The 1000 Mitoses Project: A Consensus-Based International Collaborative Study on Mitotic Figures Classification.

Introduction. The identification of mitotic figures is essential for the diagnosis, grading, and classification of various different tumors. Despite its importance, there is a paucity of literature reporting the consistency in interpreting mitotic figures among pathologists. This study leverages publicly accessible datasets and social media to recruit an international group of pathologists to score an image database of more than 1000 mitotic figures collectively. Materials and Methods. Pathologists were instructed to randomly select a digital slide from The Cancer Genome Atlas (TCGA) datasets and annotate 10-20 mitotic figures within a 2 mm2 area. The first 1010 submitted mitotic figures were used to create an image dataset, with each figure transformed into an individual tile at 40x magnification. The dataset was redistributed to all pathologists to review and determine whether each tile constituted a mitotic figure. Results. Overall pathologists had a median agreement rate of 80.2% (range 42.0%-95.7%). Individual mitotic figure tiles had a median agreement rate of 87.1% and a fair inter-rater agreement across all tiles (kappa = 0.284). Mitotic figures in prometaphase had lower percentage agreement rates compared to other phases of mitosis. Conclusion. This dataset stands as the largest international consensus study for mitotic figures to date and can be utilized as a training set for future studies. The agreement range reflects a spectrum of criteria that pathologists use to decide what constitutes a mitotic figure, which may have potential implications in tumor diagnostics and clinical management.

Hepatic graft-versus-host disease: what we know, when to biopsy, and how to diagnose.

Graft-versus-host disease (GVHD) is one of the serious complications that may develop after hematopoietic cell transplantation (HCT), for hematologic malignancies, solid organ transplantation, and other hematologic disorders. GVHD develops due to T lymphocytes present in the graft attacking the host antigens, which results in tissue damage. A significant number of HCT patients develop acute or chronic GVHD, which may affect multiple organs including the liver. The diagnosis of hepatic GVHD (hGVHD) is challenging as many other conditions in HCT patients may lead to liver dysfunction. Particularly challenging among the various conditions that give rise to liver dysfunction is differentiating sinusoidal obstruction syndrome and drug-induced liver injury (DILI) from hGVHD on clinical grounds and laboratory tests. Despite the minimal risks involved in performing a liver biopsy, the information gleaned from the histopathologic changes may help in the management of these very complex patients. There is a spectrum of histologic features found in hGVHD, and most involve histopathologic changes affecting the interlobular bile ducts. These include nuclear and cytoplasmic abnormalities including dysmorphic bile ducts, apoptosis, and cholangiocyte necrosis, among others. The hepatitic form of hGVHD typically shows severe acute hepatitis. With chronic hGVHD, there is progressive bile duct loss and eventually fibrosis. Accurate diagnosis of hGVHD is paramount so that timely treatment and management can be initiated. Techniques to prevent and lower the risk of GVHD from developing have recently evolved. If a diagnosis of acute GVHD is made, the first-line of treatment is steroids. Recurrence is common and steroid resistance or dependency is not unusual in this setting. Second-line therapies differ among institutions and have not been uniformly established. The development of GVHD, particularly hGVHD, is associated with increased morbidity and mortality.

Hepatocellular carcinoma in patients cured of chronic hepatitis C: Minimal steatosis.

