IgG and IgM Immunohistochemistry in Primary Biliary Cholangitis (PBC) and Autoimmune Hepatitis (AIH) Liver Explants.

OBJECTIVES: Primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH) can be difficult to distinguish in end-stage liver disease. Previous studies have shown that immunoglobulin G (IgG) and immunoglobulin M (IgM) immunostaining can differentiate AIH from PBC in needle core biopsy specimens, and we seek to extend these data to cirrhotic liver explants, in which the histology of AIH or PBC may be indiscernible. METHODS: Clinical data were reviewed for 20 patients with PBC cirrhosis and 16 with AIH cirrhosis. Immunohistochemistry for IgM and IgG was performed on representative blocks of explanted livers. Three high-power fields with the highest concentration of IgG- and IgM-positive plasma cells were counted and compared. RESULTS: The average number of IgM-positive plasma cells was significantly higher in PBC explants (7.3) than in AIH (1.8) (P = .001). There was no significant difference in the average number of IgG-positive plasma cells in PBC (2.5) and AIH (2.8) (P = .8). The IgG/IgM ratio was more likely to be less than 1.0 in PBC (17/20, 85%) compared with AIH (7/16, 44%) (P = .01). CONCLUSIONS: Our study demonstrates that the absolute number of IgM plasma cells is greater in explants of cirrhotic PBC compared with AIH. These findings may be helpful in the evaluation of cryptogenic cirrhosis.

Invasive aspergillosis related to ibrutinib therapy for chronic lymphocytic leukemia.

We report a case of invasive pulmonary aspergillosis in a patient taking ibrutinib, a Bruton's tyrosine kinase inhibitor used to treat refractory chronic lymphocytic leukemia. We hypothesize that ibrutinib promoted this infection by suppressing innate immune responses against Aspergillus. Clinicians should be aware of potential Aspergillus infections in patients treated with this drug.

In recurrent primary biliary cirrhosis after liver transplantation, biliary epithelial cells show increased expression of mitochondrial proteins.

In biliary epithelial lesions in primary biliary cirrhosis (PBC), mitochondrial proteins associated with deregulated autophagy are abnormally expressed. We examined whether this could be used as a diagnostic marker for end-stage PBC and recurrent PBC after liver transplantation. We examined the expression of the mitochondrial protein pyruvate dehydrogenase complex-E2 component and cytochrome c oxidase, subunit I (CCO), the autophagy-related marker microtubule-associated protein-light chain 3 (LC3), and p62/sequestosome-1 and the senescence markers p16(Ink4a) and p21(WAF1/Cip1) in small bile ducts and bile ductules in explanted livers from patients with PBC (n = 20) in comparison with liver tissue from control patients (n = 21) and post-transplant samples including recurrent PBC and cellular rejection (n = 28). Intense granular expression of mitochondrial proteins was significantly more frequent in small bile ducts in explanted livers with PBC than in control livers (p < 0.05). Post-transplant samples comprised of three groups: group A (positive for mitochondrial proteins, n = 7), group B (positive for either autophagy-related or senescence markers but negative for mitochondrial proteins, n = 7), and group C (all negative, n = 14). All but one case of group A were clinically and histologically diagnosed as recurrent PBC. In contrast, all cases of group B were diagnosed as cellular rejection. This study suggests that the expression of mitochondrial proteins in small bile ducts may be a useful diagnostic marker for end-stage PBC and recurrent PBC after liver transplantation.

Endometrial cysts within the liver: a rare entity and its differential diagnosis with mucinous cystic neoplasms of the liver.

Endometrial cysts within the liver are rare but can present as diagnostic challenges on small biopsies or frozen sections and may mimic mucinous cystic neoplasms (MCN) of the liver. Five cases of endometrial cysts and 6 cases of MCNs within the liver were collected. The clinicopathological, imaging, and immunohistochemical features were systematically reviewed and compared. The average size of the endometrial cysts was 8.3 cm. Four patients had a prior pelvic operation and coexisting endometriosis at other sites. All 5 cases of endometrial cysts had positive ER staining within both the epithelium and the stroma. PR was also positive in both epithelial and stromal cells in 4 cases. Four cases had additional immunostains performed, which all showed cytokeratin 19 and cytokeratin 7 positivity (only in epithelium) and CD10 positivity (only in stroma). α-Inhibin and calretinin were negative for both the epithelium and the stroma in all 4 cases. All 6 MCN cases (mean size, 11.1 cm) had positive ER, PR, and α-inhibin staining only in the stroma. ER and PR were positive in both the epithelium and stromal cells in endometrial cysts, whereas they were positive only in the stromal cells of MCNs. The stromal cells were CD10 positive and α-inhibin negative in endometrial cysts as opposed to the opposite staining pattern in MCNs. Awareness of this distinct staining pattern and the possibility of endometrial cysts in the liver can lead to accurate diagnoses and appropriate treatment modalities.

