A Pattern-Based Approach to Hepatic Infections.

The evaluation of liver biopsies for infection can be a challenging and frustrating situation for diagnostic pathologists as well as clinicians. Patients often present with nonspecific symptoms, such as fever and elevated transaminases, leading to a broad differential diagnosis that typically includes malignancy and noninfectious inflammatory diseases in addition to infections. A pattern-based histologic approach can be extremely helpful in both making a diagnosis and guiding the next steps for the evaluation of the pathology specimen as well as the patient. This review discusses several of the more commonly encountered histologic patterns associated with hepatic infectious diseases, the most common pathogens with which they are associated, and helpful ancillary studies.

Crohn's Disease Features in Anastomotic Biopsies from Patients With and Without Crohn's Disease: Diagnostic and Prognostic Value.

Endoscopic evidence of disease activity is a critical predictor of clinical relapse in patients with Crohn's disease (CD), and histologic disease activity is evolving as a similarly important end point for patient management. However, classical morphologic features of CD may overlap with postoperative inflammatory changes, confounding the evaluation of anastomotic biopsies. There is a clear unmet need for better characterization of diagnostic and clinically significant histologic features of CD in these surgically altered sites. We evaluated ileocolonic and colocolonic/rectal anastomotic biopsies performed at 3 academic institutions in patients with and without CD. The biopsies were blindly assessed for CD histologic features and correlated to clinical and endoscopic characteristics. In CD patients, the presence of each feature was correlated with the subsequent clinical exacerbation or relapse. We obtained anastomotic biopsies from 208 patients, of which 109 were operated on for CD and 99 for another indication (neoplasia [80%], diverticular disease (11%), and other [9%]). Mean time since surgery was 10 years (0-59; 14 years for CD [1-59], 6 years for non-CD [0-33]). Endoscopic inflammation was noted in 52% of cases (68% for CD and 35% for non-CD). Microscopic inflammation was present in 74% of cases (82% for CD and 67% for non-CD). Only discontinuous lymphoplasmacytosis (P < .001) and pyloric gland metaplasia (P = .04) occurred significantly more often in CD patients. However, none of the histologic features predicted clinical disease progression. In subset analysis, the presence of histologic features of CD in nonanastomotic biopsies obtained concurrently in CD patients was significantly associated with relapse (P = .03). Due to extensive morphologic overlap between CD and postoperative changes and the lack of specific histologic features of relapse, biopsies from anastomotic sites are of no value in predicting clinical CD progression. Instead, CD activity in biopsies obtained away from anastomotic sites should be used for guiding endoscopic sampling and clinical management.

Adenomatoid tumours of the gastrointestinal tract - a case-series and review of the literature.

AIMS: Adenomatoid tumours are mesothelial-derived benign neoplasms with a predilection for the genital tract. Extragenital sites are rare and can cause significant diagnostic challenges. Herein, we describe the clinicopathological features of a cohort of adenomatoid tumours involving the gastrointestinal tract and liver in order to more clearly characterise their histological findings and aid in diagnosis. METHODS AND RESULTS: The pathology databases at four institutions were searched for adenomatoid tumours involving the gastrointestinal tract or liver, yielding eight cases. Available clinicoradiological and follow-up data were collected from the medical records. Six tumours were incidentally discovered during imaging studies or at the time of surgical exploration for unrelated conditions; presenting symptoms were unknown in two patients. Histologically, the tumours were well-circumscribed, although focal ill-defined borders were present in four cases. No infiltration of adjacent structures was identified. Architectural heterogeneity was noted in five (63%) tumours; an adenoid pattern often predominated. The neoplastic cells were flattened to cuboidal with eosinophilic cytoplasm. Cytoplasmic vacuoles mimicking signet ring-like cells were present in five (63%) cases. Three (38%) cases showed involvement of the mesothelium with reactive mesothelial hyperplasia. Cytological atypia or increased mitotic activity was not identified. The surrounding stroma ranged from oedematous/myxoid to densely hyalinised. Immunohistochemistry confirmed mesothelial origin in all cases evaluated. No patients developed recurrence of disease. CONCLUSIONS: The current study evaluates the clinicopathological findings in a collective series of gastrointestinal and hepatic adenomatoid tumours, correlating with those described in individually reported cases. We highlight common histological features and emphasise variable findings that could mimic a malignant neoplasm.

