Lymphocytic esophagitis: a histologic pattern with emerging clinical ramifications

Histopathologic Manifestations of Immune Checkpoint Inhibitor Therapy-Associated Gastrointestinal Tract Injury: A Practical Review

Immune checkpoint inhibitors have revolutionized the management of many advanced cancers by producing robust remissions. They mostly target two immune regulatory pathways: cytotoxic T lymphocyte antigen-4 and programmed death-1 or its ligand. However, a flip side is the immune-related adverse events (irAEs) commonly affecting the gastrointestinal (GI) tract that can cause treatment interruptions or discontinuation. This practical review discusses the clinical and histopathologic findings of irAEs encountered in the luminal GI tract, along with histopathologic differentials that can mimic varied inflammatory, infectious, or other medication-associated etiologies and the importance of clinico-pathologic correlation for an accurate diagnosis.

Lymphocytic oesophagitis: diagnosis and management

Lymphocytic oesophagitis is a rare inflammatory condition that was first described in 2006. Although it is being increasingly diagnosed, it remains poorly described and characterised. There is limited research on the natural history, diagnosis and management of this condition. The most common presenting symptoms are dysphagia, chest pain and heartburn. Endoscopic features can mimic eosinophilic oesophagitis. International consensus is needed to secure a histological definition, to agree on an endoscopic severity scoring system and to determine an appropriate management algorithm. This review summarises the main evidence for the diagnosis and management of lymphocytic oesophagitis, thus setting the scene for the future directions needed to improve the management of this condition.

[Inflammatory bowel diseases and upper gastrointestinal tract]

Inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis are inflammatory diseases with a flare-up evolution and an unknown etiology. Inflammatory lesions of the upper gastrointestinal tract are more and more often described in Crohn's disease and ulcerative colitis. The aim of this article was to review the inflammatory lesions of the esophagus, stomach and duodenum currently described in the IBD.

Development and technical validation of an artificial intelligence model for quantitative analysis of histopathologic features of eosinophilic esophagitis

Background

In an attempt to provide quantitative, reproducible, and standardized analyses in cases of eosinophilic esophagitis (EoE), we have developed an artificial intelligence (AI) digital pathology model for the evaluation of histologic features in the EoE/esophageal eosinophilia spectrum. Here, we describe the development and technical validation of this novel AI tool.

Methods

A total of 10 726 objects and 56.2 mm² of semantic segmentation areas were annotated on whole-slide images, utilizing a cloud-based, deep learning artificial intelligence platform (Aiforia Technologies, Helsinki, Finland). Our training set consisted of 40 carefully selected digitized esophageal biopsy slides which contained the full spectrum of changes typically seen in the setting of esophageal eosinophilia, ranging from normal mucosa to severe abnormalities with regard to each specific features included in our model. A subset of cases was reserved as independent “test sets” in order to assess the validity of the AI model outside the training set. Five specialized experienced gastrointestinal pathologists scored each feature blindly and independently of each other and of AI model results.

Results

The performance of the AI model for all cell type features was similar/non-inferior to that of our group of GI pathologists (F1-scores: 94.5–94.8 for AI vs human and 92.6–96.0 for human vs human). Segmentation area features were rated for accuracy using the following scale: 1. “perfect or nearly perfect” (95%–100%, no significant errors), 2. “very good” (80%–95%, only minor errors), 3. “good” (70%–80%, significant errors but still captures the feature well), 4. “insufficient” (less than 70%, significant errors compromising feature recognition). Rating scores for tissue (1.01), spongiosis (1.15), basal layer (1.05), surface layer (1.04), lamina propria (1.15), and collagen (1.11) were in the “very good” to “perfect or nearly perfect” range, while degranulation (2.23) was rated between “good” and “very good”.

Conclusion

Our newly developed AI-based tool showed an excellent performance (non-inferior to a group of experienced GI pathologists) for the recognition of various histologic features in the EoE/esophageal mucosal eosinophilia spectrum. This tool represents an important step in creating an accurate and reproducible method for semi-automated quantitative analysis to be used in the evaluation of esophageal biopsies in this clinical context.

Histologic Findings in Mucosa and Muscularis Propria Biopsied During Peroral Endoscopic Myotomy in Patients With Achalasia

Background

Peroral endoscopic myotomy (POEM) has been increasingly used to treat achalasia. Previous studies have reported high frequency of muscular eosinophilic infiltration in achalasia. Esophageal mucosal changes in achalasia have only been studied in esophagectomy specimens. Cardia mucosal changes in achalasia have not been reported previously. We aimed to further characterize the esophageal, gastric cardia, and muscularis propria changes in achalasia.

Methods

This was a pilot study. Patients with clinically and radiographically confirmed achalasia who underwent POEM were enrolled in the study. Mucosal biopsies were taken 1 cm proximal and 1 cm distal to the gastroesophageal junction, and muscularis propria biopsies were taken from the mid esophagus. Tissues were submitted for histological evaluation.

