Novel endoscopic scoring system for immune mediated colitis: a multicenter retrospective study of 674 patients.

BACKGROUND AND AIMS: No endoscopic scoring system has been established for immune-mediated colitis (IMC). This study aimed to establish such a system for IMC and explore its utility in guiding future selective immunosuppressive therapy (SIT) use compared to clinical symptoms. METHODS: This retrospective, international, 14-center study included 674 patients who developed IMC after immunotherapy and underwent endoscopic evaluation. Ten endoscopic features were selected by group consensus and assigned 1 point each to calculate an IMC endoscopic score (IMCES). IMCES cutoffs were chosen to maximize specificity for SIT use. This specificity was compared between IMCESs, and clinical symptoms were graded according to a standardized instrument. RESULTS: A total of 309 (45.8%) patients received SIT. IMCES specificity for SIT use was 82.8% with a cutoff of 4. The inclusion of ulceration as a mandatory criterion resulted in higher specificity (85.0% for a cutoff of 4). In comparison, the specificity of a Mayo endoscopic subscore of 3 was 74.6%, and the specificity of clinical symptom grading was much lower at 27.4% and 12.3%, respectively. Early endoscopy was associated with timely SIT use (P < .001; r = 0.4084). CONCLUSIONS: This is the largest multicenter study to devise an endoscopic scoring system to guide IMC management. An IMCES cutoff of 4 has a higher specificity for SIT use than clinical symptoms, supporting early endoscopic evaluation for IMC.

Measuring depth of invasion of submucosa - invasive adenocarcinoma in oesophageal endoscopic specimens: how good are we?

AIMS: Emerging data support that submucosa-invasive (pT1b) esophageal adenocarcinomas are cured via endoscopic resection, provided that invasion measures ≤500 µm, they lack other histological features predictive of nodal metastasis and have negative margins. Hence, pathologists' measurement of the depth of submucosal invasion in endoscopic resections may dictate further management (i.e. endoscopic follow-up versus oesophagectomy). In this study, we assessed the interobserver agreement in measuring the depth of submucosal invasion in oesophageal endoscopic resections. METHODS AND RESULTS: Six subspecialised gastrointestinal (GI) pathologists from five academic centres independently measured the depth of submucosal invasion in µm from the deepest muscularis mucosae on 37 oesophageal endoscopic resection slides (round 1 scoring). A consensus meeting with a systematic approach for measuring and discussion of pitfalls was undertaken and remeasuring (round 2 scoring) was conducted. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC) and Cohen's kappa statistics. A lack of agreement was seen among the six reviewers with a poor ICC for both rounds: 1 [0.40, 95% confidence interval (CI) = 0.26-0.56] and 2 (0.49, 95% CI = 0.34-0.63). When measurements were categorised as < or >500 µm, the overall agreement among the six reviewers was only fair for both rounds: 1 (kappa = 0.37, 95% CI = 0.22-0.53) and 2 (kappa = 0.29, 95% CI = 0.12-0.46). CONCLUSIONS: Our study shows a lack of agreement among gastrointestinal pathologists in measuring the depth of submucosal invasion in oesophageal endoscopic resections despite formulating a consensus approach for scoring. If important management decisions continue to be based upon this parameter, more reproducible and concrete guidelines are needed.

Selective Immunoreactivity for WT1 Carboxy-Terminus Distinguishes Desmoplastic Small Round Cell Tumor From its Histologic Mimics.