Gastrointestinal, hepatic, and pancreatobiliary involvement by plasma cell neoplasms: clinicopathologic correlations in a retrospective cohort of 116 cases.

AIMS: Plasma cell neoplasms (PCNs) may involve the gastrointestinal (GI) tract in two forms: plasmacytoma (PC), an isolated lesion that lacks marrow involvement, and extramedullary myeloma (EMM). However, previous literature on PCNs involving the GI tract, liver, and pancreas is limited. We evaluated the clinicopathologic features of the largest series of GI PCNs to date. METHODS AND RESULTS: Six institutional archives were searched for GI, liver, and pancreas cases involved with PCNs. Medical records were reviewed for clinical and imaging features. Histopathologic features evaluated included involved organ, tumor grade, and marrow involvement. Overall, 116 cases from 102 patients were identified. The tumors most presented as incidental findings (29%). The liver was most involved (47%), and masses/polyps (29%) or ulcers (21%) were the most common findings. Most cases had high-grade morphology (55%). The majority (74%) of GI PCNs were classified as EMM due to the presence of marrow involvement at some point during the disease course, occurring within a year of marrow diagnosis in 46% of patients. PC was classified in 26% of patients due to the lack of marrow involvement. Most (70%) patients died from disease within 10 years (median 14.1) of diagnosis and more than half (58%) died within 6 months. CONCLUSION: PC and EMM involving the GI tract, liver, and pancreas have a wide range of clinicopathologic presentations. Tumors may occur virtually anywhere in the GI tract or abdomen and may precede the diagnosis of marrow involvement. Both GI PC and EMM are associated with a poor prognosis.

Diagnostic challenges of focal nodular hyperplasia: interobserver variability, accuracy, and the utility of glutamine synthetase immunohistochemistry.

AIMS: The diagnosis of focal nodular hyperplasia (FNH) and the interpretation of glutamine synthetase (GS) staining can be challenging on biopsies. We aimed to evaluate the reproducibility of needle biopsy diagnosis of FNH, the effect of GS immunohistochemistry on FNH diagnosis, and which histological features are most useful for the diagnosis of FNH. METHODS AND RESULTS: The study included virtual needle biopsies generated from 75 resection specimens (30 FNHs, 15 hepatocellular adenomas, 15 hepatocellular carcinomas, and 15 non-lesional liver specimens). Pathologists were reasonably accurate (83.1%) in the diagnosis of FNH with haematoxylin and eosin alone. Ductular reaction and nodularity had the highest sensitivity for a diagnosis of FNH (88.1% and 82.2%, respectively), whereas central scar was the most specific feature (90.6%). The presence of two or more of the classic histological features had 89.6% sensitivity and 86.2% specificity for a diagnosis of FNH. Diagnostic accuracy was significantly higher with the addition of a GS stain. A map-like GS staining pattern was highly specific (99.3%) for FNH. However, GS staining was interpreted as non-map-like in 14.4% of reviews of true FNH cases, and overall interobserver agreement for interpretation of the GS staining pattern was only moderate (kappa = 0.42). CONCLUSIONS: Pathologists are reasonably accurate in the diagnosis of FNH on virtual biopsies, and GS staining improves accuracy. However, a subset of FNH cases remain challenging. Steatosis and a pseudo-map-like GS staining pattern were associated with increased difficulty. Therefore, although a map-like GS staining pattern is useful for confirmation of a diagnosis, the lack of a map-like GS staining pattern on needle biopsy does not necessarily exclude a diagnosis of FNH.

The diagnosis of clinically significant oesophageal Candida infections: a reappraisal of clinicopathological findings.

