WITHDRAWN: Neoadjuvant therapy leads to objective response in intrahepatic cholangiocarcinoma.

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.hpb.2024.04.011. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Neoadjuvant therapy leads to objective response in intrahepatic cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (iCCA) is the second most common hepatic malignancy and has a poor prognosis. Surgical resection is the standard of care for patients with resectable disease, representing 30-40% of cases. Increasingly, neoadjuvant systemic therapy is being utilized in patients due to high-risk anatomic or biologic considerations. However, data on the clinical effect of this approach are limited. We performed a cohort study to evaluate the effect of neoadjuvant therapy in patients with oncologically high-risk iCCA. METHODS: iCCA patients (n = 181) between the years 2014-2020 were reviewed for clinical, histopathologic, treatment, and outcome-related data. Tumor regression grade was scored per CAP criteria for gastrointestinal carcinomas. RESULTS: 47 iCCA patients received neoadjuvant therapy and 72 did not. Neoadjuvant treatment led to objective response and tumor regression by CAP score. After adjustment for age, clinical stage, and tumor size, the outcomes of patients who had neoadjuvant therapy followed by surgery were not significantly different from those patients who had surgery first. DISCUSSION: In conclusion, neoadjuvant therapy in iCCA facilitated surgical care. The progression-free and overall survival for surgical patients with and without neoadjuvant therapy were not significantly different suggesting this approach needs further exploration as an effective treatment paradigm.

Digital Hepatic Iron Content: An Artificial Intelligence Model for Spatially Resolved Histologic Iron Quantitative Analysis in Liver Samples.

Currently, the precise evaluation of tissue hepatic iron content (HIC) requires laboratory testing using tissue-destructive methods based on colorimetry or spectrophotometry. To maximize the use of routine histologic stains in this context, we developed an artificial intelligence (AI) model for the recognition and spatially resolved measurement of iron in liver samples. Our AI model was developed using a cloud-based, supervised deep learning platform (Aiforia Technologies). Using digitized Pearl Prussian blue iron stain whole slide images representing the full spectrum of changes seen in hepatic iron overload, our training set consisted of 59 cases, and our validation set consisted of 19 cases. The study group consisted of 98 liver samples from 5 different laboratories, for which tissue quantitative analysis using inductively coupled plasma mass spectrometry was available, collected between 2012 and 2022. The correlation between the AI model % iron area and HIC was Rs = 0.93 for needle core biopsy samples (n = 73) and Rs = 0.86 for all samples (n = 98). The digital hepatic iron index (HII) was highly correlated with HII > 1 (area under the curve [AUC] = 0.93) and HII > 1.9 (AUC = 0.94). The percentage area of iron within hepatocytes (vs Kupffer cells and portal tract iron) identified patients with any hereditary hemochromatosis-related mutations (either homozygous or heterozygous) (AUC = 0.65, P = .01) with at least similar accuracy than HIC, HII, and any histologic iron score. The correlation between the Deugnier and Turlin score and the AI model % iron area for all patients was Rs = 0.87 for total score, Rs = 0.82 for hepatocyte iron score, and Rs = 0.84 for Kupffer cell iron score. Iron quantitative analysis using our AI model was highly correlated with both detailed histologic scoring systems and tissue quantitative analysis using inductively coupled plasma mass spectrometry and offers advantages (related to the spatial resolution of iron analysis and the nontissue-destructive nature of the test) over standard quantitative methods.

Adding Inflammatory Markers and Refining National Institute on Alcohol Abuse and Alcoholism Criteria Improve Diagnostic Accuracy for Alcohol-associated Hepatitis.