Desmoplastic small round cell tumor (DSRCT) is an aggressive pediatric round cell sarcoma containing a characteristic EWSR1-WT1 gene fusion. In the absence of genetic data, distinguishing DSRCT from other small round cell tumors of childhood can be problematic due to overlapping histologic and immunohistochemical features. We studied the utility of immunohistochemistry with antibodies targeting both the amino-terminal and carboxy-terminal regions of the Wilms tumor-1 (WT1) protein in differentiating these groups of tumors. The study cohort included 33 cases of genetically confirmed pediatric round cell tumors (10 DSRCTs, 12 Wilms tumors, 10 Ewing sarcomas, and 1 CIC-rearranged sarcoma). Immunoreactivities and immunolocalization of both the WT1 amino-terminus and carboxy-terminus were scored and documented. All DSRCTs displayed selective reactivity for only the WT1 carboxy-terminus (10/10), while dual immunoreactivity for both the WT1 carboxy-terminus (12/12) and amino-terminus antibodies (12/12) were characteristic of Wilms tumors. CIC-rearranged sarcoma showed variable WT1 nuclear immunopositivity (1/1, 1/1) and Ewing sarcomas were consistently WT1-negative for both the WT1 amino-terminus (0/10) and carboxy-terminus (0/10). Dual WT1 amino-terminus and carboxy-terminus immunohistochemistry remains a helpful diagnostic tool in discriminating intraabdominal small round cell tumors, which serves as an adjunct to the genetic information in preventing misdiagnosis.

Endoscopic Ultrasound-Guided Confocal Laser Endomicroscopy Increases Accuracy of Differentiation of Pancreatic Cystic Lesions.

BACKGROUND & AIMS: Imaging patterns from endoscopic ultrasound (EUS)-guided needle-based confocal laser endomicroscopy (nCLE) have been associated with specific pancreatic cystic lesions (PCLs). We compared the accuracy of EUS with nCLE in differentiating mucinous from nonmucinous PCLs with that of measurement of carcinoembryonic antigen (CEA) and cytology analysis. METHODS: We performed a prospective study of 144 consecutive patients with a suspected PCL (≥20 mm) who underwent EUS with fine-needle aspiration of pancreatic cysts from June 2015 through December 2018 at a single center; 65 patients underwent surgical resection. Surgical samples were analyzed by histology (reference standard). During EUS, the needle with the miniprobe was placed in the cyst, which was analyzed by nCLE. Fluid was aspirated and analyzed for level of CEA and by cytology. We compared the accuracy of nCLE in differentiating mucinous from nonmucinous lesions with that of measurement of CEA and cytology analysis. RESULTS: The mean size of dominant cysts was 36.4 ± 15.7 mm and the mean duration of nCLE imaging was 7.3 ± 2.8 min. Among the 65 subjects with surgically resected cysts analyzed histologically, 86.1% had at least 1 worrisome feature based on the 2012 Fukuoka criteria. Measurement of CEA and cytology analysis identified mucinous PCLs with 74% sensitivity, 61% specificity, and 71% accuracy. EUS with nCLE identified mucinous PCLs with 98% sensitivity, 94% specificity, and 97% accuracy. nCLE was more accurate in classifying mucinous vs nonmucinous cysts than the standard method (P < .001). The overall incidence of postprocedure acute pancreatitis was 3.5% (5 of 144); all episodes were mild, based on the revised Atlanta criteria. CONCLUSIONS: In a prospective study, we found that analysis of cysts by nCLE identified mucinous cysts with greater accuracy than measurement of CEA and cytology analysis. EUS with nCLE can be used to differentiate mucinous from nonmucinous PCLs. ClincialTrials.gov no: NCT02516488.

Programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) expression in PD-1 inhibitor-associated colitis and its mimics.