BACKGROUND: Successful treatment of hepatitis C reduces liver inflammation and fibrosis; however, patients remain at risk of developing hepatocellular carcinoma (HCC). AIMS: To identify risk factors for new-onset HCC in patients cured of hepatitis C. METHODS: Imaging, histological, and clinical data on patients whose first HCC was diagnosed >12 months of post-SVR were analyzed. Histology of 20 nontumor tissues was analyzed in a blinded manner using the Knodel/Ishak/HAI system for necroinflammation and fibrosis/cirrhosis stage and the Brunt system for steatosis/steatohepatitis. Factors associated with post-SVR HCC were identified by comparison with HALT-C participants who did not develop post-SVR HCC. RESULTS: Hepatocellular carcinoma was diagnosed in 54 patients (45 M/9F), a median of 6 years of post-SVR [interquartile range (IQR) =1.4-10y] at a median age of 61 years (IQR, 59-67). Approximately one-third lacked cirrhosis, and only 11% had steatosis on imaging. The majority (60%) had no steatosis/steatohepatitis in histopathology. The median HAI score was 3 (1.25-4), indicating mild necroinflammation. In a multivariable logistic regression model, post-SVR HCC was positively associated with non-Caucasian race (p = 0.03), smoking (p = 0.03), age > 60 years at HCC diagnosis (p = 0.03), albumin<3.5 g/dL (p = 0.02), AST/ALT>1 (p = 0.05), and platelets <100 × 103 cells/µL (p < 0.001). Alpha fetoprotein ≥4.75 ng/mL had 90% specificity and 71% sensitivity for HCC occurrence. Noncirrhotic patients had larger tumors (p = 0.002) and a higher prevalence of vascular invasion (p = 0.016) than cirrhotic patients. CONCLUSIONS: One-third of patients with post-SVR HCC did not have liver cirrhosis; most had no steatosis/steatohepatitis. Hepatocellular carcinomas were more advanced in noncirrhotic patients. Results support AFP as a promising marker of post-SVR HCC risk.

Liver Transplantation for Extra-Hepatic Manifestation of Hereditary Hemorrhagic Telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disorder distinguished by multiple arteriovenous malformations that can affect the liver and lungs, and additionally cause high-output heart failure. Effective medical treatment for HHT-related heart failure is limited. While most types of heart failure are contraindications in liver transplants, HHT-related high-output heart failure is an indication for a liver transplant. However, this is rarely performed as it poses a higher-than-average intraoperative risk. We present a case of a 57-year-old female patient with HHT and high-output heart failure from HHT who underwent a successful orthotopic liver transplant to significantly improve her heart function. Incidentally, the patient had a concomitant diagnosis of primary biliary cholangitis (PBC) from her explanted liver. We review the literature on liver transplants related to HHT and perioperative risks associated with heart failure and pulmonary hypertension that may be associated with both HHT and PBC.

PAXgene Fixation for Pancreatic Cancer: Implications for Molecular and Surgical Pathology.

Genomic profiling of pancreatic cancer using small core biopsies has taken an increasingly prominent role in precision medicine. However, if not appropriately preserved, nucleic acids (NA) from pancreatic tissues are known to be susceptible to degradation due to high intrinsic levels of nucleases. PAXgene fixation (PreAnalytix, Switzerland) represents a novel formalin-free tissue preservation method. We sought to compare the NA and histomorphological preservation of pancreatic cancer tissues preserved with PAXgene-fixed paraffin-embedding (PFPE) and formalin-fixed paraffin-embedding (FFPE). Tissues from 19 patients were obtained prospectively from pancreaticoduodenectomy specimens and evaluated by four gastrointestinal pathologists. The extracted NA were quantified by Nanodrop and Qubit and assessed for quality by qPCR, targeted next-generation sequencing (NGS) assay, and RNA-sequencing. Our results demonstrated that, when assessed blindly for morphological quality, the four pathologists deemed the PFPE slides adequate for diagnostic purposes. PFPE tissues enable greater yields of less fragmented and more amplifiable DNA. PFPE tissues demonstrated significantly improved quality control (QC) metrics in a targeted NGS assay including Median Absolute Pair-wise Difference (MAPD) scores. Our results support the use of PAXgene fixative for the processing of specimens from pancreatic cancers with the potential benefits of improved yields for more amplifiable DNA in low-yield biopsy specimens and its ideal use for amplicon-based NGS assays.

Hepatic Secondary Syphilis Can Cause a Variety of Histologic Patterns and May Be Negative for Treponeme Immunohistochemistry.