Notch1-Hes1 signalling axis in the tumourigenesis of biliary neuroendocrine tumours.

AIMS: Biliary neuroendocrine tumours (NETs) are rare and mostly exist as a component of mixed adenoneuroendocrine carcinomas (MANECs). Although the NET component in biliary MANECs is generally more malignant and clinically more important to the prognosis than the ordinary adenocarcinomatous component, the histogenesis of biliary NET has not been clarified. In this study, the role of the Notch1-Hes1 signalling axis in the histogenesis of biliary NETs was examined. METHODS: Immunohistochemistry for Notch1, its ligand Jagged1 and Hes1 was performed using surgical specimens from 11 patients with biliary MANEC. Moreover, after the knock-down of Notch1 mRNA expression in a cholangiocarcinoma cell line, the expression of chromogranin A (a neuroendocrine marker) and Ascl1 (a neuroendocrine-inducing molecule inhibited by activated Hes1) was examined by quantitative PCR. RESULTS: Histological examination revealed that the adenocarcinomatous components were predominately located at the luminal surface of the MANEC and the majority of stromal invasion involved NET components. Ordinary adenocarcinomas and non-neoplastic biliary epithelium constantly expressed Notch1, Jagged1 and Hes1, but the expression of Notch1 and Hes1 was decreased or absent in NET components, suggesting interference with the Notch1-Hes1 signalling axis in biliary NET. Moreover, in the cholangiocarcinoma cell line in which the expression of Notch1 mRNA was knocked down, the mRNA expression of Ascl1 and chromogranin A was increased. CONCLUSIONS: The Notch1-Hes1 signalling axis suppresses neuroendocrine differentiation and maintains tubular/acinar features in adenocarcinoma and non-neoplastic epithelium in the biliary tree. Moreover, a disruption of this signalling axis may be associated with the tumourigenesis of NETs in biliary MANEC.

KRAS and GNAS mutations and p53 overexpression in biliary intraepithelial neoplasia and intrahepatic cholangiocarcinomas.

BACKGROUND: Similar to the pancreatic intraepithelial neoplasia (PanIN)-pancreatic carcinoma sequence model, intrahepatic cholangiocarcinoma (ICC) also reportedly follows a stepwise carcinogenesis process through the a precursor lesion: biliary intraepithelial neoplasia (BilIN). For this study, the authors investigated the status of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and GNAS complex locus (GNAS) mutations and tumor protein 53 (p53) overexpression in the stepwise process of cholangiocarcinogenesis. METHODS: Thirty patients with hepatolithiasis were surveyed, and their lesions were categorized as follows: non-neoplastic large bile duct (LBD) (n = 12), peribiliary gland (PBG) (n = 9), BilIN-1 (low-grade dysplasia; n = 12), BilIN-2 (high-grade dysplasia; n = 16), and BilIN-3 (noninvasive or in situ carcinoma; n = 10). KRAS mutation at codons 12 and 13 and GNAS mutations at codon 201 were analyzed using genomic DNA extracted from isolated lesions by laser capture microdissection [corrected]. Immunohistochemical expression of p53 also was evaluated in BilIN lesions, ICCs, and extrahepatic cholangiocarcinomas (ExCCs). RESULTS: A prevalence of KRAS mutations was identified in patients with ICC (31.5%), BilIN-3 (30%), and BilIN-2 (43.8%) compared with BilIN-1 (25%). Furthermore, KRAS mutations were detected in LBD lesions (41.7%) and PBG lesions (44.4%), and these mutations were observed with greater frequency in patients who had BilIN with KRAS mutations. GNAS mutations were not identified in any of the ICCs or other lesions examined. The overexpression of p53 was not identified in BilIN lesions and was less frequent in ICCs (18.2%) compared with ExCCs (38.1%) and gallbladder carcinomas (61.5%). CONCLUSIONS: KRAS mutations, which were present in approximately 33% of BilIN lesions, occurred as an early molecular event during the progression of BilIN to ICC, whereas p53 overexpression was identified as a late molecular event. Furthermore, the current results indicted that BilIN also may arise from LBD and PBG lesions in patients who have hepatolithiasis with KRAS mutations.

Application and validation of a new histologic staging and grading system for primary biliary cirrhosis.