AIMS: Immune checkpoint inhibitors (ICIs) have revolutionised the treatment of advanced malignancies by boosting immune-mediated destruction of neoplastic cells, but are associated with side effects stemming from generalised immune system activation against normal tissues. Checkpoint ligand expression in non-tumoral cells of tissues affected by immune-related adverse effects has been described in ICI-associated hypophysitis, myocarditis, and acute interstitial nephritis. We aimed to investigate the tissue expression of the immune checkpoint receptor programmed cell death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), in PD-1 inhibitor-associated colitis (PD1i colitis). METHODS AND RESULTS: PD-1 and PD-L1 immunohistochemical expression levels were analysed in 15 cases of PD1i colitis and potential mimics-infectious colitis and inflammatory bowel disease (IBD). Increased epithelial expression of PD-L1 was observed in PD1i colitis as compared with normal colon and infectious colitis, but the expression level was lower than that in IBD. Conversely, PD-1 expression in inflammatory cells was higher in infectious colitis, intermediate in IBD, and minimal or absent in normal colon and in patients receiving PD-1 inhibitors. CONCLUSIONS: Although our results do not justify the use of PD-L1 as a discriminatory marker of PD1i colitis against other entities within the differential diagnosis, they support the concept that PD1i colitis and IBD have similar pathogenetic mechanisms. They also highlight the fact that PD-L1 epithelial overexpression is a commonly used mechanism of the gastrointestinal tract mucosa to protect itself from inflammatory-mediated damage resulting from different aetiologies, which probably underpins the high incidence of gastrointestinal immune-related adverse effects in patients receiving ICI therapies, in whom this mechanism is disrupted.

EUS-guided confocal laser endomicroscopy: prediction of dysplasia in intraductal papillary mucinous neoplasms (with video).

BACKGROUND AND AIMS: Previous studies have validated EUS-guided needle-based confocal laser endomicroscopy (nCLE) diagnosis of intraductal papillary mucinous neoplasms (IPMNs). We sought to derive EUS-guided nCLE criteria for differentiating IPMNs with high-grade dysplasia/adenocarcinoma (HGD-Ca) from those with low/intermediate-grade dysplasia (LGD). METHODS: We performed a post hoc analysis of consecutive IPMNs with a definitive diagnosis from a prospective study evaluating EUS-guided nCLE in the diagnosis of pancreatic cysts. Three internal endosonographers reviewed all nCLE videos for the patients and identified potential discriminatory EUS-guided nCLE variables to differentiate HGD-Ca from LGD IPMNs (phase 1). Next, an interobserver agreement (IOA) analysis of variables from phase 1 was performed among 6 blinded external nCLE experts (phase 2). Last, 7 blinded nCLE-naïve observers underwent training and quantified variables with the highest IOA from phase 2 using dedicated software (phase 3). RESULTS: Among 26 IPMNs (HGD-Ca in 16), the reference standard was surgical histopathology in 24 and cytology confirmation of metastatic liver lesions in 2 patients. EUS-guided nCLE characteristics of increased papillary epithelial "width" and "darkness" were the most sensitive variables (90%; 95% confidence interval [CI], 84%-94% and 91%; 95% CI, 85%-95%, respectively) and accurate (85%; 95% CI, 78%-90% and 84%; 95% CI, 77%-89%, respectively) with substantial (κ = 0.61; 95% CI, 0.51-0.71) and moderate (κ = 0.55; 95% CI, 0.45-0.65) IOAs for detecting HGD-Ca, respectively (phase 2). Logistic regression models were fit for the outcome of HGD-Ca as predictor variables (phase 3). For papillary width (cut-off ≥50 µm), the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.95, respectively. For papillary darkness (cut-off ≤90 pixel intensity), the sensitivity, specificity, and AUC for detection of HGD-Ca were 87.5% (95% CI, 62%-99%), 100% (95% CI, 69%-100%), and 0.90, respectively. CONCLUSIONS: In this derivation study, quantification of papillary epithelial width and darkness identified HGD-Ca in IPMNs with high accuracy. These quantifiable variables can be used in multicenter studies for risk stratification of IPMNs. (Clinical trial registration number: NCT02516488.).

Knowledge gaps in the appendix: a multi-institutional study from seven academic centers.