The rate of syphilis in the United States has been increasing steadily in the past decade, but it remains an uncommon diagnosis in tissue biopsies. Most of the pathology literature on hepatic syphilis consists of older series or case reports. This study aimed to systematically characterize the histologic spectrum of hepatic syphilis in a contemporary cohort. Clinicopathologic features of 14 hepatic syphilis cases between 2012 and 2018 were analyzed to characterize the broad spectrum of histologic changes. Thirteen patients were men (age range: 19 to 59 y); 6 had known human immunodeficiency virus, 7 were men known to have sex with men, and no patient had known prior syphilis. Hepatic syphilis was the primary clinical suspicion in only 1 patient. Common symptoms included jaundice, rash, and abdominal pain. Thirteen had elevated transaminases, and 12 had elevated alkaline phosphatase. Pathologic changes were grouped into 5 histologic patterns: biliary-pattern injury (n=5), acute hepatitis (n=4), autoimmune hepatitis-like (n=1), fibroinflammatory mass-forming lesion (n=2), and no particular pattern (n=2). Nearly all showed portal and lobular lymphocytes and plasma cells; 12 had prominent histiocytes/Kupffer cells, 9 had ductular reaction, and 7 had duct inflammation. Occasional focal findings included dropout (n=7), phlebitis (n=7), and loose granulomata (n=5). Treponeme immunohistochemistry was positive in 10 and negative in 4, though treatment was given before biopsy in 3 of those 4. Thirteen patients had rapid plasma reagin testing either before or after biopsy, with 1:64 or higher titer. All patients who received treatment recovered. Hepatic syphilis is rare but likely underrecognized. It exhibits a variety of histologic appearances and therefore should be considered in several hepatic differential diagnoses, especially in men who have sex with men. Kupffer cells, granulomata, and phlebitis may suggest the diagnosis regardless of predominant histologic pattern. Negative treponeme immunohistochemical staining does not exclude the diagnosis, including in untreated patients.

Benign Neoplasms, Mass-Like Infections, and Pseudotumors That Mimic Hepatic Malignancy at MRI.

A variety of conditions may mimic hepatic malignancy at MRI. These include benign hepatic tumors and tumor-like entities such as focal nodular hyperplasia-like lesions, hepatocellular adenoma, hepatic infections, inflammatory pseudotumor, vascular entities, and in the cirrhotic liver, confluent fibrosis, and hypertrophic pseudomass. These conditions demonstrate MRI features that overlap with hepatic malignancy, and can be challenging for radiologists to diagnose accurately. In this review we discuss the MRI manifestations of various conditions that mimic hepatic malignancy, and highlight features that may allow distinction from malignancy. Level of Evidence 5 Technical Efficacy Stage 3.

Direct-Acting Antiviral Treatment of Patients with Hepatitis C Resolves Serologic and Histopathologic Features of Autoimmune Hepatitis.

Patients with hepatitis C virus (HCV) often have elevated serum markers and histologic features of autoimmune hepatitis (AIH). We evaluated an HCV-positive (HCV+) study group that had elevated serum markers of AIH before starting direct-acting antiviral (DAA) therapy (n = 21) and compared them to an HCV+ control group that did not have laboratory studies suggesting AIH (n = 21). Several patients in the study (17/21) and control (11/21) groups had liver biopsies before DAA treatment, and many were biopsied due to elevated serum markers of AIH. Evaluation of pre-DAA treatment liver biopsies showed histologic features suggestive of AIH in 64.7% (11/17) of the study group and 45.5% (5/11) of the control group. Patients who were HCV+ with elevated serum markers of AIH had significantly increased hepatitis activity (P < 0.001) and slightly increased fibrosis stages (P = 0.039) in their pretreatment liver biopsies compared to controls. We hypothesized that the elevated serum markers and histologic features of AIH would resolve following DAA treatment. Serum markers of AIH in the study group began decreasing by 6 months posttreatment, and 52.4% (11/21) had complete resolution. Alanine aminotransferase levels significantly decreased into the normal range for all patients (21/21). Even patients that had persistence of serum markers of AIH after DAA treatment had normal transaminases. Six patients from the study patient group and 4 patients from the control group had follow-up liver biopsies after DAA treatment, and all biopsies showed resolution of the histologic features of AIH. Conclusion: The majority of HCV+ patients that have serum markers and/or histopathologic features of AIH should initially be treated with DAA.