BACKGROUND & AIMS: Although histology is considered the gold standard for diagnosis of alcohol-associated hepatitis (AH), it is not required for entry into therapeutic studies if patients meet National Institute on Alcohol Abuse and Alcoholism (NIAAA) consensus criteria for probable AH. Our aim was to assess the diagnostic accuracy of NIAAA criteria against liver biopsy and to explore new criteria to enhance diagnostic accuracy for AH. METHODS: A total of 268 consecutive patients with alcohol-related liver disease with liver biopsy were prospectively included: 210 and 58 in the derivation and validation cohorts, respectively. NIAAA criteria and histological diagnosis of alcoholic steatohepatitis (ASH) were independently reviewed by clinical investigators and pathologists from Hospital Clínic and Mayo Clinic. Using biopsy-proven ASH as gold standard we determined diagnostic capability of NIAAA criteria and proposed the new improved criteria. RESULTS: In the derivation cohort, diagnostic accuracy of NIAAA for AH was modest (72%) due to low sensitivity (63%). Subjects who did not meet NIAAA with ASH at liver biopsy had lower 1-year survival compared with subjects without ASH (70% vs 90%; P < .001). NIAAAm-CRP criteria, created by adding C-reactive protein and modifying the variables of the original NIAAA, had higher sensitivity (70%), accuracy (78%), and specificity (83%). Accuracy was also higher in a sensitivity analysis in severe AH (74% vs 65%). In the validation cohort, NIAAAm-CRP and NIAAA criteria had a sensitivity of 56% vs 52% and an accuracy of 76% vs 69%, respectively. CONCLUSION: NIAAA criteria are suboptimal for the diagnosis of AH. The proposed NIAAAm-CRP criteria may improve accuracy for noninvasive diagnosis of AH in patients with alcohol-related liver disease.

Performance of an Artificial Intelligence Model for Recognition and Quantitation of Histologic Features of Eosinophilic Esophagitis on Biopsy Samples.

We have developed an artificial intelligence (AI)-based digital pathology model for the evaluation of histologic features related to eosinophilic esophagitis (EoE). In this study, we evaluated the performance of our AI model in a cohort of pediatric and adult patients for histologic features included in the Eosinophilic Esophagitis Histologic Scoring System (EoEHSS). We collected a total of 203 esophageal biopsy samples from patients with mucosal eosinophilia of any degree (91 adult and 112 pediatric patients) and 10 normal controls from a prospectively maintained database. All cases were assessed by a specialized gastrointestinal (GI) pathologist for features in the EoEHSS at the time of original diagnosis and rescored by a central GI pathologist (R.K.M.). We subsequently analyzed whole-slide image digital slides using a supervised AI model operating in a cloud-based, deep learning AI platform (Aiforia Technologies) for peak eosinophil count (PEC) and several histopathologic features in the EoEHSS. The correlation and interobserver agreement between the AI model and pathologists (Pearson correlation coefficient [rs] = 0.89 and intraclass correlation coefficient [ICC] = 0.87 vs original pathologist; rs = 0.91 and ICC = 0.83 vs central pathologist) were similar to the correlation and interobserver agreement between pathologists for PEC (rs = 0.88 and ICC = 0.91) and broadly similar to those for most other histologic features in the EoEHSS. The AI model also accurately identified PEC of >15 eosinophils/high-power field by the original pathologist (area under the curve [AUC] = 0.98) and central pathologist (AUC = 0.98) and had similar AUCs for the presence of EoE-related endoscopic features to pathologists' assessment. Average eosinophils per epithelial unit area had similar performance compared to AI high-power field-based analysis. Our newly developed AI model can accurately identify, quantify, and score several of the main histopathologic features in the EoE spectrum, with agreement regarding EoEHSS scoring which was similar to that seen among GI pathologists.

Artificial intelligence-based reticulin proportionate area - a novel histological outcome predictor in hepatocellular carcinoma.