Appendix pathology represents uncommonly encountered specimens with unique diagnostic challenges. To delineate common knowledge gaps, extramural consults submitted to seven institutions between 2016-2017 were reviewed. All appendix consults were resections (100%, n = 43), and the majority were directed for consultation by the originating pathologist (95%, n = 41) with no additional studies performed by the consultant (65%, n = 28). This study was dominated by inquiries related to low grade appendiceal mucinous neoplasms (44%, n = 19) and goblet cell carcinoid related neoplasms (19%, n = 8). Of the 43 appendiceal consults, 19 were submitted by the contributing pathologist as low grade appendiceal mucinous neoplasm, but only half of these were diagnosed by the consultant as such (n = 9). Low grade appendiceal mucinous neoplasm-related consultation themes included diverticular disease, criteria for invasion, high grade atypia, extra-appendiceal mucin, and staging. Examples of major disagreements that were downgraded included consults submitted as low grade appendiceal mucinous neoplasm and diagnosed by the consultant as serrated polyp (n = 3), appendicitis (n = 1), and benign appendix (n = 1). Examples of major disagreements-upgraded included cases submitted as low grade appendiceal mucinous neoplasm and diagnosed by the consultant as low grade appendiceal mucinous neoplasm with high-risk features (n = 2) and mucinous adenocarcinoma (n = 2). One case contained both a major disagreement-upgrade (low grade appendiceal mucinous neoplasm changed to high grade appendiceal mucinous neoplasm) and a major disagreement-downgrade (pT3 changed to Tis). Of the 15 cases diagnosed by the consultants as low grade appendiceal mucinous neoplasm, submitted diagnoses included low grade appendiceal mucinous neoplasm (n = 9), adenocarcinoma (n = 5), and one case was submitted without a diagnosis. For goblet cell carcinoid-related consults, the usual inquiry related to distinguishing goblet cell carcinoid from goblet cell carcinoid with adenocarcinoma (adenocarcinoma ex-goblet cell carcinoid). Of the 38 overall consults with a submitted diagnosis, 53% (n = 20) were disagreements, and most of these were major disagreements-downgraded (n = 13).

Two-stain immunohistochemical screening for Lynch syndrome in colorectal cancer may fail to detect mismatch repair deficiency.

Universal screening for Lynch syndrome in colorectal cancer is recommended, and immunohistochemistry for the mismatch repair proteins is commonly used. To reduce cost, some screen using only MSH6 and PMS2, with reflex to the partner stain if either are absent (two-stain method). An expression pattern revealing absent MSH2 and intact MSH6 is not expected, but could result in failed Lynch syndrome detection. We analyzed tumors with absent MSH2 but any degree of MSH6 expression to determine if the two-stain method could miss MSH2 mutations. One-thousand seven-hundred thirty colorectal cancer patients from the Ohio Colorectal Cancer Prevention Initiative underwent tumor screening using microsatellite instability and immunohistochemistry. The two-stain method was used for 1235 cases; staining for all four proteins was completed for 495 cases. The proportion of positive cells and staining intensity were reviewed for MSH6, as well as MSH2 when available. Patients with mismatch repair deficiency underwent next-generation sequencing of germline DNA for mismatch repair genes. If negative, tumor next-generation sequencing was performed to assess for somatic mutations. Overall, thirty-three (1.9%, 33/1730) MSH2-absent cases were identified. Of those, fourteen had no MSH6 expression but eight (0.5%, 8/1730) had ambiguous and eleven (0.6%, 11/1730) had convincing MSH6 expression that could have been interpreted as intact. Germline next-generation sequencing identified MSH2 mutations in 11/14 cases with absence of both stains, 7/8 cases with ambiguous MSH6 expression, and 9/11 cases with convincing MSH6 expression. All remaining cases, except one, had double somatic mutations. The two-stain method fails to detect some patients with Lynch syndrome: (1) significant staining weaker than the control may be incorrectly interpreted as intact MSH6, or (2) Weak or focal/patchy MSH6 can be retained with the absence of MSH2. Accordingly, we recommend the four-stain method be used for optimal Lynch syndrome screening detection.

Some observations on Barrett esophagus and associated dysplasia.