Results

Eighteen patients (10 male and eight female, mean age: 60.7 (standard deviation (SD): 13) years) were enrolled in this pilot study. Nine patients had type II achalasia, two type III, one type I, five esophageal gastric outlet obstruction, and one unspecific type achalasia. The mean duration of symptoms prior to POEM was 79 (range 1 - 480) months. All patients had a dilated esophagus on examination, but no endoscopic evidence of Barrett's esophagus. Esophageal, gastric cardia, and muscular biopsies were performed in 17, 13, and 17 patients, respectively. Basal hyperplasia, spongiosis, ballooning, and parakeratosis were seen in 92.3%, 100%, 100%, and 76.5% of cases, respectively. Intraepithelial lymphocytosis was seen in 70.5% of cases, and active esophagitis was seen in 23.5% of case. Six (35.3%) cases had few intraepithelial eosinophils, but none of them had > 15 eosinophils per high power field. Histologic findings in gastric cardia mucosa included carditis (69.2%), H. pylori gastritis (7.6%), and reactive gastropathy (15.4%). One case (7.6%) showed low-grade dysplasia arising from intestinal metaplasia in the cardia. Absence of ganglion cells in the muscular biopsies was noted in 88.2% of cases, and the remaining two showed rare residual ganglion cells with ganglionitis in one case (5.8%). Muscular atrophy and interstitial fibrosis were observed in 52.9% and 82.3% of the cases, respectively. Two cases (11.7%) had eosinophilic inflammation in the muscularis propria and one of them was accompanied by lymphocytic inflammation.

Conclusions

Muscular biopsies in our study revealed loss of ganglion cells, supporting the view that achalasia is a primary esophageal disease with ganglion cell depletion. Squamous mucosa in achalasia showed changes mimicking reflux and lymphocytic esophagitis. Cardia mucosa in achalasia patients often were inflamed and uncommonly showed intestinal metaplasia and glandular dysplasia.

Pathologic Manifestations of Gastrointestinal and Hepatobiliary Injury in Immune Checkpoint Inhibitor Therapy

CONTEXT.—

Immune checkpoint inhibitors (CPIs), including cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors and the programmed death receptor-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors, are being increasingly used for treating many advanced malignancies. However, CPI therapy is also associated with gastrointestinal and hepatobiliary adverse effects.

OBJECTIVES.—

To review the adverse effects of CPI therapy on the gastrointestinal tract and hepatobiliary system. To describe histopathologic patterns and discuss differential diagnostic considerations in the diagnosis of CPI injuries.

DATA SOURCES.—

Published peer-reviewed literature in the English language and personal experience in the diagnosis of CPI injuries.

CONCLUSIONS.—

The pathologic manifestations of CPI therapy-induced gastrointestinal and hepatobiliary injury are broad. The patterns of esophageal CPI injury include lymphocytic inflammation and ulcerative esophagitis, while those of gastric injury include chronic active gastritis, lymphocytic gastritis, focal enhancing gastritis, and periglandular inflammation. The duodenal injury may present as duodenitis with villous blunting and granulomas. We also noticed active colitis, microscopic colitis, chronic active colitis, increased apoptosis, ischemic colitis, and nonspecific inflammatory reactive changes in colonic injuries. The reported histologic features of hepatobiliary injuries are panlobular hepatitis, centrilobular necrosis, portal inflammation with bile duct injury, steatosis, nodular regenerative hyperplasia, and secondary sclerosing cholangitis. In summary, we discuss the pathologic features and differential diagnosis of CPI therapy-induced gastrointestinal and hepatobiliary injury. Recognition of CPI injury is important to determine the proper management that often includes cessation of CPI therapy, and administration of steroids or other immunosuppressive agents, based on severity of injury.

Histopathology of Gastrointestinal Immune-related Adverse Events: A Practical Review for the Practicing Pathologist

Immune checkpoint inhibitors target checkpoint proteins with the goal of reinvigorating the host immune system and thus restoring antitumor response. With the dramatic increase in the use of checkpoint inhibitors for cancer treatment, surgical pathologists have assumed a major role in predicting the therapeutic efficacy (score based on programmed cell death ligand 1 immunohistochemistry and mismatch repair protein loss) as well as diagnosing the complications associated with these medications. Immune-related adverse events (irAEs) manifest as histologic changes seen in both the upper and lower gastrointestinal tract, and when viewed in isolation, may be morphologically indistinguishable from a wide range of diseases including infections, celiac disease, and inflammatory bowel disease, among others. Evaluation of biopsies from both the upper and lower gastrointestinal tract can aid in the distinction of gastrointestinal irAEs from their mimics. In the liver, the histologic changes of hepatic irAEs overlap with de novo diseases associated with hepatitic and cholangitic patterns of injury. The diagnosis of irAEs requires communication and collaboration from the pathologist, oncologist, and gastroenterologist. This review provides a background framework and illustrates the histologic features and differential diagnosis of gastrointestinal and hepatic irAEs.