Development of a novel histologic diagnostic algorithm for hepatic graft-versus-host disease.

The histopathologic diagnosis of hepatic graft-versus-host disease post bone marrow and stem cell transplantation can be challenging, but timely and unambiguous diagnosis is essential for appropriate patient management. To address this diagnostic dilemma, we identified histologic features specific for hepatic graft-versus-host disease and developed a diagnostic algorithm. Two hepatopathologists blindly evaluated 40 liver biopsies from patients with clinically and biologically confirmed graft-versus-host disease, as well as 44 controls, for percent bile duct loss, bile duct damage, intraepithelial lymphocytes, ductular reaction, acidophilic bodies/10 high power fields (HPF), cholestasis, portal and lobular inflammation, and endotheliitis. Compared with controls, graft-versus-host disease cases had significantly more bile duct loss (P<0.0001), bile duct damage (P=0.0002), cholestasis (P<0.0001), and acidophilic bodies/10 HPF (P=0.0006), as well as significantly less ductular reaction (P<0.0001). Significance was maintained with a drug-induced liver injury-only control group. No histologic differences were noted in acute versus chronic graft-versus-host disease, nor cholestatic versus hepatitic types. An algorithm to predict likelihood of graft-versus-host disease was developed, with a three-tiered scoring system: 1-2 not, 3-4 probable, and 5-8 unequivocal graft-versus-host disease. This algorithm had a sensitivity of 93%, specificity of 93%, and accuracy of 92%. We identified histologic features with specificity for hepatic graft-versus-host disease and developed a simple algorithm for pathologists to predict its likelihood, distinguishing this critical diagnosis promptly from mimickers having vastly different treatments and prognoses.

Spermatocytic Tumor With Sarcoma: A Rare Testicular Neoplasm.

Spermatocytic tumor, formerly known as spermatocytic seminoma, is an uncommon testicular neoplasm which is a distinct clinicopathologic entity from classic seminoma. These tumors are not associated with germ cell neoplasia in situ, other germ cell tumors, or isochromosome 12p. Although typically, these tumors have an excellent prognosis occasional cases are associated with sarcoma and have a very poor prognosis. We present a case of spermatocytic tumor with sarcoma showing a chondrosarcomatous component, discuss the pathologic findings and differential diagnosis and provide follow-up information.

Multifocal Intrahepatic Artery Aneurysm with FDG-avid Thrombosis Simulating Metastasis: Report of a Rare Case.

Hepatic artery aneurysm (HAA), although rare, represents a serious diagnostic and therapeutic challenge due to high rupture rate and associated mortality. Early detection and accurate diagnosis are essential for successful management. Here, we present an extremely rare case of multi-focal intrahepatic HAA with confined intrahepatic rupture and hypermetabolic activity at PET imaging, simulating metastasis of melanoma. A retrospective review found only two other HAA at our institution between 2000 and 2015, both of which involved the extrahepatic artery. This report highlights the importance of clinical, radiological, and pathological correlation in the management of this rare condition.

An Unusual Cause of Acute Liver Failure: Three Cases of Hemophagocytic Lymphohistiocytosis Presenting at a Transplant Center.