Biopsy samples from esophageal columnar metaplasia and dysplasia are commonly encountered in Western pathology practice and knowing a few pitfalls can save both pathologists and patients a great deal of anxiety. Herein we discuss criteria for Barrett esophagus, evaluation of dysplasia, and some pitfalls in reviewing endoscopic mucosal resections. Also included is a summary of suggested follow-up for patients with Barrett esophagus.

Targeted next-generation sequencing supports epidermoid metaplasia of the esophagus as a precursor to esophageal squamous neoplasia.

Esophageal epidermoid metaplasia is a rare condition that involves the proximal-to-middle third of the esophagus. It is sharply demarcated and defined histologically by epithelial hyperplasia, a prominent granular cell layer, and superficial hyperorthokeratosis. In addition, preliminary studies have suggested an association between esophageal epidermoid metaplasia and esophageal squamous neoplasia (squamous dysplasia and esophageal squamous cell carcinoma). To further characterize esophageal epidermoid metaplasia and better define its relationship to squamous neoplasia of the esophagus, we performed targeted next-generation sequencing on uninvolved esophageal squamous mucosa and matching esophageal epidermoid metaplasia specimens from 18 patients. Further, we evaluated both synchronous and metachronous high-grade squamous dysplasia/esophageal squamous cell carcinoma by next-generation sequencing from 5 of the 18 (28%) patients, and compared these findings to corresponding esophageal epidermoid metaplasia specimens. Targeted next-generation sequencing revealed 12 of 18 (67%) esophageal epidermoid metaplasia specimens' harbored alterations in genes often associated with esophageal squamous cell carcinoma. The most frequently mutated genes consisted of TP53 (n=10), PIK3CA (n=2), EGFR (n=2), MYCN (n=1), HRAS (n=1), and the TERT promoter (n=1). Sequencing of synchronous and metachronous high-grade squamous dysplasia/esophageal squamous cell carcinoma identified shared genetic alterations with corresponding esophageal epidermoid metaplasia specimens that suggests a clonal relationship between these entities. In addition, the presence of a TP53 mutation in esophageal epidermoid metaplasia specimens correlated with concurrent or progression to high-grade squamous dysplasia/esophageal squamous cell carcinoma. No genetic alterations were detected in uninvolved esophageal squamous mucosa. On the basis of these findings, we conclude esophageal epidermoid metaplasia is a precursor to in situ and invasive esophageal squamous neoplasia. Further, the detection of TP53 mutations in esophageal epidermoid metaplasia specimens may serve as an early detection biomarker for high-grade squamous dysplasia/esophageal squamous cell carcinoma.

Massive localized lymphedema: a clinicopathologic study of 46 patients with an enrichment for multiplicity.

Massive localized lymphedema is a monstrous tumefactive pseudosarcoma seen in middle-aged morbidly obese adults. Since its initial description in 1998, the etiology remains unknown, although associations with trauma, surgeries, and hypothyroidism have been reported. Herein, we report the largest study of massive localized lymphedema and expand upon its clinicopathologic features. Fifty-four cases from 46 patients were retrospectively identified from the institutional archives of The Ohio State University Wexner Medical Center between 2002 and 2015. Forty-six patients (21 males and 25 females, mean age 50 years) presented with large masses developing over a 5-60-month period. The majority of patients were Caucasian (n=39). All patients were obese with a mean weight of 384.7 lb and a mean body mass index of 59.6 kg/m(2). Thirty-six patients had a history of atherosclerotic cardiovascular disease and diabetes mellitus type 2 was present in 22 patients. Eight patients had multifocal massive localized lymphedema. The sites included thigh (n=33), abdomen (n=17), suprapubic region (n=1), mons pubis (n=6), scrotum (n=2), perianal region (n=1), and right flank (n=1). Mostly, the clinical impression was benign processes, including pannus or lymphedema pseudotumor. Grossly, the mean weight was 8237 g and the mean size was 53.2 cm. Histologically, eight cases showed a unique pattern of dystrophic calcifications mimicking hyperchromatic, atypical nuclei that might lead to misdiagnosis of liposarcoma, four cases showed focal metaplastic ossification, and three cases showed multinucleated cells in addition to prototypic features of massive localized lymphedema. We report that this is the largest series of massive localized lymphedema. This is a lesion mostly seen in morbidly obese patients and the thigh is the most common site of involvement. We note a marked racial predilection for Caucasians and a tendency towards multiplicity. We suggest that obesity itself and the related metabolic syndrome have an important role in its pathogenesis.