Non gastro-esophageal reflux disease related esophagitis: an overview with a histologic diagnostic approach

Several pathological conditions, other than gastro-esophageal reflux disease and its complications, can affect the esophagus. While some of these can present with unspecific lesions (i.e. ulcers and epithelial damage) and require clinico-pathological correlation for diagnosis (i.e. drug-induced esophagitis and corrosive esophagitis) other conditions show distinctive histological lesions which enable the pathologist to reach the diagnosis (i.e. some specific infectious esophagites and Crohn's disease). In this context eosinophilic esophagitis is the condition which has been increasingly studied in the last two decades, while lymphocytic esophagitis, a relatively new entity, still represents an enigma. This overview will focus on and describe histologic lesions which allow pathologists to differentiate between these conditions.

Upper gastrointestinal tract involvement of pediatric inflammatory bowel disease: A pathological review

Upper gastrointestinal (UGI) tract involvement of inflammatory bowel disease (IBD) is commonly seen in pediatric patients. Upper endoscopy is included in the routine workup of children with suspected IBD to enhance the diagnosis and management of these patients. Currently, childhood IBD is classified into ulcerative colitis (UC), atypical UC, Crohn’s disease (CD) and IBD unclassified. Histologic confirmation of UGI tract involvement, in particular the presence of epithelioid (non-caseating) granulomas, is helpful in confirming the diagnosis of IBD and its classification. Herein, we reviewed selected IBD-associated UGI tract manifestations in children. Lymphocytic esophagitis, seen predominantly in CD, is histologically characterized by increased intraepithelial lymphocytes (> 20 in one high-power field) in a background of mucosal injury with absence of granulocytes. Focally enhanced gastritis is a form of gastric inflammation in pediatric IBD marked by a focal lymphohistiocytic pit inflammation with or without granulocytes and plasma cells in a relatively normal background gastric mucosa. Duodenal inflammation seen in children with IBD includes cryptitis, villous flattening, increased intraepithelial lymphocytes, and lamina propria eosinophilia. Finally, epithelioid granulomas not associated with ruptured gland/crypt are a diagnostic feature of CD. The clinicopathologic correlation and differential diagnosis of each microscopic finding are discussed. Clinicians and pathologists should be cognizant of the utility and limitations of these histologic features.

Clinical, endoscopic, and histologic characteristics of lymphocytic esophagitis: a systematic review

OBJECTIVE

Lymphocytic esophagitis (LyE) is a novel, yet poorly described, clinicopathologic entity. The aim of this systematic review was to characterize the demographic, clinical, endoscopic, and histologic features of LyE in observational studies of adult and pediatric patients.

DESIGN

We searched the Embase, MEDLINE, and SCOPUS databases for relevant studies in 2018. Two authors reviewed and extracted data from studies that met the inclusion and exclusion criteria.

RESULTS

We identified 20 studies for analysis of demographic, clinical, and endoscopic features of LyE. The mean age ranged from 9 to 67 years. When pooled, there were 231 (52.7%) patients with LyE that were female. The most common presenting symptom was dysphagia reported in 191 (48.8%) patients. On endoscopy, most patients with LyE tended to have abnormal findings (69.0%), which included erosive esophagitis, multiple esophageal rings, linear furrows, and narrow-caliber esophagus. In the 31 studies used to assess the histologic definition, the cut-off number of intraepithelial lymphocytes (IELs) was reported in 16 (51.6%) studies, peripapillary IEL specification in 18 (58.1%) studies, and presence of spongiosis in 6 (19.4%) studies.

CONCLUSION

We identified a spectrum of demographic, clinical, and endoscopic findings characteristic of patients with LyE. A consensus on the diagnostic criteria of LyE is required.

Lymphocytic esophagitis: an update on histologic diagnosis, endoscopic findings, and natural history

Lymphocytic esophagitis is a histologic pattern of injury characterized by increased intraepithelial lymphocytes (>20/high-power field) with rare, or absent granulocytes. Lymphocytes tend to be more numerous in the peripapillary epithelium, and are often associated with evidence of mucosal injury, edema, and scattered dyskeratotic cells. More than a decade following its original description, lymphocytic esophagitis remains an enigmatic entity with variable clinical presentations, associated disorders, etiologies, treatment, and natural history. Most of the confusion regarding the clinical significance of this disorder stems from its diagnostic criteria: lymphocytic esophagitis is currently defined based entirely on histologic criteria, despite the common occurrence of lymphocytosis in a variety of unrelated inflammatory conditions of the esophagus. The goal of this review is to summarize the literature regarding lymphocytic esophagitis and focus on key clinicopathologic features that distinguish it from other esophageal disorders that can show increased numbers of intraepithelial lymphocytes.