BACKGROUND: We proposed a new grading and staging system for primary biliary cirrhosis (PBC), which takes into account the degree of both chronic cholangitis activity (CA) and hepatitic activity (HA) for grading disease activity and that of fibrosis, bile duct loss, and chronic cholestasis for staging. In this study, we validated our new system. METHODS: Using liver biopsy specimens from 166 cases of PBC, chronic cholangitis with mild periductal lymphoplasmacytic infiltration, including chronic nonsuppurative destructive cholangitis, and the combined activity of interface hepatitis and lobular hepatitis were categorized into 4 grades on the basis of their degree and distribution (CA0-3 and HA0-3, respectively). For staging, because orcein staining was not available in this study, 2 criteria (fibrosis and bile duct loss) were independently scored from 0 to 3 on the basis of their degrees, and a final stage score was created from the sum. RESULTS: Although there was a relatively uniform distribution of CA0/1/2/3 cases, the cases of HA0/1/2/3 were distributed as 21%, 64%, 13%, and 3%, respectively, with a prominent number of cases categorized as having none or mild HA. The distribution of stages 1 to 4 using our system was considerably different from that using the classic system and, importantly, showed a correlation with patient outcome. CONCLUSIONS: Our system revealed that the activities of chronic cholangitis and hepatitis did not correlate with each other in terms of degree and that our staging system properly reflected the outcome of PBC patients. The present study could validate the effectiveness of this new system for characterizing the pathologic condition of PBC.

Prospective evaluation of MR enterography as the primary imaging modality for pediatric Crohn disease assessment.

OBJECTIVE: The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn disease imaging features in pediatric patients, compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard. SUBJECTS AND METHODS: The study group for this blinded prospective study included 21 pediatric subjects with known Crohn disease scheduled for clinical CT and histologic bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by two radiologists and were scored for Crohn disease features. All bowel histology specimens were reviewed by a single pathologist for the presence of active mucosal inflammation and mural fibrosis, followed by correlation of imaging and histologic findings. RESULTS: All 21 subjects underwent MR enterography and histologic sampling, 18 of whom also underwent CT. MR enterography had high sensitivity for detecting Crohn disease imaging features (e.g., bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, and abscess) compared with CT, with individual sensitivity values ranging from 85.1% to 100%. Of a total of 53 abnormal bowel segments with correlation of MRI and histologic findings, MR enterography showed 86.7% accuracy (90.0% sensitivity and 82.6% specificity) for detecting active inflammation (p < 0.001). The accuracy of MR enterography for detecting mural fibrosis overall was 64.9%, compared with histology, but increased to 83.3% (p < 0.05) for detecting fibrosis without superimposed active inflammation. CONCLUSION: MR enterography can substitute for CT as the first-line imaging modality in pediatric patients with Crohn disease, on the basis of its ability to detect intestinal pathologic abnormalities in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.

Monocyte chemoattractant protein-1 derived from biliary innate immunity contributes to hepatic fibrogenesis.

AIMS: Monocyte chemoattractant protein-1 (MCP-1) is a major chemotactic factor for hepatic stellate cells (HSCs) associated with hepatic fibrosis. In this study, among several fibrogenetic factors derived from biliary epithelial cells (BECs), MCP-1 produced by the biliary innate immune system was found to be most critical in the histogenesis of hepatic fibrogenesis. METHODS: Using cultured human BECs, the expression of five fibrogenetic factors including MCP-1 on stimulation with Toll-like receptor ligands, inflammatory cytokines or bile acids was examined. Moreover, in situ detection of MCP-1 and α-smooth muscle actin proteins was performed using sections from normal and diseased livers by immunohistochemistry. RESULTS: All fibrogenetic factors were detected in BECs, but only MCP-1 expression was upregulated, by all the Toll-like receptor ligands, IL-1ß, and tumour necrosis factor-alpha. Proliferating bile ductules in interface areas expressed MCP-1 in diseased livers accompanying α-smooth muscle actin-positive activated HSCs. CONCLUSIONS: Bile ductules proliferate in various hepatobiliary diseases, and its significance is still unknown. This study demonstrated that BECs in bile ductules could produce MCP-1, particularly, via biliary innate immunity, suggesting that MCP-1 derived from BECs plays an important role in the recruitment of HSCs to interface areas and the activation of HSCs resulting in the progression of periportal fibrosis.

Prognosis of invasive intraductal papillary mucinous neoplasm depends on histological and precursor epithelial subtypes.