Helicobacter pylori Clarithromycin Resistance and Treatment Failure Are Common in the USA.

BACKGROUND: Helicobacter pylori antibiotic resistance leads to frequent treatment failure. However, the current US prevalence of H. pylori clarithromycin resistance and treatment failure is unknown. AIMS: To determine the prevalence of clarithromycin-resistant H. pylori and its impact on treatment failure in the USA. METHODS: A multicenter, retrospective, cohort study for clarithromycin-resistant H. pylori was conducted over four academic medical centers in different geographic regions of the USA. Gastric biopsy material, residual from standard clinical pathologic examination, was examined for clarithromycin resistance by DNA sequencing of H. pylori 23S rRNA. RESULTS: One hundred and twenty-four cases of H. pylori gastritis were examined from medical centers in four different geographic regions of the USA. The overall prevalence of clarithromycin resistance was 32.3 % (range 23.1-45.8 %). There was no significant difference in the prevalence of clarithromycin resistance by study site, gender, age, or race/ethnicity. In a subset of 67 patients that had clinical follow-up data, the overall prevalence of clarithromycin resistance was 31.3 %. There was a 2.9-fold increase (p = 0.002) in treatment failure for cases with clarithromycin resistance (57.1 %) compared to wildtype H. pylori (19.6 %). CONCLUSIONS: H. pylori clarithromycin resistance in the USA exceeds the estimated 20 % prevalence compatible with successful empiric antibiotic therapy. This resistance resulted in a significant rate of treatment failure in all sites surveyed. Empiric therapy in the USA should be used with caution until there is better regional or local determination of H. pylori antibiotic resistance.

Esophageal leukoplakia or epidermoid metaplasia: a clinicopathological study of 18 patients.

Oral leukoplakia is a relatively common, painless disorder of the oral mucosa. It predominantly affects middle-aged to elderly men and has a strong association with tobacco smoking and alcohol intake. Concomitant histological findings of hyperorthokeratosis and a well-developed granular cell layer, termed orthokeratotic dysplasia, are often associated with oral squamous cell carcinoma. In contrast, analogous lesions within the esophagus, termed esophageal epidermoid metaplasia, are rarely encountered and poorly described in the literature. To better characterize the clinicopathological features of this entity, we have collected 25 cases from 18 patients. Patients ranged in age from 37 to 81 years (mean, 61.5 years), with a slight female predominance (10/18, 56%). On presentation, a majority of patients complained of dysphagia (10/18, 56%). Past medical history was significant for tobacco smoking or long history of second-hand smoke in 11 (61%) patients and alcohol intake in 7 (39%) patients. Seventeen (94%) patients with esophageal epidermoid metaplasia were located within the middle-to-distal esophagus. Histologically, all cases were sharply demarcated and characterized by epithelial hyperplasia, a thickened basal layer, acanthotic midzone, a prominent granular cell layer, and superficial hyperorthokeratosis. Adjacent high-grade squamous dysplasia and/or squamous cell carcinoma were seen in 3 out of 18 (17%) patients. Follow-up information was available for 13 out of 18 (72%) patients and ranged from 2 to 8.3 years (mean, 2.3 years). Seven of the 13 (54%) patients had persistent disease; however, none of them developed squamous dysplasia or squamous cell carcinoma. In an effort to assess the incidence of esophageal epidermoid metaplasia, 198 consecutive esophageal biopsies were prospectively surveyed over a 6-month period at three academic institutions. No cases were identified within this time frame. In summary, esophageal epidermoid metaplasia is a rare condition affecting the middle-to-distal esophagus in middle-aged to elderly females. The occurrence of adjacent high-grade squamous dysplasia and/or squamous cell carcinoma warrants close follow-up.