AIMS: Reticulin stain is used routinely in the histological evaluation of hepatocellular carcinoma (HCC). The goal of this study was to assess whether the histological reticulin proportionate area (RPA) in HCCs predicts tumour-related outcomes. METHODS AND RESULTS: We developed and validated a supervised artificial intelligence (AI) model that utilises a cloud-based, deep-learning AI platform (Aiforia Technologies, Helsinki, Finland) to specifically recognise and quantify the reticulin framework in normal livers and HCCs using routine reticulin staining. We applied this reticulin AI model to a cohort of consecutive HCC cases from patients undergoing curative resection between 2005 and 2015. A total of 101 HCC resections were included (median age = 68 years, 64 males, median follow-up time = 49.9 months). AI model RPA reduction of > 50% (compared to normal liver tissue) was predictive of metastasis [hazard ratio (HR) = 3.76, P = 0.004, disease-free survival (DFS, HR = 2.48, P < 0.001) and overall survival (OS), HR = 2.80, P = 0.001]. In a Cox regression model, which included clinical and pathological variables, RPA decrease was an independent predictor of DFS and OS and the only independent predictor of metastasis. Similar results were found in the moderately differentiated HCC subgroup (WHO grade 2), in which reticulin quantitative analysis was an independent predictor of metastasis, DFS and OS. CONCLUSION: Our data indicate that decreased RPA is a strong predictor of various HCC-related outcomes, including within the moderately differentiated subgroup. Reticulin, therefore, may represent a novel and important prognostic HCC marker, to be further explored and validated.

Metallothionein immunohistochemistry has high sensitivity and specificity for detection of Wilson disease.

Diagnosis of Wilson disease (WD) can be difficult because of its protean clinical presentations, but early diagnosis is important because effective treatment is available and can prevent disease progression. Similarly, diagnosis of WD on liver biopsy specimens is difficult due to the wide range of histologic appearances. A stain that could help identify WD patients would be of great value. The goal of this study was to use mass spectrometry-based proteomics to identify potential proteins that are differentially expressed in WD compared to controls, and could serve as potential immunohistochemical markers for screening. Several proteins were differentially expressed in WD and immunohistochemical stains for two (metallothionein (MT) and cytochrome C oxidase copper chaperone (COX17)) were tested and compared to other methods of diagnosis in WD including copper staining and quantitative copper assays. We found diffuse metallothionein immunoreactivity in all liver specimens from patients with WD (n = 20); the intensity of the staining was moderate to strong. This staining pattern was distinct from that seen in specimens from the control groups (none of which showed strong, diffuse staining), which included diseases that may be in the clinical or histologic differential of WD (steatohepatitis (n = 51), chronic viral hepatitis (n = 40), autoimmune hepatitis (n = 50), chronic biliary tract disease (n = 42), and normal liver (n = 20)). COX17 immunostain showed no significant difference in expression between the WD and control groups. MT had higher sensitivity than rhodanine for diagnosis of WD. While the quantitative liver copper assays also had high sensitivity, they require more tissue, have a higher cost, longer turnaround time, and are less widely available than an immunohistochemical stain. We conclude that MT IHC is a sensitive immunohistochemical stain for the diagnosis of WD that could be widely deployed as a screening tool for liver biopsies in which WD is in the clinical or histologic differential diagnosis.

Outcomes of idiopathic versus secondary nodular regenerative hyperplasia of the liver: A longitudinal study of 167 cases.

BACKGROUND: Nodular regenerative hyperplasia (NRH) is a rare condition characterized clinically by the development of non-cirrhotic portal hypertension. NRH is the histopathological result in the liver of various systemic disease processes including autoimmune disorders, haematological malignancies and medications. However, natural history of this condition has been limited to small case series while patient outcomes pertaining to different aetiologies of NRH are largely unknown. METHODS: A retrospective cohort of consecutive patients diagnosed with pathology-confirmed NRH at Mayo Clinic between 2002 and 2017 was identified. The histological diagnosis of NRH was determined by expert liver pathologists. Patients with metastatic liver disease, history of liver transplantation or younger than 18 were excluded. Potential aetiologies of NRH were classified as haematological, rheumatological, drug-associated, miscellaneous or idiopathic. Long-term mortality was analysed using Kaplan-Meier estimation and Cox regression models. RESULTS: One hundred and sixty-seven consecutive patients with pathology-confirmed NRH were analysed over a 15-year period and followed for a median time of 50 months (1-306 months). The mean age at diagnosis was 53 years. No aetiology or risk factor for NRH was identified in the majority of patients (94, 56.3%), whereas an associated, possibly causal, condition was found in 73 patients (secondary NRH). The most common presenting feature was elevated liver tests (80%), but no significant differences in laboratory tests were seen based on aetiology of NRH. Compared to idiopathic NRH, those with an identified cause had a higher rate of splenomegaly at presentation (54% vs. 27%, p = 0.002). Portal hypertension-related complications at diagnosis were common, with ascites present in one-third of patients. Overall transplant-free survival was 63% at 5 years. Median survival in idiopathic NRH was 9.4 years compared to 7.3 years in secondary NRH. Age, renal function and volume status at presentation were significantly associated with survival; however, MELD score was not. CONCLUSIONS: The rates of liver-related complications and mortality in NRH are low, and only a small number of patients ultimately require liver transplantation. Most patients do not have an identified risk factor or aetiology for NRH, and liver-related outcomes do not appear to differ based on associated, possibly causal, conditions.

