in stage III SBAs. AIMS: We aimed to investigate whether mismatch repair deficiency is associated with cancer-specific survival in a Western cohort of patients with stage III SBAs. METHODS: In this retrospective multicentric international cohort study, we enrolled 70 patients who underwent surgically resection for stage III SBAs and we analyzed the frequency of mismatch repair deficiency, tested by immunohistochemistry for mismatch repair proteins and by polymerase chain reaction for microsatellite instability, and its association with cancer-specific survival and other clinic-pathologic factors. RESULTS: We found sixteen (23%) patients with mismatch repair deficient adenocarcinoma, without discordance between immunohistochemical and polymerase chain reaction for microsatellite instability analyses. Mismatch repair deficiency proved to be associated with a better outcome both at univariable analysis (hazard ratio: 0.28, 95% confidence interval: 0.08-0.91, p: 0.035) and in bivariable models adjusted for patient age or gender, tumor site, pT4 stage, tumor budding, and perineural invasion. CONCLUSION: This study highlights the importance of testing mismatch repair status to improve prognostic stratification in stage III SBAs.

Case Report: Two Is Not (Always) Better Than One: Pyloric Gland Adenoma of the Gastric Cardia and Concurrent Neuroendocrine Cell Dysplasia Arising From Autoimmune Gastritis.

Autoimmune gastritis is a chronic immune-mediated disorder characterized by varied clinical manifestations and that should be endoscopically managed over time, as the gastric atrophy contributes to microenvironmental alterations of the stomach milieu, and an increased cancer risk has been linked to this condition. Here, we report the unusual case of a woman who developed a cardiac high-grade pyloric adenoma in a context of previously undiagnosed autoimmune gastritis with synchronous neuroendocrine cell hyperplastic and dysplastic lesions.