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. Patients with a different inflammatory pattern were more likely to have restarted ICI therapy before their follow-up biopsy (64%) compared to those without a change in inflammatory pattern (11%; P < 0.01). The majority of these patients had changed ICI drug types (86%). Additionally, many cases changed to an inflammatory bowel disease (IBD)-like pattern (36%), raising a question of de novo IBD. However, all of our patients with an IBD-like pattern experienced sustained resolution of symptoms without steroids or other immunosuppressive medications following discontinuation of ICI therapy, consistent with a diagnosis of ICI toxicity. Our findings suggest that follow-up biopsies in patients with ICI colitis may show a different histology and that this does not necessarily warrant a change in the histologic diagnosis to another disease.

High risk features in colorectal adenomatous polyps: A multi-institutional study

High risk features in colorectal adenomatous polyps include size >1 cm and advanced histology: high-grade dysplasia and villous architecture. We investigated whether the diagnostic rates of advanced histology in colorectal adenomatous polyps were similar among institutions across the United States, and if not, could differences be explained by patient age, polyp size, and/or CRC rate. Nine academic institutions contributed data from three pathologists who had signed out at least 100 colorectal adenomatous polyps each from 2018 to 2019 taken from patients undergoing screening colonoscopy. For each case, we recorded patient age and sex, polyp size and location, concurrent CRC, and presence or absence of HGD and villous features. A total of 2700 polyps from 1886 patients (mean age: 61 years) were collected. One hundred twenty-four (5 %) of the 2700 polyps had advanced histology, including 35 (1 %) with HGD and 101 (4 %) with villous features. The diagnostic rate of advanced histology varied by institution from 1.7 % to 9.3 % (median: 4.3 %, standard deviation [SD]: 2.5 %). The rate of HGD ranged from 0 % to 3.3 % (median: 1 %, SD: 1.2 %), while the rate of villous architecture varied from 1 % to 8 % (median: 3.7 %, SD: 2.5 %). In a multivariate analysis, the factor most strongly associated with advanced histology was polyp size >1 cm with an odds ratio (OR) of 31.82 (95 % confidence interval [CI]: 20.52-50.25, p < 0.05). Inter-institutional differences in the rate of polyps >1 cm likely explain some of the diagnostic variance, but pathologic subjectivity may be another contributing factor.

Esophageal squamous cell carcinoma with pagetoid spread: a clinicopathologic study

Pagetoid spread in esophageal squamous epithelium associated with underlying esophageal adenocarcinoma (EAC) has been well studied. Case reports describing pagetoid spread of esophageal squamous cell carcinomas (ESCC) also exist in the literature. The latter, however, has not been systematically studied. In this study, we report seven cases of pagetoid spread associated with ESCC. The clinical, morphologic, and immunophenotypic profiles of pagetoid spread in the context of ESCC and EAC are compared. Cases of pagetoid spread of ESCC were identified through computerized search of pathology archives at five institutions. Additional cases were identified through manual review of surgical resection cases of treatment naive ESCC in Mass General Brigham (MGB) pathology archive. Clinical history was collected via chart review. Immunohistochemistry for CK7, CK20, CDX2, p53, p63, and p40 was performed on selected cases. A computerized search of pathology archives of five institutions revealed only two cases. A manual review of 76 resected untreated ESCC revealed five additional cases with unequivocal pagetoid spread of ESCC, indicating the condition was not uncommon but rarely reported. Patient age ranged from 54 to 78 years (median, 65). There were six women and one man. One case had in situ disease, five had pT1 (1 pT1a and 4 pT1b), and one had pT3 disease. One of the patients with pT1 tumor had a positive lymph node, while the remaining six patients were all N0. Four tumors were in the proximal to mid esophagus, and three in the distal esophagus. Patient survival ranged from 25 months to more than 288 months. The pagetoid tumor cells demonstrated enlarged, hyperchromatic nuclei with variable amounts of eosinophilic cytoplasm. The cytoplasm was often condensed to the perinuclear area, creating peripheral clearing. By immunohistochemistry, the pagetoid cells were positive for p40 (6/6) and p63 (7/7) and negative for CDX2 (7/7). The tumor cells showed mutant-type staining for p53 in five of seven cases. One of the patients had pagetoid tumor cells at the resection margin and subsequently had recurrent disease 2 years later. All other patients had negative resection margins and did not have local recurrence. Four cases of pagetoid spread in the context of EAC were used as a comparison group. Previously published studies were also analyzed. These tumors were all located in the distal esophagus or gastroesophageal junction. All cases were associated with underlying invasive EAC. Pagetoid spread associated with EAC often had cytoplasmic vacuoles or mucin. They were more frequently positive for CK7 than pagetoid ESCC (p = 0.01). Both ESCC and EAC may give rise to pagetoid spread of tumor cells within surface squamous epithelium. Pagetoid spread from ESCC and EAC have overlapping morphologic features. P40 and p63 immunostains can facilitate the distinction between ESCC and EAC. P53 immunostain can aid in confirmation of malignancy. Understanding their overlapping pathologic features will help pathologists avoid pitfalls and diagnose these lesions correctly on biopsy specimens.

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.

RESULTS

1069 liver lesions were debulked from 53 patients using a combination of parenchymal-sparing resections (PSR) and ultrasound-guided microwave ablations (MWA). Post-operative transaminitis and thrombocytopenia were common, and severity correlated with increasing number of lesions. Laboratory markers for synthetic liver function did not differ according to the number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3 or 4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to progression was 10.9 months.

CONCLUSIONS

PSR with MWA for large numbers of NETLM is safe and effective for symptom control and does not affect synthetic liver function.

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. The patients were found to harbor pathogenic variants in telomeropathic genes (POT1 and DCLRE1B). Clonality testing for one of the patients showed evidence of evolving clonality of TCR-gene rearrangement. Both patients showed significantly decreased numbers of stem/progenitor cells by immunohistochemistry, which appears to be responsible for the development of mucosal atrophy. No such cases of unusual chronic atrophic gastritis in the setting of telomeropathy have been previously reported. The loss of stem/progenitor cells suggests that stem/progenitor cell exhaustion in the setting of telomere dysfunction is the likely mechanism for development of this unusual chronic atrophic gastritis. The results underscore the need for close monitoring of these gastric lesions, with special regard to their neoplastic potential. This combined WES-driven approach has promise to identify the cause and mechanism of other uncharacterized gastrointestinal inflammatory disorders.

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. The Cancer Genome Atlas program sub-classified GC into molecular subtypes, providing a framework for treatment personalization using traditional chemotherapies or biologics. Here, we report a comprehensive study of GC vascular and immune tumor microenvironment (TME)-based on stage and molecular subtypes of the disease and their correlation with outcomes. Using tissues and blood circulating biomarkers and a molecular classification, we identified cancer cell and tumor archetypes, which show that the TME evolves with the disease stage and is a major determinant of prognosis. Moreover, our TME-based subtyping strategy allowed the identification of archetype-specific prognostic biomarkers such as CDH1-mutant GC and circulating IL-6 that provided information beyond and independent of TMN staging, MSI status, and consensus molecular subtyping. The results show that integrating molecular subtyping with TME-specific biomarkers could contribute to improved patient prognostication and may provide a basis for treatment stratification, including for contemporary anti-angiogenesis and immunotherapy approaches.

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. A recent emphasis on unifying themes has driven an increasingly standardized approach to NEN classification, as delineated in the World Health Organization's Classification of Tumours series. Here, we review recent developments in NEN classification, with a focus on NENs of the pancreas and lungs.

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.

RESULTS

Two hundred and six patients with UC were included; 13 patients (6%) had histologically confirmed CMV colitis. Eleven of 13 patients with CMV colitis (84%) and 3 of 193 (1.5%) patients without CMV colitis had a positive serum PCR test (p < 0.0001). ROC analysis showed that a CMV PCR level of 259 IU/mL had a sensitivity and specificity of 77% and 99%, respectively, for diagnosis of CMV colitis with an AUC of 0.9 (p < 0.0001). Serum CMV PCR level significantly correlated to the number of inclusion bodies on biopsy specimens with data available (n = 8) (r = 0.8, p = 0.02). CMV positivity did not predict the need for salvage therapy, admission or 1-year colectomy rates.

CONCLUSION

Serum CMV PCR has an excellent negative predictive value and demonstrates a strong correlation with CMV positivity on histology. This work supports a rationale for serum CMV PCR testing on admission to assess the risk of CMV colitis in patients with severe UC.

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. We aimed to validate an EUS-based risk classification system predicting risk for M1 disease.