Sex, lies, and gastrointestinal tract biopsies: a review of selected sexually transmitted proctocolitides.

There are many insults that result in gastrointestinal tract inflammation. Infections can be particularly challenging because (1) only a limited number of organisms provoke a specific endoscopic and/or histologic appearance; and (2) although some organisms may be present on biopsies, the findings may be so subtle or organisms so few that they are easily missed if the reviewer is not performing a specific search for the offender. Sexually transmitted infections (STI) are rarely a consideration at the time of GI biopsy examination and clinicians rarely inquire about sexual behavior at the time of initial patient interview. Although establishing a definitive STI diagnosis is not possible on histology alone, these infections are associated with inflammatory patterns that may help raise this diagnostic possibility. Becoming familiar with these patterns is necessary as worldwide outbreaks of these infections are being reported. This review aims to provide the pathologist with histologic clues associated with the most frequently encountered bacterial pathogens in the setting of STI proctitis, namely, Chlamydia trachomatis, Neisseria gonorrhoeae, and Treponema pallidum.

Detection of cytomegalovirus DNA in plasma as an adjunct diagnostic for gastrointestinal tract disease in kidney and liver transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) disease is the most common infectious complication after solid organ transplantation, frequently affecting the gastrointestinal (GI) tract. There are limited data on quantitative polymerase chain reaction (qPCR) for plasma CMV DNA as an adjunct diagnostic method for GI tract disease in kidney and liver transplant recipients. METHODS: We reviewed all records of adult kidney and liver transplant recipients with a GI tract biopsy and plasma CMV qPCR result within 15 days of biopsy during a 6.5-year period at our center. CMV GI tract disease was defined as histopathologic evidence of CMV on biopsy by immunohistochemistry or visualization of inclusion bodies. RESULTS: GI tract biopsy and qPCR results were available for 81 kidney and liver transplant recipients; 20 cases of confirmed CMV GI tract disease were identified. Overall, the sensitivity of qPCR for diagnosing CMV GI tract disease was 85% (95% confidence interval [CI], 61%-96%), and the specificity was 95% (95% CI, 85%-99%). For CMV-seronegative recipients (R(-)) with CMV-seropositive donors (D(+)), the sensitivity of qPCR was 100% (95% CI, 59%-99%), and the specificity was 80% (95% CI, 30%-99%). The lowest sensitivity was observed in CMV D(+)/R(+) cases (72.7%; 95% CI, 39%-93%). The mean plasma CMV copy number in patients with GI tract disease was 3.84 log10 (38 334 copies/mL). CONCLUSIONS: Plasma CMV qPCR had good sensitivity and excellent specificity for CMV GI tract disease in kidney and liver transplant recipients. Its sensitivity was 100% in CMV D(+)/R(-) cases but 72.7% in CMV D(+)/R(+) cases. This variation in assay performance according to host serostatus may reflect differences in disease pathogenesis.

Drug-induced digestive tract injury: decoding some invisible offenders.

There is an ever-growing list of pharmacological agents, several of which are attributed to cause clinically significant gastrointestinal (GI) injury. Many patients present with significant but nonspecific symptoms, that in conjunction with the absence of relevant drug history on the requisition slip can make the histopathologic diagnosis challenging. To complicate this, although some drugs have relatively characteristic histopathologic features (such as doxycycline), there exist many other drugs that exhibit wide and varying spectra of histopathologic findings (such as immune checkpoint inhibitors or olmesartan) and have histomorphologic overlap with many other commonly encountered disease entities. This review discusses the histopathologic features of some relatively recently described drugs causing GI tract injury, namely doxycycline, tacrolimus, mycophenolate, immune checkpoint inhibitors, and olmesartan. We also discuss the common mimics in histopathologic differential and some pearls that can help distinguish GI tract injury induced by the aforementioned drugs from its mimics. Awareness of the wide spectra of histopathologic changes associated with these drugs is crucial for practicing pathologists, to avoid misdiagnosis and guiding the clinician for an optimal patient management, which usually involves modifying or discontinuing the offending drug. Needless to say, once a diagnosis of drug-induced injury is suspected, clinicopathologic correlation including corroboration with the drug history is of utmost importance as is the exclusion of dual pathology in these patients.