OBJECTIVE: Invasive cancers arising from intraductal papillary mucinous neoplasm (IPMN) are recognised as a morphologically and biologically heterogeneous group of neoplasms. Less is known about the epithelial subtypes of the precursor IPMN from which these lesions arise. The authors investigate the clinicopathological characteristics and the impact on survival of both the invasive component and its background IPMN. DESIGN AND PATIENTS: The study cohort comprised 61 patients with invasive IPMN (study group) and 570 patients with pancreatic ductal adenocarcinoma (PDAC, control group) resected at a single institution. Multivariate analyses were performed using a stage-matched Cox proportional hazard model. RESULTS: The histology of invasive components of the IPMN cohort was tubular in 38 (62%), colloid in 16 (26%), and oncocytic in seven (12%). Compared with PDAC, invasive IPMNs were associated with a lower incidence of adverse pathological features and improved mortality by multivariate analysis (HR 0.58; 95% CI 0.39 to 0.86). In subtype analysis, this favourable outcome remained only for colloid and oncocytic carcinomas, while tubular adenocarcinoma was associated with worse overall survival, not significantly different from that of PDAC (HR 0.85; 95% CI 0.53 to 1.36). Colloid and oncocytic carcinomas arose only from intestinal- and oncocytic-type IPMNs, respectively, and were mostly of the main-duct type, whereas tubular adenocarcinomas primarily originated in the gastric background, which was often associated with branch-duct IPMN. Overall survival of patients with invasive adenocarcinomas arising from gastric-type IPMN was significantly worse than that of patients with non-gastric-type IPMN (p=0.016). CONCLUSIONS: Tubular, colloid and oncocytic invasive IPMNs have varying prognosis, and arise from different epithelial subtypes. Colloid and oncocytic types have markedly improved biology, whereas the tubular type has a course that resembles PDAC. Analysis of these subtypes indicates that the background epithelium plays an equally, if not more, important role in defining the biology and prognosis of invasive IPMNs.

Significance of periductal Langerhans cells and biliary epithelial cell-derived macrophage inflammatory protein-3α in the pathogenesis of primary biliary cirrhosis.

BACKGROUND/AIMS: To clarify the primary biliary cirrhosis (PBC)-specific antigen-presenting mechanism, we examined the distribution and phenotypic characteristics of infiltrating dendritic cells (DCs) with respect to bile ducts and the mechanism of migration in terms of the periductal cytokine milieu and biliary innate immunity. METHODS AND RESULTS: Immunohistochemistry using liver sections from patients with PBC and controls revealed that blood dendritic cell antigen (BDCA)-2(+) plasmacytoid DCs were found mainly in the portal tracts in PBC and the controls, but their distribution was not related to bile ducts. BDCA-1(+) and CD19(-) myeloid DCs were also found in portal tracts in PBC and the controls and, in particular, Langerin+Langerhans cells (LCs) were dominantly scattered around or within biliary epithelial layers of the damaged bile ducts in PBC. Moreover, experiments with cultured human biliary epithelial cells (BECs) showed that an LC-attracting chemokine, macrophage inflammatory protein-3α, was produced by BECs in the response to cytokines [interleukin (IL)-1ß, tumour necrosis factor-α and IL-17] and pathogen-associated molecular patterns. CONCLUSIONS: LCs existing around or within biliary epithelial layers are important as periductal antigen-presenting cells in PBC and the migration of LCs into bile ducts is closely associated with the periductal cytokine milieu and biliary innate immunity in PBC.

Survival study of natural orifice translumenal endoscopic surgery for rectosigmoid resection using transanal endoscopic microsurgery with or without transgastric endoscopic assistance in a swine model.

BACKGROUND: The feasibility of transanal rectosigmoid resection with transanal endoscopic microsurgery (TEM) was previously demonstrated in a swine nonsurvival model in which transgastric endoscopic assistance also was shown to extend the length of colon mobilized transanally. METHODS: A 2-week survival study evaluating transanal endoscopic rectosigmoid resection with stapled colorectal anastomosis was conducted with swine using the transanal approach alone (TEM group, n = 10) or a transanal approach combined with transgastric endoscopic assistance (TEM + TG group, n = 10). Gastrotomies were created using a needleknife and balloon dilation, then closed using prototype T-tags. Outcomes were evaluated and compared between the groups using Student's t-test and Fisher's exact test. RESULTS: Relative to the TEM group, the average length of rectosigmoid mobilized in the TEM + TG group was 15.6 versus 10.5 cm (p < 0.0005), the length of the resected specimen was 9 versus 6.2 cm (p < 0.0005), and the mean operative time was 254.5 versus 97.5 min (p < 0.0005). Intraoperatively, no organ injury or major bleeding was noted. Two T-tag misfires occurred during gastrotomy closure and four small staple line defects requiring transanal repair including one in the TEM group and three in the TEM + TG group (p = 0.2). Postoperatively, there was no mortality, and the animals gained an average of 3.4 lb. Two major complications (10%) were identified at necropsy in the TEM + TG group including an intraabdominal abscess and an abdominal wall hematoma related to T-tag misfire. Gastrotomy closure sites and colorectal anastomoses were all grossly healed, with adhesions noted in 60 and 70% and microabscesses in 50 and 20% of the gastrotomy sites and colorectal anastomoses, respectively. CONCLUSIONS: Natural orifice translumenal endoscopic surgery (NOTES) for rectosigmoid resection using TEM with or without transgastric endoscopic assistance is feasible and associated with low morbidity in a porcine survival model. Transgastric assistance significantly prolongs the operative time but extends the length of the rectosigmoid mobilized transanally, with a nonsignificant increase in complication rates related to gastrotomy creation.