Methods

We retrospectively identified all GC patients without positron emission tomography (PET)/computed tomography (CT) evidence of distant metastasis who underwent staging EUS followed by DSL between 2010 and 2020. T1-2, N0 disease was EUS "low-risk"; T3-4 and/or N+ disease was "high-risk".

Results

A total of 68 patients met inclusion criteria. DSL identified radiographically occult M1 disease in 17 patients (25%). Most patients had EUS T3 tumors (n = 59, 87%) and 48 (71%) patients were node-positive (N+). Five (7%) patients were classified EUS "low-risk" and 63 (93%) were classified "high-risk". Of 63 "high-risk" patients, 17 (27%) had M1 disease. The ability of "low-risk" EUS to predict M0 disease at laparoscopy was 100% and DSL would have been avoided in five patients (7%). This stratification algorithm showed a sensitivity of 100% (95% confidence interval (CI): 80.5-100%) and a specificity of 9.8% (95% CI: 3.3-21.4%).

Conclusions

Use of an EUS-based risk classification system in GC patients without imaging evidence of metastasis helps identify a subset of patients at low-risk for laparoscopic M1 disease who may avoid DSL and proceed directly to neoadjuvant chemotherapy or resection with curative intent. Larger, prospective studies are needed to validate these findings.

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. Haematoxylin and eosin (H&E) slides from gastric biopsies were reviewed. Fifteen patients (14 female, one male) were identified. The most common presenting symptoms were diarrhoea (10) and weight loss (six). Gastric biopsies commonly showed a full-thickness active chronic gastritis with surface epithelial injury involving the antrum and body. Glandular atrophy, intra-epithelial lymphocytosis and/or subepithelial collagen thickening were also present in some cases. Duodenal involvement, including villous atrophy, intra-epithelial lymphocytosis and/or collagenous sprue, was identified in 11 of 13 cases with concurrent duodenal biopsies. Following drug cessation, symptomatic improvement occurred in all 11 cases for which follow-up data were available. Histological resolution occurred in five of eight cases with follow-up gastric biopsies, with improvement seen in the remaining three biopsies.

CONCLUSION

ARB-induced gastritis typically presents as active chronic gastritis, frequently with associated surface epithelial injury. Glandular atrophy, intra-epithelial lymphocytosis and/or subepithelial collagen thickening may also be present. These gastric changes can be seen without associated duodenal injury in rare cases, and they should alert the pathologist to the possibility of ARB-induced injury. Drug cessation results in marked symptomatic and histological improvement.

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. However, pathologists face challenges in reproducibly measuring DOI.

OBJECTIVE.—

To determine how often DOI measurements could impact treatment and to evaluate reproducibility in measuring submucosal DOI in EMR specimens.

DESIGN.—

Consecutive adenocarcinoma EMR cases were identified, including cases of "low histologic risk" submucosal cancer, as follows: those with negative deep margins, no high-grade histology (G3), and no lymphovascular invasion. Submucosal DOI was measured by 7 pathologists according to guidelines.

RESULTS.—

Of 213 cancer EMR cases, 46 were submucosa invasive and 6 cases were low histologic risk submucosal cancers for which measurement could impact decision-making. Of these low histologic risk cases, 3 were categorized as superficial, indicating that measurement would be a clinically actionable decision point in only 1.4% of adenocarcinoma EMRs. Interobserver agreement for in-depth categorization between 7 pathologists was moderate (κ = 0.42), and the range of measurements spanned the 500-μm relevant threshold in 40 of 55 measured samples (72.7%).

CONCLUSIONS.—

While therapeutic decisions would rarely have depended on DOI measurements alone in our cohort, interobserver variability raises concerns about their use as a sole factor on which to offer patients conservative therapy. Responsibly reporting and clinically using submucosal DOI measurements will require practical experience troubleshooting common histologic artifacts, as well as multidisciplinary awareness of the impact of variable specimen-handling practices.

Outcomes in high-grade neuroendocrine carcinomas (HG-NEC) of the gastrointestinal (GI) tract with modern therapies

e15609

Background: HG-NEC of the GI tract are rare and aggressive neoplasms with poor prognosis. Approximately 37.5% of extra-pulmonary NEC are of the GI origin and are most commonly located in esophagus, stomach, pancreas and colon (1,2). Median survival of 7.5 months, with range of 5.7 months to 25.1 months has been reported (2). However, data regarding response to immunotherapy, as well as response to molecularly directed therapies are sparse. In this study, we conducted a retrospective review of GI tract HG-NEC with objective to assess role of modern diagnostics and therapies in clinical outcomes. Methods: We identified 14 patients with GI tract HG-NEC who received care at University of Chicago Medical Center (UCMC). Electronic medical records were reviewed for disease stage, treatments and clinical course. We reviewed available next generation sequencing (NGS) and circulating tumor DNA (ct-DNA) test results. In this cohort, UCMC’s NGS panel: Oncoplus was available and Guardant 360 results were reviewed for liquid biopsy. Results: In our initial review, site of origin included right side of colon (46%), left sided colon (46%), and anus/anorectal (15%). Median overall survival (mOS) ranged from 1.3 months to 81.3 months, and notably the median response to chemo-immunotherapy (IO) was 7.9 months (table 1). Notably one patient received maintenance therapy with immunotherapy alone with progression of disease (POD) in 3 weeks. Six patients had NGS results of which three (50%) had therapeutic targetable alterations (Table). Two patients had liquid biopsy done, of which one had targetable alterations and the other had no tumor related alterations detected. Of the two patients with targetable lesions, one patient has received targeted therapy with POD in 1.2 months and median OS 8.8 months; the other is in the process of initiating targeted therapy. Conclusions: To our knowledge, this is the first report to show a response to combination chemo-immunotherapy and targeted therapies in HG-NEC of GI tract. We are collaborating with other institutions to collate outcomes to similar therapy approaches in this patient cohort. With our study, we hope to inform future therapies and innovation in this important disease.

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. As such, the cohort stratified into 3 different clinically relevant chromosomal subgroups: an indolent subgroup characterized by loss of chromosome 11 in relative isolation, an aggressive subgroup characterized by losses of chromosomes 1, 2, 3, 6, 10, 11, 16, and 22 and with no loss of chromosomes 4, 5, 7, 12, 14, 17, 19, and 20, and finally a heterogeneous third group with a subset of cases that behave even more aggressively than the aforementioned.

Loss of MEN1 function impairs DNA repair capability of pancreatic neuroendocrine tumors

Somatic MEN1 mutations occur in up to 50% of pancreatic neuroendocrine tumors (PanNETs). Clinical studies have shown that radiation therapy (IR) is effective in a subset of PanNETs, but it remains unclear why some patients respond better to IR than others. Herein, we study whether MEN1 loss of function increases radiosensitivity of PanNETs and determine its effect on DNA double-strand break (DSB) repair. After creating a MEN1 knockout PanNET cell line, we confirmed reduced DSB repair capacity in MEN1-deficient cells and linked these findings to a defect in homologous recombination, as well as reduced BRCA2 expression levels. Consistent with this model, we found that MEN1 mutant cells displayed increased sensitivity to the highly trapping poly (ADP-ribose) polymerase (PARP) 1 inhibitor talazoparib in vitro. Our results suggest that combining IR with PARP inhibition may be beneficial in patients with PanNETs and MEN1 loss of function.

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. To determine intratumor heterogeneity of 5-hmC expression, 26 additional synchronous metastatic deposits of PanNETs from 8 patients were evaluated for 5-hmC expression. 5-hmC level showed significant association with the presence of distant metastases (P=0.02), female sex (P=0.04), and Ki-67 proliferation index (P=0.002). A multivariate model created using the stepwise logistic regression analysis showed the presence of nodal metastases (odds ratio=6.15), lymphovascular invasion (odds ratio=4.07) and lack of 5-hmC expression (odds ratio=5.34) were predictive of the risk of distant metastasis in PanNETs with a c-statistic of 0.845. Epigenetic intratumoral heterogeneity of 5-hmC expression was seen in 37.5% cases (3/8). Our work provides evidence that epigenetic regulators are involved in the pathobiology of PanNETs and immunohistochemical analysis of 5-hmC may be able to refine prognostic evaluation of these tumors.

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.