AIMS: Distinguishing true oesophageal Candida infections from oral contaminants is a common diagnostic issue. Historically, histological features believed to indicate true infection included epithelial invasion by pseudohyphae and intraepithelial neutrophils. Whether or not these features correlate with endoscopic lesions, symptoms and response to therapy has never been tested in a large cohort. The aim of this study was to determine whether specific histological features correlate with clinical and endoscopic findings when Candida is found in oesophageal biopsies. METHODS AND RESULTS: We reviewed 271 biopsies in which Candida was detected. Cases were evaluated for the presence of desquamated epithelial cells, location/type of fungal forms, neutrophils, and ulceration. Medical records were reviewed for clinical history, endoscopic lesions, and response to antifungal therapy. Statistical analysis was used to determine whether any histological features significantly correlated with clinical variables. There were 120 males and 151 females with a mean age of 42 years. Fifty-nine per cent had symptoms referable to the oesophagus, particularly dysphagia (36%). Most (73%) patients had abnormal endoscopic findings, with plaques, ulcers, or macroscopic evidence of oesophagitis. Seventy-one per cent of patients with documented antifungal therapy showed symptomatic improvement. Overall, there was no statistically significant correlation between any histological feature and presenting symptoms, endoscopic findings, or response to therapy. Importantly, the lack of pseudohyphae, demonstrable invasion of intact epithelium or neutrophilic infiltrates did not exclude clinically significant infection. CONCLUSIONS: We conclude that detection of Candida in oesophageal biopsies is always potentially clinically significant. Treatment decisions should be made on the basis of an integration of clinical, endoscopic and histological findings.

[Intracardial fungal multiplication of order Mucor in an almost totally carbonised part of a male body found after ten days missing]. / Intrakardiálne pomnozenie plesní rodu Mucor v takmer totálne uhorenom torze tela muza po 10 dnoch od jeho zmiznutia.

Determination of time of death belongs to the most difficult and also the most important issues for the medical examiners, especially those who deal with violent death. Besides the most frequently evaluated postmortal changes it is sometimes possible to perform the evaluation on the basis of less frequently observed findings. One of such findings is for example the fungal multiplication on the body or in the very close vicinity. Knowledge of moulds as well as information about their speed of growth should contribute to confirmation or negation of some information gained during police investigation. In this case report authors describe the macroscopically visible fungal intracardiac multiplication in heart chambers and aorta in an almost totally carbonised body which was missing for only ten days. Based on the molecular examination it was detected that the body belonged to the 64-year-old man who was repeatedly hospitalised in psychiatry for depression with suicidal tendencies. The last hospitalisation was six weeks before death and there was no organic disability. The cause of fire was a naked flame. The cause of death was burn injury or asphyxia. The almost total carbonisation did not allow to perform toxicological investigation. By histological investigation we found the presence of wide long non-septate moulds growing in the heart muscle, which belonged to the order Mucor. Since there was no obvious inflammatory response, we suppose their growth started on the congealed blood after death.

Update on infectious enterocolitides and the diseases that they mimic.

The anatomic pathologist's ability to diagnose infections, including gastrointestinal infections, in tissue sections has improved greatly in recent years. With the increasing number and availability of new molecular assays and immunostains, pathologists' understanding of the correlation between histologic patterns of inflammation and specific organisms or groups of organisms has expanded, as well as our understanding of how closely infections can mimic other frequently encountered diseases in gastrointestinal pathology (such as chronic idiopathic inflammatory bowel disease and ischemia). Anatomic pathologists continue to play a critical role in the diagnosis of gastrointestinal infections, as the examination of slides may provide a much more rapid result than microbiological cultures or other laboratory assays, and often cultures are not obtained before the patient is treated with antibiotics. Because many gastrointestinal infections are acquired through contaminated water and food, this review will focus primarily on food and water-borne infectious enterocolitides.

Fungal infections of the gastrointestinal tract in the immunocompromised host: an update.

