Disseminated Metacestode Versteria Species Infection in Woman, Pennsylvania, USA1.

A patient in Pennsylvania, USA, with common variable immunodeficiency sought care for fever, cough, and abdominal pain. Imaging revealed lesions involving multiple organs. Liver resection demonstrated necrotizing granulomas, recognizable tegument, and calcareous corpuscles indicative of an invasive cestode infection. Sequencing revealed 98% identity to a Versteria species of cestode found in mink.

Molecular testing for the clinical diagnosis of fibrolamellar carcinoma.

Fibrolamellar carcinoma has a distinctive morphology and immunophenotype, including cytokeratin 7 and CD68 co-expression. Despite the distinct findings, accurate diagnosis of fibrolamellar carcinoma continues to be a challenge. Recently, fibrolamellar carcinomas were found to harbor a characteristic somatic gene fusion, DNAJB1-PRKACA. A break-apart fluorescence in situ hybridization (FISH) assay was designed to detect this fusion event and to examine its diagnostic performance in a large, multicenter, multinational study. Cases initially classified as fibrolamellar carcinoma based on histological features were reviewed from 124 patients. Upon central review, 104 of the 124 cases were classified histologically as typical of fibrolamellar carcinoma, 12 cases as 'possible fibrolamellar carcinoma' and 8 cases as 'unlikely to be fibrolamellar carcinoma'. PRKACA FISH was positive for rearrangement in 102 of 103 (99%) typical fibrolamellar carcinomas, 9 of 12 'possible fibrolamellar carcinomas' and 0 of 8 cases 'unlikely to be fibrolamellar carcinomas'. Within the morphologically typical group of fibrolamellar carcinomas, two tumors with unusual FISH patterns were also identified. Both cases had the fusion gene DNAJB1-PRKACA, but one also had amplification of the fusion gene and one had heterozygous deletion of the normal PRKACA locus. In addition, 88 conventional hepatocellular carcinomas were evaluated with PRKACA FISH and all were negative. These findings demonstrate that FISH for the PRKACA rearrangement is a clinically useful tool to confirm the diagnosis of fibrolamellar carcinoma, with high sensitivity and specificity. A diagnosis of fibrolamellar carcinoma is more accurate when based on morphology plus confirmatory testing than when based on morphology alone.

Hepatic adenomas with synchronous or metachronous fibrolamellar carcinomas: both are characterized by LFABP loss.

Rare hepatic adenomas are associated with synchronous or metachronous fibrolamellar carcinomas. The morphology of these adenomas has not been well described and they have not been subclassifed using the current molecular classification schema. We examined four hepatic adenomas co-occurring with or preceding a diagnosis of fibrolamellar carcinoma in three patients. On histological examination, three of the adenomas showed the typical morphology of HNF1-α inactivated adenomas, whereas one showed a myxoid adenoma morphology. All of the adenomas were negative for PRKACA rearrangements by Fluorescence in situ Hybridization (FISH) analysis. All four of the adenomas showed complete loss or significant reduction of liver fatty acid binding protein (LFABP) expression by immunohistochemistry. Interestingly, the fibrolamellar carcinomas in each case also showed loss of LFABP by immunohistochemistry. One of the fibrolamellar carcinomas was negative for PRKACA rearrangements by FISH, whereas the others were positive. To investigate if LFBAP loss is typical of fibrolamellar carcinomas in general, an additional cohort of tumors was studied (n=19). All 19 fibrolamellar carcinomas showed the expected PRKACA rearrangements and immunostains showed loss of LFABP in each case, consistent with HNF1-α inactivation. To validate this observation, mass spectrometry-based proteomics was performed on tumor-normal pairs of six fibrolamellar carcinomas and showed an average 10-fold reduction in LFABP protein levels, compared with matched normal liver tissue. In conclusion, hepatic adenomas co-occurring with fibrolamellar carcinomas show LFABP loss and are negative for PRKACA rearrangements, indicating they are genetically distinct lesions. These data also demonstrate that LFABP loss, which characterizes HNF1-α inactivation, is a consistent feature of fibrolamellar carcinoma, indicating HNF1-α inactivation is an important event in fibrolamellar carcinoma pathogenesis.

Revisiting the cytologic features of autoimmune pancreatitis: An institutional experience.

BACKGROUND: Autoimmune pancreatitis (AIP) is a known mimicker of pancreatic ductal adenocarcinoma both clinically and radiologically. In this study, the authors present their institutional experience in diagnosing AIP on cytology and correlate results with the histologic findings. METHODS: A 14-year computerized search for patients who had histologically confirmed AIP with concurrent or prior cytology was performed. Clinical data, cytology findings, and surgical pathology results were reviewed for analysis. RESULTS: Eighteen patients were identified. The patients showed a male predominance, with a mean age of 59 years. Jaundice, weight loss, and abdominal pain were the most common clinical presentation. Five of 12 patients who were tested for serum immunoglobulin G4 had elevated levels. Cytologic findings of 16 cases that were available for review showed markedly inflamed fibrous stroma (54%) and cytologic atypia (50%). The final cytologic diagnoses were suspicious for adenocarcinoma (n = 1), atypical (n = 8), and benign/negative (n = 9). The corresponding surgical pathology diagnoses were classified as type 1 (n = 10), type 2 (n = 6), and AIP, not otherwise specified (n = 2). All type 2 AIP cases had at least atypical cytologic diagnoses, with one called suspicious for adenocarcinoma and another called adenocarcinoma at the time of rapid on-site evaluation. In contrast, eight of 10 type 1 AIP cases were negative/benign, and two of 10 were atypical. In these two atypical cases, the possibility of AIP was raised because of the presence of inflamed stroma. CONCLUSION: AIP is a pitfall in cytology because moderate-to-marked atypia can be present, especially in type 2 AIP. Because atypia can be severe, the presence of cellular fibrous stroma with lymphocytic stromal infiltrates and the integration of serum immunoglobulin G4 levels could be helpful in avoiding diagnostic overcall in AIP.