RESULTS

The cohort included 62 [64%] men and 35 [36%] women with a mean age of 49 years [range: 20-78]. The majority of affected patients had longstanding IBD [mean duration: 18 years]. Nineteen [20%] patients had a concurrent history of primary sclerosing cholangitis. As a group, non-conventional dysplasia was predominantly found in patients with ulcerative colitis [UC] [n = 68; 70%] and occurred in the left colon [n = 80; 63%]; however, hypermucinous dysplasia [57%] was the least frequently associated with UC compared with goblet cell-deficient [74%] and crypt cell [89%] dysplasias [p = 0.016]. Fifty [52%] patients had a history of conventional dysplasia, detected in the same colonic segment as non-conventional dysplasia at a rate of 33%. Goblet cell-deficient dysplasia [74%] was more frequently associated with conventional dysplasia than hypermucinous [43%] and crypt cell [48%] dysplasias [p = 0.044]. While hypermucinous dysplasia often had a polypoid appearance [58%], crypt cell [96%] and goblet cell-deficient [65%] dysplasias were more likely to present as flat/invisible lesions [p < 0.001]. Most lesions were low-grade [87%] at diagnosis, but goblet cell-deficient dysplasia [31%] more often showed high-grade dysplasia [HGD] compared with hypermucinous [15%] and crypt cell [0%] dysplasias [p = 0.003]. Hypermucinous dysplasia usually demonstrated a tubulovillous/villous architecture [76%], whereas goblet cell-deficient dysplasia was predominantly tubular [92%]. A flat architecture was exclusively associated with crypt cell dysplasia [100%] [p < 0.001]. Immunohistochemical stain results for p53 were available for 33 lesions; 14 [42%] showed strong [3+] and patchy [10-50%] to diffuse [>50%] nuclear overexpression or null staining pattern, including four [33%] of 12 hypermucinous, two [29%] of seven goblet cell-deficient and eight [57%] of 14 crypt cell dysplastic lesions [p = 0.726]. Follow-up biopsies or resections were available for 92 low-grade lesions from 71 patients; 55 [60%] lesions, including 19 [49%] of 39 hypermucinous, 10 [59%] of 17 goblet cell-deficient and 26 [72%] of 36 crypt cell dysplastic lesions [p = 0.116], were associated with subsequent detection of HGD [n = 34; 37%] or adenocarcinoma [n = 21; 23%] at the site of previous biopsy or in the same colonic segment within a mean follow-up time of 12 months [range: <1-73].

CONCLUSIONS

Hypermucinous, goblet cell-deficient and crypt cell dysplasias have distinct clinicopathological features but appear to have a similar high risk of association with advanced neoplasia [HGD or adenocarcinoma]. More than half of the lesions [66%] presented as flat/invisible dysplasia, suggesting that IBD patients may benefit from random biopsy sampling in addition to targeted biopsies. Although not uncommonly associated with conventional dysplasia, non-conventional dysplasia may be the only dysplastic subtype identified in IBD patients. Therefore, it is important to recognize these non-conventional subtypes and recommend complete removal and/or careful examination and follow-up.

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. We hypothesize that a new drug delivery system comprising chondroitin sulfate (CS) hydrogels loaded with sunitinib (SUN) suppresses tumor growth in PanNET cells.

METHODS

Injectable hydrogels composed of CS modified with methacrylate groups (MA) were fabricated and loaded with SUN. Loading target was either 200 µg (SUN200-G) or 500 µg (SUN500-G) as well as sham hydrogel with no drug loading (SUN0-G). SUN release from hydrogels was monitored in vitro over time and cytotoxicity induced by the released SUN was evaluated using QGP-1 and BON1 PanNET cell lines. QGP-1 xenografts were developed in 35 mice and directly injected with 25 µL of either SUN200-G, SUN500-G, SUN0-G, 100 µL of Sunitinib Malate (SUN-inj), or given 40 mg/kg/day oral sunitinib (SUN-oral).

RESULTS

SUN-loaded CSMA hydrogel retained complete in vitro cytotoxicity toward the QGP-1 PanNET and BON-1 PanNET cell lines for 21 days. Mouse xenograft models with QGP-1 PanNETs showed a significant delay in tumor growth in the SUN200/500-G, SUN-inj and SUN-oral groups compared with SUN0-G (p = 0.0014). SUN500-G hydrogels induced significantly more tumor necrosis than SUN0-G (p = 0.04). There was no difference in tumor growth delay between SUN200/500G, SUN-inj, and SUN-oral.

CONCLUSIONS

This study demonstrates that CSMA hydrogels loaded with SUN suppress PanNETs growth. This drug delivery could approach represents a novel way to treat PanNETs and other neoplasms via intratumoral injection.

Objective Visual Analog Scale for Biopsy Diagnosis of Helicobacter pylori Infection in Clinical Practice

Historic and current pathology society guidelines recommend using visual gestalt to identify substantial inflammatory cell infiltrate in Helicobacter pylori gastritis, but these scales were subjectively designed. This study aims to objectively investigate the density of inflammation that justifies additional workup for H. pylori infection. We retrospectively identified 2 patient cohorts who had undergone endoscopy with gastric biopsies; 1 with H. pylori infection (n=66), confirmed with a positive stool antigen test and/or Campylobacter-like organism test, and 1 without infection (n=81). Antral and body biopsies were selected from each case, if available, and stained with MUM-1 to highlight mucosal plasma cells. Digital analysis was performed to calculate the number of plasma cells/mm2, termed the "inflammatory score" (IS). Patients with H. pylori infection had an average of 1289 plasma cells/mm2 in the antrum and 835 plasma cells/mm2 in the body, compared with 346 plasma cells/mm2 in the antrum and 178 plasma cells/mm2 in the body in patients without infection. IS cut-off values for a positive infection were 714 plasma cells/mm2 in the antrum and 316 plasma cells/mm2 in the body, with high sensitivities and specificities in both the antrum (92%, 92%) and body (85%, 84%), respectively. A visual analog scale was created to provide a histologic correlate of the observed IS ranges and cut-offs. This practical and objective scale is associated with a high sensitivity and specificity for diagnosing H. pylori infection and justifies moving away from upfront universal H. pylori testing in routine clinical practice.

Histologic changes caused by injection of a novel submucosal lifting agent for endoscopic resection in GI lesions

BACKGROUND AND AIMS

ORISE Gel is a recently introduced, U.S. Food and Drug Administration-approved submucosal lifting agent used in endoscopic resection of GI lesions. Histologically evident gel deposits in resected specimens may pose a potential diagnostic pitfall. To aid in recognition of this procedure-related artifact, we report the largest histologic series of ORISE Gel in endoscopic and surgical resection specimens to date.

METHODS

Fifty-eight EMR/endoscopic submucosal dissection (ESD) specimens with ORISE Gel injection and 5 interval surgical resection specimens with previous ORISE Gel injection were included. Patient demographics and endoscopy reports were obtained. Histologic slides from all cases were reviewed. Histochemical stains were performed on select cases.

RESULTS

Fifty-one EMR and 7 ESD specimens were identified. In 51 of 58 (88%) endoscopic resection specimens, amorphous, pale blue-gray, finely granular material was evident in the submucosa, as well as focally within the mucosa in 4 cases. Most cases showed homogeneous near-complete filling of the submucosa with this material, whereas a few demonstrated areas of condensation and retraction. Mucicarmine and periodic acid-Schiff stains were negative for mucin. Interval surgical resection specimens revealed extensive deposition of dense, eosinophilic material with associated multinucleated giant cells in the submucosa in all cases, with transmural extension in 3 cases.

CONCLUSION

ORISE Gel injection during endoscopic resection of GI lesions results in deposition of amorphous, blue-gray material seen in histologic sections, whereas interval surgical resection specimens demonstrate dense, eosinophilic material with an associated giant cell reaction. Awareness of these artifacts will help avoid misinterpretation of their presence as pathologic findings.

Morphologic and molecular analysis of early-onset gastric cancer

BACKGROUND

Evidence suggests that early-onset gastric cancers are distinct from traditional gastric cancers; however, detailed genomic and morphologic characterization of these cancers has not been performed.

METHODS

Genomic analysis was performed for 81 patients with gastric cancer who were 50 years old or younger; pathology slides were available for 53 of these patients, and they were re-reviewed to perform a morphologic-molecular correlation analysis. The results were compared with corresponding cBioPortal data and The Cancer Genome Atlas (TCGA) analysis, which represent traditional gastric cancers. The TP53 molecular signature was established to determine the pattern of somatic mutational damage. Variants of potential germline origin were also identified from next-generation sequencing data.