Fungal infections are one of the most significant causes of morbidity and mortality in immunocompromised patients. The incidence of invasive fungal infections, including those of the gastrointestinal tract, has increased significantly as numbers of immunocompromised patients have increased. The diagnosis of fungal infections in immunocompromised patients may be particularly problematic as these patients may present with atypical clinical features. Although Candida and Aspergillus species represent the majority of fungi diagnosed in the immunocompromised patient population, other fungi are emerging as increasingly common pathogens, and this review will focus on several important emerging fungal infections in immunocompromised patients.

Enterocolitis in immunocompromised patients.

Diarrhea is a very common complaint among immunocompromised patients, and the most common causes of this and other gastrointestinal complaints in this population differ from those commonly seen in immunocompetent patients. Underlying immunodeficiencies may be associated with particular patterns of gastrointestinal tract injury, and particular immunodeficiencies may lead to increased susceptibility to infection by specific organisms depending upon the etiology of the immune compromise. It is important to become familiar with the causes of gastrointestinal disease in the immunocompromised patient population because prompt and proper treatment is of the essence in this patient group. This review focuses on common causes of enterocolitis in the immunocompromised with attention to primary immunodeficiency disorders, the post-transplant setting, chemotherapy-related injury, and a select group of common or emerging infections.

Nonspecificity of Immunohistochemistry for Mycobacteria Species Using a Rabbit Polyclonal Antibody.

CONTEXT.­: Recent publications have featured immunohistochemistry (IHC) as a sensitive tool for detecting Mycobacterium tuberculosis and nontuberculous mycobacteria, but performance is limited to cases suspected to have mycobacterial infection. OBJECTIVE.­: To examine cross-reactivity of a polyclonal antimycobacterial antibody with various types of pathogens, tissues, and inflammatory patterns. DESIGN.­: Surgical pathology files during a period of 6 years were searched, and 40 cases representing a variety of pathogens, tissue types, and inflammatory responses were retrieved. Cases were stained with a rabbit polyclonal antimycobacterial antibody (Biocare Medical, Pacheco, California). The cases and associated histochemical stains, culture, and molecular results were reviewed by 3 pathologists. RESULTS.­: All 8 cases of mycobacterial infection previously diagnosed by other methods were positive for mycobacteria by IHC. In addition, multiple bacterial and fungal organisms and 1 case of Leishmania amastigotes were also immunoreactive with the mycobacterial IHC. CONCLUSIONS.­: Although highly sensitive for mycobacteria, the polyclonal antibody shows significant cross-reactivity with other organisms. This is a sensitive but nonspecific stain that can be used as an alternative confirmation method for mycobacteria, but attention should be paid to inflammatory reaction and organism morphology when IHC is positive to avoid misdiagnosis.

Histologic Features of Mycobacterial Spindle Cell Pseudotumors: A Multi-institutional Clinicopathologic Analysis of 14 Cases.

Mycobacterial spindle cell pseudotumors (MSPs) are a rare and diagnostically challenging manifestation of non-tuberculous mycobacterial (NTM) infections. Proper recognition of these pseudotumors is important because they are treatable and benign. In this study, we evaluated the morphologic patterns of MSPs to improve their pathologic identification. Clinical and morphologic features of 14 MSPs were analyzed. Histologic factors evaluated included the architectural growth pattern of spindled or epithelioid macrophages, granulomas and their location within the lesion, neutrophilic microabscesses, multinucleated giant cells, necrosis, and effacement of background tissue. The composition of inflammatory infiltrates, organism density by acid-fast staining, and stromal changes were also assessed. In addition, 8 of 14 cases underwent molecular microbiology identification by a clinical amplicon-sequencing assay for non-tuberculous mycobacteria. MSP sites included 2 bowel, 10 lymph nodes, 1 liver, and 1 extremity. Cases with available clinical history (n=10) all occurred in immunocompromised patients. All demonstrated effacement of normal structures with spindled cells arranged in a storiform or fascicular architectural pattern. In addition, all cases showed lymphocytic inflammation, with prominent concurrent neutrophilic inflammation in 50% (7/14) of cases. Other morphologic findings included foamy histiocytes (64%, 9/14), peripherally situated granulomas (21%, 3/14), and neutrophilic microabscesses (21%, 3/14). All tested cases were positive for NTM by PCR methods. Mycobacterium avium was the most commonly isolated pathogen (6/8). Mycobacterial spindle cell pseudotumors show predominantly spindled morphology that may be mistaken as a neoplasm. Surgical pathologists who evaluate lymph nodes, soft tissue, and gastrointestinal tissues should be aware of this spindled tumefactive phenomenon in the setting of immunocompromised patients. Recognition of key morphologic features of neutrophilic inflammation, peripheral granulomas, or foamy histiocytes within a spindled lesion can help guide the pathologist to a correct diagnosis of an inflammatory process secondary to infection rather than a spindle cell neoplasm. Accurate diagnosis to facilitate appropriate antimicrobial and/or surgical therapy requires a comprehensive evaluation combining clinical, histopathologic, and microbiological findings.