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.

A case report of sevelamer-associated recto-sigmoid ulcers.

BACKGROUND: Optimal phosphorous control is an important aspect of the care of patients with end-stage renal disease, and phosphate binders are usually needed. CASE PRESENTATION: A 74-year-old woman with end-stage renal disease on maintenance hemodialysis presented to the emergency room with abdominal discomfort, rectal pain, and blood-tinged stools. Initial concern was for a rectal carcinoma, based on the symptoms and imaging in initial computerized tomography of the abdomen showing rectal wall thickening, and her clinical presentation. She had been treated with the phosphate binder sevelamer for two months. In this case report, we explore the unique features of sevelamer-associated recto-sigmoid ulcers which led to her symptoms. CONCLUSION: Sevelamer is widely used in chronic kidney disease and end-stage renal disease patients with hyperphosphatemia. It is a crosslinked polymeric amine that binds phosphates and bile acids; it is not systemically absorbed. To the authors' knowledge, this is the first reported case of recto-sigmoid ulcers associated with use of this phosphate binder. Nephrologists, pathologists, and gastroenterology sub-specialists should be aware of this recently-reported entity in patients on sevelamer with suggestive symptoms, as this medication is widely used in renal patients.

Bile salt export pump: a sensitive and specific immunohistochemical marker of hepatocellular carcinoma.

AIMS: Bile salt export pump (BSEP) is a transporter expressed exclusively at hepatic canaliculi and drives bile-salt efflux. Minimal data exist about BSEP expression in tumours. We hypothesized that BSEP immunohistochemistry would be specific for hepatocellular carcinoma (HCC). METHODS AND RESULTS: Tissue microarrays, including 48 HCC, 41 cholangiocarcinomas and 24 metastatic tumours in liver, were immunostained for BSEP. Expression was compared with common markers of hepatocytic differentiation including CD10, hepatocyte paraffin-1 antigen (HepPar-1), carcinoembryonic antigen, arginase-1 (ARG) and glypican-3 (GPC-3). BSEP expression was assessed in normal tissues. Special attention was given to adrenal gland (normal and neoplasia). BSEP was easy to interpret and showed no background staining. Canalicular expression was seen in all normal livers, but not in other normal tissue. BSEP was 90% sensitive and 100% specific for HCC (canalicular in 33 of 43 positive cases). The sensitivity of ARG was slightly higher, but specificity was slightly lower (94% for both). HepPar-1 was 90% sensitive and 97% specific. CD10, polyclonal carcinoembryonic antigen (pCEA) and GPC-3 all had lower sensitivity (74, 81 and 54%, respectively). CONCLUSIONS: In malignant tumours in the liver, BSEP marking was 100% specific and 90% sensitive for HCC. The specificity of BSEP for HCC obviates the need to identify a 'canalicular' pattern, which can limit the utility of other canalicular markers.

Esophagitis Dissecans Superficialis: Clinical, Endoscopic, and Histologic Features.