RESULTS

A higher rate of CDH1 mutations (22.2% of early-onset gastric cancers vs 11.4% of traditional gastric cancers; P = .0042) but a similar rate of TP53 mutations (63% of early-onset gastric cancers vs 56.6% of traditional gastric cancers; P = .2674) were seen in early-onset cancers in comparison with traditional gastric cancers. The diffuse/mixed types correlated with the TCGA genomically stable type, and the remaining Lauren types correlated with the TCGA chromosomal instability type. Diffuse and indeterminate histologic types (overall survival, 26.25 months for the intestinal type, 20.5 months for the mixed type, 12.62 months for the diffuse type, and 9 months for the indeterminate type; P = .027) and the presence of a CDH1 gene mutation (overall survival, 9 months for mutant CDH1 and 22 months for wild-type CDH1; P = .013) significantly correlated with worse survival. The TP53 gene frequently showed transition mutations (65.5%) involving the CpG sites (49%). Variants of potential germline origin were seen in high-penetrance genes (CDH1 and APC) and moderate-penetrance genes (ATM, NBN, and MUTYH) in 9.9% of cancers.

CONCLUSIONS

Early-onset gastric cancer has distinct genomic alterations, such as CDH1 mutations, but shares with traditional gastric cancers a high frequency of TP53 mutations and the TP53 mutagenic signature. Diffuse and indeterminate histologic types and the presence of a CDH1 mutation are associated with worse overall survival. Endogenous factors leading to cytosine deamination and potential germline alterations in moderate-penetrance cancer susceptibility genes may be implicated in the pathogenesis of these cancers.

Personalized Antibodies for Gastroesophageal Adenocarcinoma (PANGEA): A Phase II Study Evaluating an Individualized Treatment Strategy for Metastatic Disease

The one-year and median overall survival (mOS) rates of advanced gastroesophageal adenocarcinomas (GEA) are ∼50% and <12 months, respectively. Baseline spatial and temporal molecular heterogeneity of targetable alterations may be a cause of failure of targeted/immunooncologic therapies. This heterogeneity, coupled with infrequent incidence of some biomarkers, has resulted in stalled therapeutic progress. We hypothesized that a personalized treatment strategy, applied at first diagnosis then serially over up to three treatment lines using monoclonal antibodies combined with optimally sequenced chemotherapy, could contend with these hurdles. This was tested using a novel clinical expansion-platform type II design with a survival primary endpoint. Of 68 patients by intention-to-treat, the one-year survival rate was 66% and mOS was 15.7 months, meeting the primary efficacy endpoint (one-sided P = 0.0024). First-line response rate (74%), disease control rate (99%), and median progression-free survival (8.2 months) were superior to historical controls. The PANGEA strategy led to improved outcomes warranting a larger randomized study. SIGNIFICANCE: This study highlights excellent outcomes achieved by individually optimizing chemotherapy, biomarker profiling, and matching of targeted therapies at baseline and over time for GEA. Testing a predefined treatment strategy resulted in improved outcomes versus historical controls. Therapeutic resistance observed in correlative analyses suggests that dual targeted inhibition may be beneficial.This article is highlighted in the In This Issue feature, p. 211.

Personalized antibodies for gastroesophageal adenocarcinoma (PANGEA): Secondary and final primary efficacy analyses

4561

Background: Targeted therapies (tx) have had limited benefit in advanced (aGEA) due to baseline spatial (primary vs metastatic tumor PT/MT) & temporal molecular heterogeneity (BMH/TMH). We previously reported PANGEA methods & results: 35% BMH rate & 10 OS results achieving 1yr OS of 66% & mOS of 16.4 months (m) using the personalized tx strategy (Catenacci et al. GI ASCO 2020 Abstr356). Here we will report the TMH rates at progressive disease points (PD1 & PD2), ORR/PFS/DCR in each of 3 tx lines, time to strategy failure (TTF), & updated OS/safety. Methods: PANGEA enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) tx lines (L). Baseline tissue biomarker profiling (BP) was mandated on PT/MT & PD1/PD2, & ctDNA analysis throughout. After initiating 1L cx & upon learning MT BP results, antibody (AN) was added by a predefined prioritized tx algorithm incorporating tissue & blood BP (Table). At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per tx algorithm. The same was done at PD2. The 10 endpoint was 1yr OS; enrolling 68 pts provided 80% power to detect a 63% 1yr OS compared to historical 50% 1yr OS (HR 0.67), using a 1-sided test (0.10 alpha). Results: 80 pts were enrolled, & 68 tx’d per protocol. At data cut-off 2/1/20, 15 pts were still on trial with only 2 of these pts on tx <12m (8 pts in 1L, 5 in 2L, 2 in 3L). All 68 pts had at least 1 dose of 1L tx, 87% 2L tx, & 36% 3L tx. AN assigned by the tx algorithm at 1L, OS, TTF, & ORR1/PFS1/DCR1 of 1L tx are shown in Table; 2L & 3L ORR/DCR outcomes will be shown. The 3yr & 4yr OS rates were 12% & 8%. TMH leading to molecular subgroup change by tx algorithm was 51% after 1L & 36% after 2L; details & results by subgroup will be provided. Any grade >3 non-heme tox thru all 3 tx lines was seen in 25% of pts. Conclusions: PANGEA showed superior 10 & 20 endpoint efficacy, even when excluding HER2- pts, compared to historical outcomes. Clinical trial information: NCT02213289 . [Table: see text]

Morphologic and molecular analysis of early-onset gastroesophageal adenocarcinomas

4547

Background: The incidence of early-onset gastroesophageal adenocarcinomas (EO-GEA) is increasing, and these tumors now constitute > 30% of all gastroesophageal cancers. Besides hereditary gastric cancer syndromes, which form ~3% of EO-GEA, the morphologic and molecular spectrum of these tumors is not well-studied. Methods: Next-generation sequencing (NGS) data obtained from routine clinical care from patients with EO-GEA, defined as age ≤50 years, from 3 tertiary care centers was evaluated and compared with tumor profiles of 2,081 patients with GEA from cBioPortal for Cancer Genomics. Available histologic slides were reviewed, and the tumors were classified into Lauren and WHO subtypes. Tumor-detected pathogenic variants of potential germline origin were identified from the NGS data. Results: The study cohort was formed by 79 patients with gastroesophageal (42%) and gastric (58%) adenocarcinoma. The most commonly mutated genes included TP53 (28.5%), CDH1 (10%), ARID1A (5%), KRAS (3.9%) and PIK3CA (3.9%). EO-GEA were less likely to harbor TP53 (28.5% vs. 57.5%, p 0.003) and ARID1A (5% vs. 20.6%, p 0.002) mutations when compared with cBioPortal data. Based on the Lauren scheme, the tumors were classified into intestinal (40%), diffuse (24%), mixed (12%), and indeterminate (15%) subtypes. Driver mutations in CDH1, TP53, FBXW7, BAP1 genes were seen in diffuse/mixed subtype, and TP53, ARID1A, KRAS, PIK3CA, APC, ATM, NBN, MUTYH genes in intestinal subtype. The indeterminate subtype showed TP53 mutations and additional alterations, including SMARCB1/ SMARCA4 loss leading to rhabdoid/undifferentiated morphology. ERBB2 amplification was more likely to be present in intestinal and indeterminate subtypes (p = 0.003). CD274 amplification/PD-L1 expression was more likely to be present in indeterminate subtype (p < 0.0001). Potential germline variants included mutations in gastric cancer susceptibility genes such as CDH1 (2.5%) and APC (1%), and other cancer susceptibility genes such as ATM (4%), NBN (1%), MUTYH (1%) and POLD1 (1%). Conclusions: The molecular profile of EO-GEA is distinct from traditional gastric cancers. Histologic subtypes of EO-GEA correlate with distinct genomic alterations. Our findings also support multigene germline panel testing in parallel for patients with EO-GEA.

Evaluation of the Association of Perioperative UGT1A1 Genotype-Dosed gFOLFIRINOX With Margin-Negative Resection Rates and Pathologic Response Grades Among Patients With Locally Advanced Gastroesophageal Adenocarcinoma: A Phase 2 Clinical Trial

IMPORTANCE

Patients with locally advanced gastroesophageal adenocarcinoma (ie, stage ≥T3 and/or node positive) have high rates of recurrence despite surgery and adjunctive perioperative therapies, which also have high toxicity profiles. Evaluation of pharmacogenomically dosed perioperative gFOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and UGT1A1 genotype-directed irinotecan) to optimize efficacy while limiting toxic effects may have value.

OBJECTIVE

To evaluate the coprimary end points of margin-negative (R0) resection rates and pathologic response grades (PRGs) of gFOLFIRINOX therapy among patients with locally advanced gastroesophageal adenocarcinoma.

DESIGN, SETTING, AND PARTICIPANTS

This single-group phase 2 trial, conducted at 2 academic medical centers from February 2014 to March 2019, enrolled 36 evaluable patients with locally advanced adenocarcinoma of the esophagus, gastroesophageal junction, and gastric body. Data analysis was conducted in May 2019.