Acquired hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disorder of the immune system. Hemophagocytic lymphohistiocytosis has been associated with infections, autoimmune disorders, and malignancy. This case series describes three patients admitted to an academic liver transplant center from February 2014 to February 2015 with acute liver failure (ALF) who were ultimately diagnosed with HLH. All cases were female patients (44 to 53 years of age) transferred for workup of ALF. All developed fevers and cytopenias and underwent rapid evaluation for liver transplant by a multidisciplinary team. A complete workup for ALF was negative for intrinsic liver disease and none had significant alcohol or toxin exposure. The patients had liver biopsies showing diffuse lobular necroinflammation, of which two had evidence of hemophagocytosis on histopathology. The diagnosis of HLH was made by bone marrow biopsy featuring histiocytes with hemophagocytosis. All cases were treated with chemotherapy, but died during their hospitalization. Hemophagocytic lymphohistiocytosis can present as ALF in adult patients. Given the low success rate of treatment, early diagnosis is critical. Therefore, a high degree of suspicion should be exercised in patients with unexplained ALF.

Hepatocellular Carcinoma Arising in an HNF-1α-Mutated Adenoma in a 23-Year-Old Woman with Maturity-Onset Diabetes of the Young: A Case Report.

Hepatocyte nuclear factor-1α mutated hepatocellular adenomas (H-HCA) are thought to have no to minimal malignant potential. This report describes a 23-year-old woman with maturity-onset diabetes of the young who developed a 12.5-cm hepatic mass with a radiographically and pathologically distinct 3.0-cm region. Histologically and immunohistochemically, the bulk of the mass was an H-HCA with extensive pseudoglandular formation and only focal steatosis. The 3.0-cm nodule showed small cell change, thickened hepatocyte plates, pleomorphic and hyperchromatic nuclei, reticulin loss, and stromal and vascular invasion, diagnostic of hepatocellular carcinoma (HCC). Immunohistochemically, increased expression of glutamine synthetase in tumor cells and CD34 expression in sinusoidal endothelial cells were seen in the HCC component. Nuclear expression of ß-catenin, and exon 3 of CTNNB1 and TERT promoter mutations were absent in this case. Thus, we report a HCC arising in an H-HCA; although cases appear exceedingly rare, they reinforce the potential of H-HCA for malignant transformation.

Hepatocyte buds derived from progenitor cells repopulate regions of parenchymal extinction in human cirrhosis.

UNLABELLED: Repair of cirrhotic livers occurs, in part, by repopulation with hepatocytes through the stem/progenitor pathway. There remain many uncertainties regarding this pathway. Hepatocyte "buds" occurring in broad septa are hypothesized to be the anatomic manifestation of this pathway. Our purpose was to define a morphologic sequence of bud maturation to allow a quantitative measure of the importance of the stem/progenitor pathway in humans. Histologic sections from 37 liver resection specimens were stained with trichrome, epithelial cell adhesion molecule (EpCAM), K19, CD34, glutamine synthetase (GS), and Ki-67. Specimens were stratified by etiology (10 biliary, 22 nonbiliary, five controls) and stage. Buds were defined as clusters of hepatocytes within septa. Five levels of bud maturation (0-4) were defined by the progressive increase in hepatocyte progeny relative to cholangiocytes. Level 0 single-cell buds are K19(+) /GS(+) /EpCAM(+) /Heppar1(-) . In level 1, the progeny are morphologically hepatocytes (K19(-) /GS(+) /EpCAM(+) /Heppar1(+) ). In level 2-4 buds, hepatocytes increase and become progressively GS(-) and EpCAM(-) . Associated endothelium is CD34(+) in level 1-2 buds and becomes CD34(-) near hepatic veins in level 3-4 buds. Progeny of the bud sequence may represent up to 70% of hepatocytes (immaturity index of 70%). In biliary disease, bud number is reduced in association with duct loss and cholestatic destruction of nascent buds. CONCLUSIONS: The stem/progenitor pathway, manifested anatomically by the bud sequence, is a major mechanism for repopulation of cirrhotic livers. The bud sequence reveals some critical features of hepatic morphogenesis, including that 1) the majority of distal cholangiocytes have stem-like properties, and 2) availability of bile ducts and/or venous drainage are limiting factors for regeneration.