BACKGROUND: Esophagitis dissecans superficialis (EDS) is a desquamative disorder of the esophagus, but there is a paucity of the literature regarding this condition. AIM: We examined our institution's experience to further characterize clinical outcomes, and endoscopic and histopathologic features. METHODS: Endoscopy and pathology databases were retrospectively reviewed from 2000 to 2013 at Mayo Clinic Rochester to identify potential cases of EDS. Medical records and endoscopic images were reviewed to identify cases, and original pathologic specimens were also reviewed. Clinical, endoscopic, and histologic characteristics of EDS were defined. RESULTS: Forty-one subjects were identified with a median age at diagnosis of 65.0 years (IQR 52.8-76.1) and a female preponderance (63.4 %). Many patients were taking a psychoactive agent (73.1 %) or acid-suppressive therapy (58.5 %) preceding the index endoscopy. Strips of sloughed membranes had a predilection for the distal and/or middle esophagus and resolved in 85.7 % of subjects at endoscopic follow-up. Parakeratosis and intraepithelial splitting were histologic features seen in all patients, while splitting of the connective tissue and intraepithelial bullae were seen in 46.2 and 11.1 %, respectively. There were no disease-related complications at a median follow-up of 10.4 months (IQR 1.2-17.2). CONCLUSIONS: EDS is likely under-recognized. A distinct endoscopic feature of EDS is "sloughing" strips of mucosa with parakeratosis and intraepithelial splitting being sine qua non histologic findings. The use of psychoactive agents (particularly a SSRI or SNRI) was prevalent at endoscopic diagnosis, although the clinical relevance of this is uncertain. EDS appears to be a benign, incidental finding without complications.

CT findings in idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) and comparison to other colitides.

PURPOSE: The purpose of this study is to determine computed tomography (CT) findings that aid in differentiating idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) from other colitides. METHODS: Retrospective review of histiologic proven cases of IMHMV (n = 12) with contrast enhanced CT (n = 11) and/or computed tomography angiography (CTA) (n = 9) exams. Control groups comprised of CT of infectious colitis (n = 13), CT of inflammatory bowel disease (IBD) (n = 12), and CTA of other colitides (n = 13). CT exams reviewed by 2 blinded gastrointestinal radiologists for maximum bowel wall thickness, enhancement pattern, decreased bowel wall enhancement, submucosal attenuation value, presence and location of IMV occlusion, peripheral mesenteric venous occlusion, dilated pericolonic veins, subjective IMA dilation, maximum IMA diameter, maximum peripheral IMA branch diameter, ascites, and mesenteric edema. Presence of early filling veins was an additional finding evaluated on CTA exams. RESULTS: Statistically significant CT findings of IMHMV compared to control groups included greater maximum bowel wall thickness, decreased bowel enhancement, IMV occlusion, and peripheral mesenteric venous occlusion (p < 0.05). Dilated pericolonic veins were seen more frequently in IMHMV compared to the infectious colitis group (64% versus 15%, p = 0.02). Additional statistically significant finding on CTA included early filling veins in IMHMV compared to the CTA control group (100% versus 46%, p = 0.008). CONCLUSION: IMHMV is a rare chronic non-thrombotic ischemia predominantly involving the rectosigmoid colon. CT features that may aid in differentiating IMHMV from other causes of left-sided colitis include marked bowel wall thickening with decreased enhancement, IMV and peripheral mesenteric venous occlusion or tapering, and early filling of dilated veins on CTA.

Erythrophagocytosis is not a reproducible finding in liver biopsies, and is not associated with clinical diagnosis of hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease with high mortality. Liver involvement is common (based on elevated liver function tests) with most patients demonstrating acute hepatitis. Liver biopsies are frequently obtained in the setting of suspected HLH for the purpose of identification of erythrophagocytosis, and if present, this finding is thought to suggest or support the diagnosis of HLH. However, there are problems with this approach; in particular, we do not know whether this finding is reproducible or whether it is specific to HLH. Therefore, we conducted a multi-institutional study in which experienced liver pathologists reviewed images taken from liver biopsies from patients with normal liver, acute hepatitis, possible HLH, and clinical HLH to determine if there was agreement about the presence or absence of erythrophagocytosis, and to ascertain whether the finding corresponds to a clinical diagnosis of HLH. Twelve liver pathologists reviewed 141 images in isolation (i.e., no clinical information or diagnosis provided). These came from 32 patients (five normal, 17 acute hepatitis, six HLH, four possible HLH). The pathologists classified each image as negative, equivocal, or positive for erythrophagocytosis. Kappa was .08 (no agreement) for case-level and 0.1 for image-level (1.4% agreement, based on two images which were universally considered negative). There was no difference in the proportion of pathologists who diagnosed erythrophagocytosis among those with different diagnoses at case or image-level (p = 0.82 and p = 0.82, respectively). Thus, erythrophagocytosis is an entirely unreliable histologic parameter in liver, as it is irreproducible and not demonstrably associated with a clinical disease (namely, HLH). Unless and until more reliable guidelines can be established, pathologists should refrain from commenting on the presence or absence of erythrophagocytosis in liver biopsy.