INTERVENTIONS

Patients received biweekly gFOLFIRINOX (fluorouracil, 2400 mg/m2 over 46 hours; oxaliplatin, 85 mg/m2; irinotecan, 180 mg/m2 for UGT1A1 genotype 6/6, 135 mg/m2 for UGT1A1 genotype 6/7, or 90 mg/m2 for UGT1A1 genotype 7/7; and prophylactic peg-filgastrim, 6 mg) for 4 cycles before and after surgery. Patients with tumors positive for ERBB2 also received trastuzumab (6-mg/kg loading dose, then 4 mg/kg).

MAIN OUTCOMES AND MEASURES

Margin-negative resection rate and PRG.

RESULTS

A total of 36 evaluable patients (27 [78%] men; median [range] age, 66 [27-85] years; 10 [28%] with gastric body cancer; 24 [67%] with intestinal-type tumors; 6 [17%] with ERBB2-positive tumors; 19 [53%] with UGT1A1 genotype 6/6; 16 [44%] with genotype 6/7; and 1 [3%] with genotype 7/7) were enrolled. Of these, 35 (97%) underwent surgery; 1 patient (3%) died after completing neoadjuvant chemotherapy while awaiting surgery. Overall, R0 resection was achieved in 33 of 36 patients (92%); 2 patients (6%) with linitis plastica achieved R1 resection. Pathologic response grades 1, 2, and 3 occurred in 13 patients (36%), 9 patients (25%), and 14 patients (39%), respectively, and PRG 1 was observed in 11 of 24 intestinal-type tumors (46%). Median disease-free survival was 30.1 months (95% CI, 15.0 months to not reached), and median overall survival was not reached (95% CI, 8.3 months to not reached). There were no differences in outcomes by UGT1A1 genotype group. A total of 38 patients, including 2 (5%) with antral tumors, were evaluable for toxic effects. Grade 3 or higher adverse events occurring in 5% or more of patients during the perioperative cycles included diarrhea (7 patients [18%]; 3 of 19 patients [16%] with genotype 6/6; 2 of 16 patients [13%] with genotype 6/7; 2 of 3 patients [67%] with genotype 7/7), anemia (2 patients [5%]), vomiting (2 patients [5%]), and nausea (2 patients [5%]).

CONCLUSIONS AND RELEVANCE

In this study, perioperative pharmacogenomically dosed gFOLFIRINOX was feasible, providing downstaging with PRG 1 in more than one-third of patients and an R0 resection rate in 92% of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02366819.

Personalized ANtibodies for GastroEsophageal Adenocarcinoma (PANGEA): Primary efficacy analysis of the phase II platform trial (NCT02213289)

356

Background: 1-yr OS is ~40% for HER2- & ~55% for HER2+ advanced (aGEA). Targeted therapies (tx) have had limited benefit due to molecular heterogeneity. Methods: This phase 2a study of a personalized tx strategy (PTS) enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) lines: first line (1L) 5FU + oxaliplatin, 2L 5FU + irinotecan & 3L 5FU + docetaxel. Baseline biomarker profiling (BP) was mandated on primary & metastatic tumors (PT/MT) & progressive disease points (PD1, PD2). Assigned antibody (AN) was added to cx by a predefined prioritized tx algorithm (PTA) (Table) based on the MT BP. At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per PTA. The same was done at PD2. If AN was unavailable (MET/FGFR2), these pts were tx’d with cx alone (not ITT). The 10 endpt was 1-yr OS of the PTS. Assuming historical 50% 1-yr OS for all aGEA pts, 68 pts tx’d per protocol PTS provided 80% power to detect an HR=0.67, corresponding to a 1-yr OS rate of 63% (under exponential survival), using a 1-sided test at the 0.10 alpha level. 20 endpts: safety, feasibility, PT/MT BP discordance at baseline & over tx line, & OS/PFS/ORR by tx line & BP group. Results: Between 6/2015-5/2019, 80 consecutive pts enrolled at 3 sites: ECOG PS 0-2 40/33/7; Male 80%; median age 60, range 28-81, peritoneal disease 36%. AN assigned by PTA at 1L & 1-yr OS are shown (Table). PT/MT discordance was 37%. Of 68 pts treated by PTS ITT, the 1-yr OS was 69.4% (p<0.001). The mOS was 16.4m [95%CI 13.8-20.8]. Any grade >3 tox thru all 3 tx lines was seen in 32% of pts. 20 analyses will be presented. Conclusions: PANGEA was feasible & met its 10 efficacy objective with observed 1-yr OS of 69.4%, meriting a randomized study. Clinical trial information: NCT02213289 . U.S. National Institutes of Health.[Table: see text]

Clinicopathological features of pyloric gland adenomas of the duodenum: a multicentre study of 57 cases

AIMS

To determine the clinicopathological features of pyloric gland adenomas (PGA) that arise in the duodenum.

METHODS AND RESULTS

Fifty-seven cases of duodenal PGA were identified and analysed from 56 patients. Clinicopathological and immunohistochemical analyses were performed. PGA tend to occur in older individuals (median age = 73.5), with a slight female predominance (25 males, 31 females). PGA arise more commonly in the proximal duodenum (68.75% in D1, 25% in D2 and 6.25% in D3) and usually present as mucosal nodules (98.2%) or plaques (1.8%), with a mean size of 14.8 mm. There is associated gastric heterotopia in 22.8% of cases. PGA showing features of high-grade dysplasia were significantly larger in size than PGA, showing only low-grade dysplasia (23.1 versus 8.7 mm; P = 0.0001) and more likely to show a tubulovillous rather than a pure tubular architecture (P = 0.025). In our series, 10 of 56 patients had intramucosal or invasive carcinoma associated with the duodenal PGA (17.9%). Three of these carcinomas showed lymph node metastasis. Following definitive treatment, local recurrence occurred in only three patients.

CONCLUSIONS

Duodenal PGA tend to occur in the proximal duodenum of older individuals. Larger size and tubulovillous architecture correlates with high-grade dysplasia and associated adenocarcinoma. The low recurrence rate of these lesions would suggest that endoscopic management is appropriate, provided that the lesion can be completely resected.

Next-generation sequencing identifies 2 genomically distinct groups among pyloric gland adenomas

The molecular alterations identified among pyloric gland adenomas (PGAs) in the published literature are based on polymerase chain reaction of targeted genes, and next-generation sequencing (NGS) has not been performed. In this study, we performed NGS and correlated the molecular alterations with the histologic grade of dysplasia and immunohistochemical findings in a cohort of PGAs. Successful DNA extraction and sequencing were performed in 15 pyloric gland adenomas/adenocarcinoma from 12 patients. Additionally, 4 specimens of autoimmune gastritis were selected to serve as the control group. Ten PGAs with low-grade dysplasia were seen to have mutations in the triad of APC, KRAS, and GNAS genes. Five PGAs with high-grade dysplasia/adenocarcinoma exhibited mutations in several genes including APC, CTNNB1, KRAS, GNAS, TP53, CDKN2A, PIK3CA, and EPHA5 genes but did not exhibit mutations in the triad of APC, KRAS, and GNAS genes. The median tumor mutational burden was higher in PGAs with high-grade dysplasia/adenocarcinoma when compared with PGAs with low-grade dysplasia (5.25 and 4.38, respectively). PGAs with high-grade dysplasia/adenocarcinoma had more chromosomal gains and losses than PGAs with low-grade dysplasia. The molecular findings suggest that there are 2 separate mutator pathways of dysplasia development in PGAs.

Predictive value of WHO classification for PD-L1 and Her2/Neu expression and distinct associations with protein expression based classification in gastric carcinoma

The Cancer Genome Atlas data on gastric carcinoma has identified four biologic pathways as potential drivers of gastric carcinogenesis and suggested targeted therapies based on the genomic alterations underscoring each subset. The correlation between morphology, biologic groups and their corresponding biomarkers has been eluded in several previous studies; however, a comprehensive analysis in consideration of the recent advancements has not been performed. In this study we explored the predictive value of morphology for biomarker expression and its association with protein expression based classification of gastric carcinoma. Four hundred eighty six gastric carcinomas which had been classified into protein expression-based groups formed the case cohort. Upon analysis, we found a low positive predictive value of an individual morphologic pattern for biomarker-expression, indicating that an individual morphologic pattern alone cannot predict PD-L1, Her2/neu expression and EBV- or MSI-gastric cancer. A combination approach targeting the test in certain WHO patterns can be employed for maximizing the positive predictive values. These include, PD-L1 testing in tubular, carcinoma with lymphoid stroma, undifferentiated and poorly cohesive patterns and Her2/neu testing in tubular, mixed, papillary, mucinous and solid patterns. The predictive values and morphologic associations presented here have the potential to select patients for personalized therapy.