The clinical significance of incidental chronic colitis: a study of 17 cases.

INTRODUCTION: A histologic diagnosis of chronic colitis raises a relatively limited differential diagnosis that includes inflammatory bowel disease, long-standing infections, and chronic ischemia. In routine clinical practice, inflammatory bowel disease accounts for the majority of cases of chronic colitis. Although a variety of drug-induced injury patterns in the colon have been recognized, there are few well-documented examples of drug-induced chronic colitis. In this study, we report the clinical, histologic, and follow-up data on 17 cases of histologically documented cases of chronic colitis in which a definitive etiologic factor could not be identified. METHODS: Using our electronic databases we recorded all cases of chronic colitis in adults over an 8-year period. Patients with a history (prior or subsequent) of inflammatory bowel disease were excluded. Cases showing histologic features of ischemic, pseudomembranous, or granulomatous colitis were excluded. The biopsies were evaluated and semiquantitatively scored for established histologic features of activity and chronicity. The clinical, endoscopic, and follow-up data, including drug usage, was recorded. RESULTS: There were 10 males and 7 females and the mean age was 59 years. The majority of cases involved the cecum or ascending colon (16 of 17 cases). A majority of patients were asymptomatic (n=11), and in others, indications for colonoscopy were occult blood (n=3), hematochezia (n=2), and melena (n=1). The most common mucosal abnormality was erythema (n=10), ulcers (n=3), congestion (n=3), and edematous mucosa (n=1). All cases showed histologic features of chronicity and showed either basal plasmacytosis (94%) or crypt architectural distortion (94%). Eight (47%) patients reported nonsteroidal anti-inflammatory drugs (NSAID) use. Withdrawal of NSAIDs in 2 cases resulted in normalization of the colonic mucosa. On follow-up, all 17 patients were asymptomatic (median follow-up 42.8 mo) and did not progress to inflammatory bowel disease. CONCLUSIONS: We report a series of 17 histologically documented cases of incidental chronic colitis without a conventional etiology. However, both the frequent usage of NSAIDs, and normalization of mucosal changes after withdrawal of this drug suggest that NSAIDs may account for this cecal-based chronic colitis. The awareness of this histologically dramatic but clinically innocuous form of chronic colitis may avoid errors in mucosal biopsy diagnosis.

Ruptured appendiceal diverticula mimicking low-grade appendiceal mucinous neoplasms.

Low-grade appendiceal mucinous neoplasms may rupture and seed the peritoneum with bland neoplastic mucinous epithelium resulting, when grossly evident, in the well-known process pseudomyxoma peritonei. Appendiceal diverticula may also rupture, resulting in mucin on the appendiceal serosa, which may raise concern for an underlying appendiceal mucinous neoplasm. We report 11 cases of ruptured appendiceal diverticula that were initially either misdiagnosed as appendiceal mucinous neoplasms, raised concern for a neoplasm, or were thought to exhibit localized pseudomyxoma peritonei. Two cases showed eversion of the appendiceal lining onto the serosa; 1 showed collision between the diverticulum and endosalpingiosis, and 3 had rare nonneoplastic epithelial cells in extra-appendiceal mucin. Most cases showed mucosal hyperplasia, mild crypt disarray, and variable reactive atypia. Eight cases had mucosal neuromas or other neural changes. None of the patients progressed to pseudomyxoma peritonei during the follow-up interval (mean 23 mo). Pathologists should be aware that ruptured appendiceal diverticula may be associated with serosal mucin and even extra-appendiceal epithelium. Failure to distinguish this process from a mucosal neoplasm with rupture may result in unnecessary therapy and cause the patient undue alarm.