Cholestatic hepatitis C following liver transplantation: an outcome-based histological definition, clinical predictors, and prognosis.

Cholestatic hepatitis C virus (HCV) is a rare form of recurrent HCV following liver transplantation (LT) without specific diagnostic criteria. An outcome-based method to improve its diagnosis and a description of its prognosis are needed. All 1-year post-LT protocol liver biopsy samples and biopsy samples initially reported to show cholestatic HCV from patients transplanted with HCV between February 2002 and December 2009 were reviewed for the inflammation grade, the fibrosis stage, and 4 cholestatic HCV features: ductular proliferation, canalicular cholestasis with or without intracellular cholestasis, hepatocyte swelling with or without lobular disarray, and sinusoidal/pericellular fibrosis. We used patient and graft survival to define histological criteria for cholestatic HCV, and compared the clinical features of these patients to those of patients with minimal or significant post-LT fibrosis. One hundred seventy-nine patients were analyzed, the median age was 56 years, and 73% were male. Patients with 3 or more of the 4 cholestatic HCV criteria had significantly worse survival (log-rank P < 0.001) regardless of the fibrosis stage, and this was used as our novel definition of cholestatic HCV. Using this definition, we found that 27 patients (15%) had cholestatic HCV, 53 (30%) had significant fibrosis (stage ≥ 2/4), and 99 (55%) had minimal fibrosis (stage < 2/4). The final model for clinical predictors of cholestatic HCV included donor age [odds ratio (OR) = 1.37 per decade, P = 0.04] and previous rejection (Banff grade ≥ 5; OR = 4.19, P = 0.002). Total bilirubin was the strongest laboratory predictor of cholestatic HCV (area under the curve = 0.93), whereas the HCV viral load was not a significant predictor. The final model of post-LT survival included the pathology group {cholestatic HCV [hazard ratio (HR) = 6.07, P < 0.001] and significant fibrosis (HR = 2.53, P = 0.02)}, donor age (HR = 1.49 per decade, P < 0.001), and cold ischemia time (HR = 1.11 per hour, P = 0.02). In conclusion, we propose diagnostic criteria for cholestatic HCV that include specific criteria (the presence of at least 3 of the 4 histopathological features on biopsy) and other supportive and exclusionary criteria. Older donor age and rejection increase the risk of cholestatic HCV, and an elevation in the total bilirubin level may help to identify these patients. These criteria must be validated prospectively.

Atypical presentation of a rare disorder; idiopathic myointimal hyperplasia of mesenteric veins (IMHMV): Report of two cases.

INTRODUCTION: Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare type of chronic colonic ischemia. Patients commonly present with progressive abdominal pain, bloody diarrhea, and weight loss. IMHMV is a common mimicker of inflammatory bowel disease. However, medical management does not have a primary role and curative treatment is surgical resection. PRESENTATION OF CASE: We report two cases of IMHMV with atypical presentation. The first is an 82-year-old male who had refractory, painless, explosive, and non-bloody diarrhea initially treated with antidiarrheal medications and dietary changes to no effect. Colonoscopy was not clarifying. However, CT scan had characteristic findings of IMHMV. He underwent partial colectomy and recovered well. The second case is a 59-year-old male who had recurrent episodes of sudden, massive diarrhea. He was initially treated for diverticulitis based on colonoscopy findings but did not experience relief. Eventually, MRI of the abdomen was suggestive of IMHMV. He underwent surgical resection, which confirmed the diagnosis of IMHMV. He was treated for Clostridioides difficile diarrhea five months after surgery and pulmonary embolism seven months after surgery. With over a year of follow up, neither has had disease recurrence. DISCUSSION: Diagnosis and treatment of rare disorders like IMHMV is challenging, especially when they mimic common entities or present in atypical ways. CONCLUSION: We present two cases to highlight IMHMV as part of the differential for colitis-like symptoms. These cases demonstrate the importance of diagnostic imaging in diagnosis. Diagnostic uncertainty can lead to exposure to ineffective medical treatments and delay in curative surgery.