Actinomyces in Crohn's-like appendicitis

AIMS

Appendicitis with a Crohn's-like histological appearance generally raises concern for Crohn's disease, Yersinia infection, and interval appendectomy. Actinomyces infection is a recognised cause of chronic appendicitis that can histologically mimic Crohn's disease.

METHODS AND RESULTS

We report on 20 cases of appendicitis with Crohn's-like histological features that were due to Actinomyces. Most patients presented with acute or chronic abdominal pain. Imaging studies suggested a mass in five cases. Two patients had interval appendectomy. Histological features showed Crohn's-like appendicitis in 16 cases, with moderate to marked fibrosis and granulomas in seven cases. The other four cases had less consistent histological findings. None of the patients developed Crohn's disease during the follow-up interval (median, 37 months).

CONCLUSIONS

Actinomyces can be associated with Crohn's-like appendicitis with marked fibrosis, transmural inflammation, lymphoid hyperplasia, and granulomas.

Loss of SMAD4 protein expression in gastrointestinal and extra-gastrointestinal carcinomas

AIMS

SMAD4 (DPC4) is a tumour suppressor gene that is dysregulated in various tumour types, particularly pancreaticobiliary and gastrointestinal carcinomas. Corresponding loss of protein expression has been reported in approximately 50% of pancreatic and 25% of colonic adenocarcinomas. In the evaluation of carcinoma of unknown primary site, immunohistochemical loss of SMAD4 expression is often used to suggest pancreaticobiliary origin, but there are limited data on the spectrum of SMAD4 expression in carcinomas of other sites. This study evaluates the frequency of SMAD4 loss in a large cohort of carcinomas from diverse anatomical sites.

METHODS AND RESULTS

Immunohistochemistry for SMAD4 was performed on tissue microarrays or whole tissue sections of 1210 carcinomas from various organs: gastrointestinal tract, liver, pancreas/biliary tract, lung, breast, thyroid, kidney, ovary and uterus. Expression was considered lost when there was complete absence of staining in tumour cell nuclei, in the presence of intact staining in non-neoplastic cells. SMAD4 loss was seen in 58% of pancreatic adenocarcinomas, 27% of appendiceal adenocarcinomas, 19% of colorectal adenocarcinomas, 16% of cholangiocarcinomas, 10% of lung adenocarcinomas and <5% of oesophageal, breast, gastric and mucinous ovarian adenocarcinomas. All papillary thyroid, hepatocellular, non-mucinous ovarian, endometrial and renal cell carcinomas showed intact SMAD4 nuclear expression.

CONCLUSION

In addition to pancreaticobiliary, appendiceal and colonic tumours, SMAD4 loss is also seen in a small subset of other carcinomas, specifically breast, lung, oesophageal and gastric adenocarcinomas, all of which are typically CK7-positive, similar to pancreaticobiliary carcinoma. Awareness of SMAD4 loss in these other carcinoma types is helpful in the evaluation of carcinomas of unknown or uncertain primary site.

Perioperative (P) UGT1A1 genotype guided irinotecan (iri) dosing ‘gFOLFIRINOX’ for gastroesophageal adenocarcinoma (GEA)

4050

Background: Complete resection (R0) and pathologic response grade (PRG) correlate with long-term GEA outcome. FOLFIRINOX demonstrated efficacy in advanced GEA; gFOLFIRINOX improved tolerability. We evaluated R0, PRG and tolerability in this pilot P study. Methods: Gastric body (GB) + esophagogastric (EGJ) GEA patients (pts) with ≥T3Nx or TxN+ were enrolled & treated with 4 pre + 4 postoperative biweekly cycles of gFOLFIRINOX (5-FU 2400mg/m2 over 46 hrs; oxaliplatin 85mg/m2; iri: 180mg/m2 for UGT1A1 genotype 6/6, 135mg/m2 for 6/7, 90mg/m2 for 7/7) (+ trastuzumab (T) 6mg/kg then 4mg/kg for HER2+) with prophylactic peg-filgastrim. 1°endpoint R0 resection required 36 pts to assess for a 90% R0 rate (intention to treat (ITT)) with 90% power + 0.05 alpha; ≥30/36 R0 considered positive. Co-1°endpoint was PRG (Becker); 36 pts provided 85% power with 0.05 alpha for a complete (pCR G1a) rate of 16%. 2°endpoints were safety/toxicity, PET response, & R0/PRG by tumor site, histologic subtype, HER2 status, & UGT1A1 genotype. We report efficacy and toxicity data from the neoadjuvant (Neo) portion of the study; postop data & survival outcomes will be presented at the meeting. Results: 4 sites enrolled 36 ITT pts between 2/2014-8/2018; 75% male, median age 66 (range 27-85). All pts completed all 4 cycles of Neo therapy: 10% had any dose reduction of iri (16%/0%/25% by genotype 6/6, 6/7, 7/7); any G3+ toxicity occurred in 35% of pts (32% 6/6, 29% 6/7, 75% 7/7). G3+ toxicity in ≥5% of pts: diarrhea (17.5%; 6/6 21%, 6/7 11%, 7/7 25%), anemia (5%), vomiting (5%). Efficacy is shown in the Table. Of pts going to surgery, both R1 resections were GB linitus. PRG1(a+b) was achieved in 36% of ITT pts, 46% of intestinal type histology. Conclusions: Neo gFOLFIRINOX was tolerable with surrogate efficacy comparable to FLOT. Clinical trial information: NCT02366819. [Table: see text]

Correlation of cytopathology with flow cytometry and histopathology for the diagnosis of hematologic malignancies in young adults presenting with cervical lymphadenopathy

BACKGROUND

Fine-needle aspiration (FNA) is frequently utilized in the diagnostic workup of lymphadenopathy. We evaluated the correlation of cytopathology with flow cytometry and tissue biopsy results and assessed the prevalence of specific malignancies in young adults presenting with cervical lymphadenopathy.

METHODS

Database was searched for cervical lymph node FNA performed by a cytopathologist in patients aged 18-30 years from 2005 to 2017.

RESULTS

Cervical lymph node FNA was performed on 48 patients without prior history of malignancy. Nineteen patients had cytology results only, of which all were interpreted as benign reactive lymph node. None developed subsequent malignancies. The remaining 29 patients had cytology with flow cytometry and/or tissue biopsy results. A benign reactive cytology diagnosis was rendered in 18 (62%) cases, of which 11 had concordant diagnosis on flow cytometry, 2 had tissue biopsy, and 3 had both. Eleven (38%) patients had cytology results concerning for a hematologic malignancy, of which 7 were confirmed by flow cytometry and 3 by both flow cytometry and tissue biopsy. Cervical lymph node FNA has 94.1% sensitivity, 83.3% specificity, 88.9% positive predictive value, and 90.9% negative predictive value. The most common hematologic malignancy in our young adult population presenting with cervical lymphadenopathy was Hodgkin lymphoma.

CONCLUSION

FNA is a useful first-line diagnostic procedure for assessing cervical lymphadenopathy in young adults to allow for better triage of specimens for flow cytometry and/or tissue biopsy concerning for a hematologic malignancy and potentially avoid invasive excisional biopsy in a proportion of cases.

Enteric infections complicating ulcerative colitis

Enteric infections have previously been postulated to play a role in the pathogenesis of inflammatory bowel disease (IBD), however, little evidence exists in the etiologic role of specific enteric infections in the development of IBD. When encountered in the setting of IBD, enteric infections pose a clinical challenge in management given the competing treatment strategies for infectious conditions and autoimmune disorders. Here we present the case of a young male with enteric infections complicating a new diagnosis of IBD. Our patient's initial clinical presentation included diagnoses of Klebsiella oxytoca isolation and Clostridium difficile infection. Directed therapies to include withdrawal of antibiotics and fecal microbiota transplantation were performed without resolution of clinical symptoms. Given persistence of symptoms and active colitis, the patient was diagnosed with ulcerative colitis (UC), requiring treatments directed at severe UC to include cyclosporine therapy. The finding of multiple enteric infections in a newly presenting patient with IBD is an unexpected finding that has treatment implications.