Virtual Pathology Elective, Real Education: The PathElective.com Experience as a Model for Novel Pathology Pedagogy and a Primer for Curricular Evolution.

CONTEXT.­: PathElective.com was created in response to the pandemic's restrictions on interactions with trainees, and since has been incorporated into many training programs worldwide, serving as a unique means of delivering high-quality pathology and laboratory medical education at multiple levels of training. OBJECTIVE.­: To analyze student usage, performance, and satisfaction to provide insight into the effectiveness of virtual education to guide curricular evolution. DESIGN.­: Squarespace (Squarespace, Inc) was used for website development and to collect website analytics. Students were assessed before and after course participation using a dual-form crossover quiz design. Quiz data were anonymous and analyzed with a paired t test to account for varying student background. A novel analysis was performed aimed at examining the attrition rate of students across multiple modules. RESULTS.­: Over the study period (May 1, 2020 to October 31, 2021), PathElective.com received 577 483 page views, 126 180 visits, 59 928 unique visitors, and 10 278 registered users who earned 15 305 certificates. A total of 7338 premodule and postmodule quiz pairs were analyzed. The overall average increase in score was 13.83% (P = .02). All but 5 of the 56 courses experienced a statistically significant increase in score. All courses received median scores of Very Satisfied/Satisfied in all 6 assessment domains. Aggregate attrition data revealed a unique, negative polynomial relationship (R2 = 0.656). CONCLUSIONS.­: PathElective.com is a free, effective means of enhancing anatomic/clinical pathology training in medical education. These analyses offer a unique perspective on the online user experience and could guide the development of future online medical education resources.

Interobserver Variability in Assessment of Depth of Submucosal Invasion for Colonic Endoscopic Resections Among Subspecialized Gastrointestinal Pathologists.

CONTEXT.­: Recent data support that low-risk submucosally invasive (pT1) colonic adenocarcinomas (ie, completely resected tumors that lack high-grade morphology, tumor budding, and lymphovascular invasion) are considered cured via endoscopic resection, provided that the submucosal invasion is less than 1000 µm. Hence, the pathologists' assessment of depth of submucosal invasion may guide further management (ie, surveillance versus colectomy). OBJECTIVE.­: To assess interobserver concordance among gastrointestinal pathologists in measuring submucosal depth of invasion in colonic endoscopic resections. DESIGN.­: Six gastrointestinal pathologists from 5 academic centers independently measured the greatest depth of submucosal invasion in micrometers on 52 hematoxylin-eosin-stained slides from colonic endoscopic specimens with pT1 adenocarcinomas, per published guidelines (round 1 scoring). Two separate measurements (round 2 scoring) were subsequently performed by each pathologist following a consensus meeting, (1) from the surface of the lesion and (2) from the muscularis mucosae, and pathologists were asked to choose their (3) "real-life (best)" assessment between the first 2 measurements. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC) and Cohen κ statistics. RESULTS.­: Round 1 had poor ICC (0.43; 95% CI, 0.31-0.56). Round 2 agreement was good when measuring from the surface (ICC = 0.83; 95% CI, 0.76-0.88) but moderate (ICC = 0.59; 95% CI, 0.47-0.70) when measuring from the muscularis mucosae and became poor (ICC = 0.49; 95% CI, 0.36-0.61) for the best-assessment measurement. CONCLUSIONS.­: Our findings indicate that clearer and reproducible guidelines are needed if clinical colleagues are to base important management decisions on pathologists' estimate of the depth of submucosal invasion in colonic endoscopic resections.