Liver biopsy in modern clinical practice: a pediatric point-of-view.

Liver biopsy remains the foundation of evaluation and management of liver disease in children, although the role of the liver biopsy is changing with development of alternative methods of diagnosis and advancement of hepatic imaging techniques. The indications for liver biopsy are evolving as current knowledge of etiologies, noninvasive biomarker alternatives, and treatment options in pediatric liver disease are expanding. The procedure can often be complicated in children by technical difficulties, cost, and smaller specimen size. Communication and partnership of clinicians with pathologists experienced in pediatric liver diseases are essential. DNA sequencing, novel imaging modalities, noninvasive biomarkers of fibrosis and apoptosis, proteomics, and genome-wide association studies offer potential alternative methods for evaluation of liver disease in children. This review presents specific indications, considerations, methods, complications, contraindications, and alternatives for pediatric liver biopsy.

Transcriptomic Analysis of Cirrhosis-Like Hepatocellular Carcinoma Reveals Distinct Molecular Characteristics and Pathologic Staging Implications.

OBJECTIVES: Cirrhosis-like hepatocellular carcinoma (CL-HCC) is a rare hepatocellular malignancy characterized by multiple tumor nodules that clinically, radiologically, macroscopically, and microscopically mimic cirrhosis. We aimed to elucidate the molecular biology of CL-HCC and determine tumor nodule clonality. METHODS: We performed RNA sequencing on formalin-fixed, paraffin-embedded tissue from confirmed CL-HCC cases (n = 6), along with corresponding nonneoplastic hepatic tissue (n = 4) when available. Transcriptomes from our previous work on steatohepatitic hepatocellular carcinoma and The Cancer Genome Atlas (TCGA) were used for comparison purposes. RESULTS: Histologically, CL-HCC displayed innumerable nodules and extensive vascular invasion. Intratumoral nodule comparison indicated that the multiple nodules were all clonally related, not independent primaries. The unique histomorphologic appearance corresponded with a distinct transcriptome compared with other HCCs, including fibrolamellar HCC (n = 6), steatohepatitic HCC (n = 8), and conventional HCC in TCGA (n = 424). Tumor-normal gene expression analysis revealed consistent overexpression of several genes involved in degradation of tissue matrix. No recurrent translocations or point mutations were identified. CL-HCC showed a gene expression profile indicative of zone 2 hepatocytes. CONCLUSIONS: CL-HCC's distinctive clinicopathologic features correspond to a unique gene expression profile, increased expression of invasive markers, features of zone 2 hepatocytes, and features suggestive of intratumoral nodule monoclonality.

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.

The Voronoi theory of the normal liver lobular architecture and its applicability in hepatic zonation.

The precise characterization of the lobular architecture of the liver has been subject of investigation since the earliest historical publications, but an accurate model to describe the hepatic lobular microanatomy is yet to be proposed. Our aim was to evaluate whether Voronoi diagrams can be used to describe the classic liver lobular architecture. We examined the histology of normal porcine and human livers and analyzed the geometric relationships of various microanatomic structures utilizing digital tools. The Voronoi diagram model described the organization of the hepatic classic lobules with overall accuracy nearly 90% based on known histologic landmarks. We have also designed a Voronoi-based algorithm of hepatic zonation, which also showed an overall zonal accuracy of nearly 90%. Therefore, we have presented evidence that Voronoi diagrams represent the basis of the two-dimensional organization of the normal liver and that this concept may have wide applicability in liver pathology and research.