Targeted Therapies for Targeted Populations: Anti-EGFR Treatment for EGFR-Amplified Gastroesophageal Adenocarcinoma

Previous anti-EGFR trials in unselected patients with gastroesophageal adenocarcinoma (GEA) were resoundingly negative. We identified EGFR amplification in 5% (19/363) of patients at the University of Chicago, including 6% (8/140) who were prospectively screened with intention-to-treat using anti-EGFR therapy. Seven patients received ≥1 dose of treatment: three first-line FOLFOX plus ABT-806, one second-line FOLFIRI plus cetuximab, and three third/fourth-line cetuximab alone. Treatment achieved objective response in 58% (4/7) and disease control in 100% (7/7) with a median progression-free survival of 10 months. Pretreatment and posttreatment tumor next-generation sequencing (NGS), serial plasma circulating tumor DNA (ctDNA) NGS, and tumor IHC/FISH for EGFR revealed preexisting and/or acquired genomic events, including EGFR-negative clones, PTEN deletion, KRAS amplification/mutation, NRAS, MYC, and HER2 amplification, and GNAS mutations serving as mechanisms of resistance. Two evaluable patients demonstrated interval increase of CD3+ infiltrate, including one who demonstrated increased NKp46+, and PD-L1 IHC expression from baseline, suggesting an immune therapeutic mechanism of action. EGFR amplification predicted benefit from anti-EGFR therapy, albeit until various resistance mechanisms emerged.Significance: This paper highlights the role of EGFR inhibitors in EGFR-amplified GEA-despite negative results in prior unselected phase III trials. Using serial ctDNA and tissue NGS, we identified mechanisms of primary and acquired resistance in all patients, as well as potential contribution of antibody-dependent cell-mediated cytotoxicity to their clinical benefit. Cancer Discov; 8(6); 696-713. ©2018 AACR.See related commentary by Strickler, p. 679This article is highlighted in the In This Issue feature, p. 663.

Gastric pyloric gland adenoma: a multicentre clinicopathological study of 67 cases

AIMS

There is limited information regarding the clinicopathological and immunohistochemical characteristics of gastric pyloric gland adenomas (PGAs).

METHODS AND RESULTS

Sixty-seven cases of gastric PGA from 57 patients were analysed. PGAs occurred with similar frequency in men and women (47.4 and 52.6%, respectively), with a mean age of 66 years. Most presented in the gastric body/fundus (67.2%). Fifteen cases (22.4%) developed against a background of autoimmune gastritis (AIG), whereas normal mucosa was seen in 35.8%. Only 16.4% (11 cases) developed in patients with a genetic predisposition, most commonly familial adenomatous polyposis. Low-grade lesions had a mean size of 1.5 cm, while PGAs with high-grade dysplasia (HGD) or adenocarcinoma had a mean size of 3.5 cm (P < 0.001) and more commonly showed tubulovillous architecture (50.0 versus 25.6% in low-grade dysplasia; P = 0.040). Most PGAs (61.2%) co-expressed mucin (MUC)5AC and MUC6 (mixed type), which was associated significantly with HGD or adenocarcinoma (P = 0.013). AIG was also associated with HGD (P = 0.027), but genetic predisposition did not correlate with the grade of dysplasia (P = 0.793). The recurrence rate of PGA was similar for high- (11.8%) and low-grade lesions (7.4%) (P = 0.624).

CONCLUSIONS

The risk of HGD increases with the size of PGA, tubulovillous architecture and the presence of AIG as well as mixed immunophenotype. As the overall local recurrence rate is less than 10%, PGAs may be treated conservatively, but they should be excised completely if possible, particularly if they are large or show high-grade features.

Colorectal Carcinomas With Isolated Loss of PMS2 Staining by Immunohistochemistry

Context.—

Isolated loss of PMS2 staining is an uncommon immunophenotype in colorectal carcinomas, accounting for approximately 4% of tumors with microsatellite instability. Limited information regarding these tumors is available in the literature.

Objective.—

To compare the clinicopathologic features of colorectal carcinomas with isolated PMS2 loss by immunohistochemistry to those with other forms of mismatch repair deficiency.

Design.—

Ninety-three colorectal carcinomas with isolated PMS2 loss by immunohistochemistry and 193 with other forms of mismatch repair deficiency were identified. Forty (43%) of the isolated PMS2 loss cases and 35 control cases (18%) had a known germline mutation or a clinical diagnosis of Lynch syndrome.

Results.—

Overall, isolated PMS2-loss tumors occurred in significantly younger patients (P &lt; .001) and in fewer female patients (P = .006). These tumors were significantly less likely to be right-sided (P = .001), high-grade (P = .01), or display histologic features of microsatellite instability (P &lt; .001). The isolated PMS2-loss group also exhibited increased odds of disease-specific death (odds ratio [OR], 3.09; 95% CI, 1.41–6.85; P = .007). When the analysis was restricted to germline mutation/Lynch syndrome cases and controls, no significant differences were detected for age, sex, tumor location, tumor grade, histologic features, or distant metastases, although a trend toward increased odds of disease-specific death in the isolated PMS2-loss group was evident (OR, 3.87; 95% CI, 0.89–27.04; P = .10).

Conclusions.—

Unusual clinicopathologic features observed in colorectal carcinomas with isolated PMS2 loss are likely related to the high proportion of cases caused by germline mutations. Isolated PMS2-loss tumors may demonstrate more aggressive behavior than other tumors with microsatellite instability, but larger studies are needed to investigate that possibility further.

Genomic Heterogeneity as a Barrier to Precision Medicine in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinoma (GEA) is a lethal disease where targeted therapies, even when guided by genomic biomarkers, have had limited efficacy. A potential reason for the failure of such therapies is that genomic profiling results could commonly differ between the primary and metastatic tumors. To evaluate genomic heterogeneity, we sequenced paired primary GEA and synchronous metastatic lesions across multiple cohorts, finding extensive differences in genomic alterations, including discrepancies in potentially clinically relevant alterations. Multiregion sequencing showed significant discrepancy within the primary tumor (PT) and between the PT and disseminated disease, with oncogene amplification profiles commonly discordant. In addition, a pilot analysis of cell-free DNA (cfDNA) sequencing demonstrated the feasibility of detecting genomic amplifications not detected in PT sampling. Lastly, we profiled paired primary tumors, metastatic tumors, and cfDNA from patients enrolled in the personalized antibodies for GEA (PANGEA) trial of targeted therapies in GEA and found that genomic biomarkers were recurrently discrepant between the PT and untreated metastases. Divergent primary and metastatic tissue profiling led to treatment reassignment in 32% (9/28) of patients. In discordant primary and metastatic lesions, we found 87.5% concordance for targetable alterations in metastatic tissue and cfDNA, suggesting the potential for cfDNA profiling to enhance selection of therapy.Significance: We demonstrate frequent baseline heterogeneity in targetable genomic alterations in GEA, indicating that current tissue sampling practices for biomarker testing do not effectively guide precision medicine in this disease and that routine profiling of metastatic lesions and/or cfDNA should be systematically evaluated. Cancer Discov; 8(1); 37-48. ©2017 AACR.See related commentary by Sundar and Tan, p. 14See related article by Janjigian et al., p. 49This article is highlighted in the In This Issue feature, p. 1.

Use of volumetric laser endomicroscopy for dysplasia detection at the gastroesophageal junction and gastric cardia

AIM

To determine specific volumetric laser endomicroscopy (VLE) imaging features associated with neoplasia at the gastroesophageal junction (GEJ) and gastric cardia.

METHODS

During esophagogastroduodenoscopy for patients with known or suspected Barrett’s esophagus, VLE was performed before biopsies were taken at endoscopists’ discretion. The gastric cardia was examined on VLE scan from the GEJ (marked by top of gastric folds) to 1 cm distal from the GEJ. The NinePoints VLE console was used to analyze scan segments for characteristics previously found to correlate with normal or abnormal mucosa. Glands were counted individually. Imaging features identified on VLE scan were correlated with biopsy results from the GEJ and cardia region.

RESULTS

This study included 34 cases. Features characteristic of the gastric cardia (gastric rugae, gastric pit architecture, poor penetration) were observed in all (100%) scans. Loss of classic gastric pit architecture was common and there was no difference between those with neoplasia and without (100% vs 74%, P = NS). The abnormal VLE feature of irregular surface was more often seen in patients with neoplasia than those without (100% vs 18%, P < 0.0001), as was heterogeneous scattering (86% vs 41%, P < 0.005) and presence of anomalous glands (100% vs 59%, P < 0.05). The number of anomalous glands did not differ between individual histologic subgroups (ANOVA, P = NS).

CONCLUSION

The transition from esophagus to gastric cardia is reliably identified on VLE. Histologically abnormal cardia mucosa produces abnormal VLE features. Optical coherence tomography algorithms can be expanded for use at the GEJ/cardia.