Pathogenic Yersinia DNA in intestinal specimens of pediatric patients with Crohn's disease.

Studies indicate a close relationship between Yersinia and Crohn's disease in adults. Our study tested 77 colonic specimens from children with Crohn's disease for the presence of Yersinia DNA using a validated polymerase chain reaction (PCR) assay. Control cases included specimens from 45 ulcerative colitis patients and 10 appendicitis patients. The presence of Yersinia in Crohn's specimens was significant compared to the control specimens (9% vs. 0%; p = 0.0055). While our study supports the medical literature, future studies are needed to determine if the relationship between Crohn's disease and Yersinia is an initiating or mediating factor in the pathogenesis of pediatric Crohn's disease.

Infectious Disease Pathology of the Gastrointestinal Tract: Diagnosing the Challenging Cases.

Infectious diseases of the GI tract mimic a variety of other GI diseases, including chronic idiopathic inflammatory bowel disease and ischemia. It can be challenging to identify pathogens in tissue sections as well, as many trainees are not exposed to infectious disease pathology other than in the context of microbiology. Our ability to diagnose infections in formalin fixed, paraffin embedded material has grown exponentially with the advent of new histochemical and immunohistochemical stains, as well as more options for molecular testing. Correlating these diagnostic techniques with morphology has led to increasing understanding of the histologic patterns that are associated with specific pathogens.

Histologic Features of Syphilitic Gastritis: A Rare but Resurging Imitator of Common Diseases.

OBJECTIVES: The range of histopathologic features of gastric syphilis is not well described. Here we describe the clinicopathologic findings of eight patients with syphilitic gastritis. METHODS: A search of our Pathology Data System (2003-2022) and multiple other institutions identified eight patients with syphilitic gastritis. Clinical information, pathology reports, and available slides were reviewed. RESULTS: Lesions predominated in middle-aged adults (mean age, 47.2 years; range, 23-61 years) with a propensity for men (n = 7). Three patients had a documented history of human immunodeficiency virus. Clinical presentations included weight loss, abdominal pain, hematochezia, fever, dyspepsia, nausea and vomiting, hematemesis, anemia, and early satiety. Endoscopic findings included ulcerations, erosions, abnormal mucosa, and nodularity. All specimens shared an active chronic gastritis pattern with intense lymphohistiocytic infiltrates, variable plasma cells, and gland loss. Prominent lymphoid aggregates were seen in four specimens. The diagnosis was confirmed either by immunostain for Treponema pallidum (n = 7) or by direct immunofluorescence staining and real-time polymerase chain reaction (n = 1). All patients with available follow-up data showed resolution of symptoms after antibiotic therapy (n = 4). CONCLUSIONS: Recognition of the histologic pattern of syphilitic gastritis facilitates timely treatment, prevents further transmission, and avoids unnecessarily aggressive treatment.

Pronounced squamous cell contamination in biliary tract cytology: A diagnostic pitfall.