Critical role of microbiota within cecal crypts on the regenerative capacity of the intestinal epithelium following surgical stress

Cecal crypts represent a unique niche that are normally occupied by the commensal microbiota. Due to their density and close proximity to stem cells, microbiota within cecal crypts may modulate epithelial regeneration. Here we demonstrate that surgical stress, a process that invariably involves a short period of starvation, antibiotic exposure, and tissue injury, results in cecal crypt evacuation of their microbiota. Crypts devoid of their microbiota display pathophysiological features characterized by abnormal stem cell activation as judged by leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) staining, expansion of the proliferative zone toward the tips of the crypts, and an increase in apoptosis. In addition, crypts devoid of their microbiota display loss of their regenerative capacity as assessed by their ability to form organoids ex vivo. When a four-member human pathogen community isolated from the stool of a critically ill patient is introduced into the cecum of mice with empty crypts, crypts become occupied by the pathogens and further disruption of crypt homeostasis is observed. Fecal microbiota transplantation restores the cecal crypts' microbiota, normalizes homeostasis within crypts, and reestablishes crypt regenerative capacity. Taken together, these findings define an emerging role for the microbiota within cecal crypts to maintain epithelial cell homeostasis in a manner that may enhance recovery in response to the physiological stress imposed by the process of surgery.

NEW & NOTEWORTHY

This study provides novel insight into the process by which surgical injury places the intestinal epithelium at risk for colonization by pathogenic microbes and impairment of its regenerative capacity via loss of its microbiota. We show that fecal transplant restores crypt homeostasis in association with repopulation of the microbiota within cecal crypts.

Anti-EGFR treatment for EGFR-amplified gastroesophageal adenocarcinoma

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Background: Gastroesophageal cancer (GEC) is a global health problem. Multiple phase III anti-EGFR trials of unselected metastatic GEC patients (pts) were negative, yet subset analyses suggested potential benefit in pts with EGFR amplification (amp). We sought to quantify the incidence of EGFR amp in metastatic/recurrent GEC pts compared to the locally advanced TCGA rate, treat them with EGFR antagonists, quantify response/duration, and assess for mechanisms of action and resistance (MOA, MOR). Methods: 106 stage IV GEC pts in any therapy (tx) line (L) were prospectively screened for EGFR amp between 9/1/14-8/31/16 at a single site using tumor next generation sequencing (NGS). EGFR amp samples were then assessed by FISH, immunohistochemistry (IHC) and mass spectroscopy (MS) to confirm. Pts received 1L ABT-806 (1/4) or 2L+ cetux (3/4) monoclonal anti-EGFR antibodies, in combination with chemotherapy if 1L or 2L (2/4), or as monotherapy for 3L+ (2/4). Pts were followed for response (ORR) and disease control (DCR). Pre and post-treatment NGS, serial ctDNA, and EGFR/PD-L1 FISH/IHC/MS were obtained to monitor for MOA and MOR to tx. Results: Six (5.7%) pts harbored EGFR amp tumors with copies/cell ranging 54-167. Four eligible pts received >1 dose of tx with monoclonal anti-EGFR therapy: 1 FOLFOX-ABT-806 (1L), 1 FOLFIRI-cetux (2L), and 2 cetux alone (3L, 4L); ORR was 100% (4/4) by RECIST, respectively (-70%, -65%, -77%, -43%). All 3 cetux treated pts developed classic rash, which disappeared when/if progression (2/3). The 4-month DCR was 75% (3/4). No pts showed PD-L1 staining pre/post therapy. Upon progression, the 2L pt acquired de novo PTEN exon 6 deletion after 10 months, while basal NRAS mutated and HER2 amp ctDNA clones had expanded in the 4L pt after 4 months of monotherapy. Conclusions: EGFR amp incidence was similar to TCGA. Despite large negative trials with EGFR antagonists for GEC, EGFR amp predicted benefit (100%) from anti-EGFR tx, including monotherapy in 50%, albeit until various resistance mechanisms emerged, including HER2, RAS, and PTEN/AKT pathway activation. No PD-L1 expression was observed pre/post treatment, consistent with our previous data showing that EGFR-amplified cases trend towards a ‘non-T cell-inflamed’ phenotype. Clinical trial information: NCT01416714 / NCT02213289.

Predictors of Lymph Node Metastasis in Western Early Gastric Cancer

BACKGROUND

The application of endoscopic and local resection for early gastric cancer (EGC) is limited by the risk of regional lymph node (LN) metastasis. We sought to determine the incidence and predictors of LN metastasis in a contemporary cohort of Western patients with early gastric cancer.

METHODS

Sixty-seven patients with pT1 gastric adenocarcinoma underwent radical surgery without neoadjuvant therapy at our institution between 1995 and 2011, and clinicopathologic factors predicting LN metastasis were analyzed.

RESULTS

LN metastases were present in 15/67 (22 %) pT1 tumors, including 1/23 (4 %) T1a tumors and 14/44 (32 %) T1b tumors. Tumor size, site, degree of differentiation, macroscopic tumor sub-classification, perineural invasion status, and depth of submucosal tumor penetration did not predict LN metastasis. The presence of lymphovascular invasion (LVI) and positive nodal status by endoscopic ultrasound (EUS) were the only factors that predicted LN metastasis on multivariate analysis. T1a tumors without LVI had a 0 % rate of positive LN, whereas T1b tumors with LVI had a 64.3 % rate of positive LN.

CONCLUSIONS

EGC limited to the mucosa, without evidence of LVI, and N0 on EUS, may be considered for limited resection. However, any EGC with submucosal invasion, LVI, or positive nodes on EUS should undergo radical resection with lymphadenectomy.

Familial Gastric Cancers

Although the majority of gastric carcinomas are sporadic, approximately 10% show familial aggregation, and a hereditary cause is determined in 1%-3% cases. Of these, hereditary diffuse gastric cancer is the most recognized predisposition syndrome. Although rare, the less commonly known syndromes also confer a markedly increased risk for development of gastric cancer. Identification and characterization of these syndromes require a multidisciplinary effort involving oncologists, surgeons, genetic counselors, biologists, and pathologists. This article reviews the molecular genetics, clinical and pathologic features, surveillance guidelines, and preventive measures of common and less common hereditary gastric cancer predisposition syndromes.

Poorly Differentiated Thyroid Carcinoma

Poorly differentiated thyroid carcinoma (PDTC) has been recognized for the past 30 years as an entity showing intermediate differentiation and clinical behavior between well-differentiated thyroid carcinomas (ie, papillary thyroid carcinoma and follicular thyroid carcinoma) and anaplastic thyroid carcinoma; however, there has been considerable controversy around the definition of PDTC. In this review, the evolution in the definition of PDTC, current diagnostic criteria, differential diagnoses, potentially helpful immunohistochemical studies, and molecular alterations are discussed with the aim of highlighting where the diagnosis of PDTC currently stands.

Lymph node extramedullary hematopoiesis in breast cancer patients receiving neoadjuvant therapy: a potential diagnostic pitfall

Extramedullary hematopoiesis (EMH) develops as a compensatory mechanism associated with hematologic processes but it may occur in association with chemotherapy. Three cases of EMH arising in axillary lymph nodes following neoadjuvant therapy for breast carcinoma are reported herein. Three women ranging in age from 41 to 47 years presented with unilateral breast masses measuring 0.6 to 4.0 cm in greatest dimension and were diagnosed with infiltrating ductal carcinoma, grade III by core needle biopsies. Two of the tumors were triple negative and one was estrogen receptor positive. All patients subsequently received neoadjuvant therapy followed by lumpectomies. No residual carcinoma was identified in postchemotherapy breast resection specimens. One patient underwent a sentinel lymph node procedure, the second patient an axillary lymph node dissection, and the third patient had a core biopsy of an enlarged axillary lymph node. The patient that underwent axillary lymph node dissection had metastatic carcinoma in one of her lymph nodes. Foci of EMH consisting of myeloid, erythroid, and megakaryocytic precursors were present within the nodal parenchyma and/or subcapsular sinuses of axillary lymph nodes of all three cases. Megakaryocytes were immunoreactive with factor VIII, erythroid elements with Glycophorin and myeloid precursors with myeloperoxidase. With increasing use of neoadjuvant therapy for breast carcinoma, EMH within lymph nodes is more likely to be encountered. Hematopoietic precursors present in lymph nodes may potentially be misdiagnosed as metastatic tumor cells, particularly as lobular carcinoma or metaplastic carcinoma. Therefore, caution should be exercised when evaluating axillary lymph nodes in the clinical setting of neoadjuvant therapy for breast carcinoma.