Squamous cells are rarely found in biliary tract cytology specimens, and when present are typically scant in quantity. Over an 8-year time period, two cases at our institution reporting abundant squamous cells were identified. Both patients underwent endoscopic retrograde cholangiopancreatography with bile duct brushings and removal of a migrated biliary stent. The migrated stents were retrieved using rat toothed forceps and required removal of the endoscope through the esophagus with the stent exposed to esophageal and oral mucosa outside of the endoscope. Cytologic examination of the accompanying biliary stent material accordingly revealed abundant benign squamous cells. However, bile duct brushings showed benign ductal epithelial cells without squamous cells. Prior and subsequent cytology and bile duct surgical pathology specimens did not show squamous metaplasia. Migrated biliary stents that require endoscopic withdrawal increase the risk of contaminating samples with squamous cells. Recognition of this unique scenario is important, as the differential diagnosis includes squamous metaplasia and squamous neoplasia.

Intramural Ova of Enterobius vermicularis in the Appendix-An Egg-Topic Location!

We report an unusual case of appendicitis in a 9-year-old girl in whom the wall of the appendix contained necrotizing granulomas, as well as eggs of Enterobius vermicularis. Although luminal E vermicularis adult parasites are commonly identified in the appendix and luminal eggs are occasionally seen, intramural worms and eggs are rare. We are unaware of earlier reports of ectopic intramural eggs in the appendix. It is important to and make a correct diagnosis, as both, the patient, as well as the family should be treated for enterobiasis.

Histologic and Clinical Correlates of Multiplex Stool Polymerase Chain Reaction Assay Results.

CONTEXT.­: Multiplex stool polymerase chain reaction tests (SPTs) simultaneously test for many enteric pathogens. However, the clinical significance of a positive result, particularly in the context of chronic gastrointestinal disease, remains controversial. OBJECTIVE.­: To determine whether SPT results correlate with findings on colon biopsies obtained within a week of SPT or with clinical features. DESIGN.­: We reviewed 261 colon biopsies during a 15-month period that were obtained within a week of SPT, along with available clinical information, from patients with and without chronic idiopathic inflammatory bowel disease (CIIBD). Statistical analysis was used to test associations between SPT result, histologic features, and clinical variables. RESULTS.­: The most commonly detected pathogens were Clostridium difficile, enteropathogenic Escherichia coli, and norovirus. The presence of underlying CIIBD did not correlate with a positive SPT result or with a specific pathogen. Positive SPT result was significantly associated with neutrophilic activity, pseudomembranes, and increased intraepithelial lymphocytes. In addition, the presence of C difficile on SPT was significantly associated with pseudomembranes and neutrophilic activity. There were no other statistically significant relationships between SPT result and any other histologic abnormality. Only about half of SPT positive results were acted on clinically, and most patients with CIIBD were managed as having a presumed IBD flare. CONCLUSIONS.­: SPTs have many advantages; however, interpretation of results, particularly in the background of chronic gastrointestinal disease, remains a challenge. Therapeutic decisions influenced by a positive SPT result should integrate biopsy findings, clinical data, and other laboratory testing to avoid inappropriate treatment.

Towards high reliability in national pathology education: Evaluating the United States and Canadian Academy of Pathology educational product.

The United States and Canadian Academy of Pathology (USCAP) leadership undertook a high level, global review of educational product outcomes data using high reliability organization (HRO) principles: preoccupation with failure; reluctance to simplify; sensitivity to operations; commitment to resilience; and deference to expertise. HRO principles have long been applied to fields such as aviation, nuclear power, and more recently to healthcare, yet they are rarely applied to the field that underpins these-and many other-complex systems: education. While errors in education are less calamitous than in air travel or healthcare delivery, USCAP's educational products impact over 15,000 learners a year, and thus have important implications for the future practice of pathology. Here we report USCAP's experiences using HRO principles to evaluate our keystone educational product, the "USCAP Short Course." Following this novel method of data review, USCAP leadership was able to better understand diverse learner needs based on practice venue, training level, and course topic. Unexpected lessons included the identification of specifically challenging educational topics, such as molecular pathology, and a need to focus more resources on emerging fields such as quality and patient safety. The results allow USCAP to assess educational product performance using HRO tools, and provide strong data-driven decision support for future national pathology education strategy.

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.