Chronically inflamed livers up-regulate expression of inhibitory B7 family members.

UNLABELLED: Hepatitis B virus, hepatitis C virus, autoimmune hepatitis, and nonalcoholic fatty liver disease can induce chronic liver disease. The Programmed Death-1 (PD-1) inhibitory pathway assists in T cell response regulation during acute and chronic inflammation and participates in the progression of inflammatory liver disease. To examine whether PD-1 and its ligands, B7-H1 and B7-DC, are modulated during chronic necroinflammatory liver disease, we investigated expression profiles in normal patients and patients with the aforementioned conditions. Relative to liver biopsies from normal individuals, those from patients with chronic necroinflammatory liver diseases (hepatitis B virus, hepatitis C virus, and autoimmune hepatitis) contain increased numbers of PD-1-expressing lymphocytes. Kupffer cells, liver sinusoidal endothelial cells, and leukocytes express PD-1 ligands. We also detect PD-1 ligands on hepatocytes within biopsies and on isolated cells. All forms of chronic necroinflammatory liver disease examined correlate with increased B7-H1 and B7-DC expression on Kupffer cells, liver sinusoidal epithelial cells, and leukocytes. The degree of necroinflammation correlates with expression levels of PD-1 family members. CONCLUSION: These results demonstrate that expression of PD-1/PD-1 ligands links more directly with the degree of inflammation than with the underlying etiology of liver damage. The PD-1 pathway may assist the liver in protecting itself from immune-mediated destruction.

Paraduodenal inflammatory pseudotumor masquerading as malignancy.

A 30-year-old woman presented with severe abdominal pain and abdominal distension. CT demonstrated two intra-abdominal masses, one involving the left lateral segment of the liver and the other adjacent to the duodenum. Initial biopsies were consistent with focal nodular hyperplasia of the liver and non-specific lymphocytic infiltrate in the paraduodenal mass. Due to persistent symptoms, the patient underwent laparoscopic resection of the paraduodenal mass. Final pathology was consistent with an inflammatory pseudotumour and the patient's symptoms subsequently resolved.

Immunohistochemistry in Acute Myeloid Leukemia.

The World Health Organization's Classification of Tumours of Haematopoietic and Lymphoid Tissues (Swerdlow et al. (eds) WHO Classification of tumours of haematopoietic and lymphoid tissues, 4th edn. WHO Press, Lyon, 2008) created a classification scheme incorporating genetic, molecular, morphologic, and immunophenotypic characteristics. The diagnosis of acute myeloid leukemia requires equal to or greater than 20% blasts (except in some cases with specific cytogenetic abnormalities or in erythroleukemia). The diagnostic work up typically includes morphologic, cytochemical, and immunophenotypic features. This generally includes evaluation of the peripheral blood, bone marrow aspirate, and bone marrow trephine biopsy. As stated in the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, "the contribution of an adequate bone marrow biopsy cannot be over stated" (Swerdlow et al. (eds) WHO Classification of tumours of haematopoietic and lymphoid tissues, 4th edn. WHO Press, Lyon, 2008). The evaluation of the bone marrow biopsy provided the necessary material for immunohistochemical studies used for both diagnosis and prognosis.The following text will focus on the utilization of immunohistochemical studies in the classification of acute myeloid leukemia. Other methodologies will be discussed elsewhere in this volume.

Increased Fas ligand expression of CD4+ T cells by HCV core induces T cell-dependent hepatic inflammation.

Hepatitis C virus (HCV) infection is associated with a high rate of viral persistence and the development of chronic liver disease. The expression of HCV core protein in T cells has previously been reported to alter T cell activation and has been linked to the development of liver inflammation. However, the molecular and cellular basis for the role of HCV core-expressing T cells in liver inflammation is not understood. Here, using double-transgenic mice of CD2/HCV-core transgenic mice and ovalbumin (OVA)-specific T cell receptor transgenic mice, we demonstrated that in vivo antigenic stimulation (OVA peptide administration) triggers a marked influx of core-expressing, antigen-specific, transgenic CD4+ T cells into the liver of these mice. Phenotypic analysis of the liver-infiltrating T cells revealed high expression levels of CD44 and Fas ligand (FasL). Adoptive transfer of liver-infiltrating, core-expressing CD4+ T cells into severe combined immunodeficiency mice directly demonstrated the capacity of these activated T cells to induce liver inflammation. It is important that anti-FasL antibody treatment of the mice at the time of cell transfer abrogated the liver inflammation induced by core-expressing CD4+ T cells. These findings suggest that activated T lymphocytes expressing elevated levels of FasL may be involved in the bystander killing of hepatocyte, as well as the induction of chronic liver inflammation, by promoting recruitment of proinflammatory cells to the liver.

Upper GI tract lesions in familial adenomatous polyposis (FAP): enrichment of pyloric gland adenomas and other gastric and duodenal neoplasms.

Patients with familial adenomatous polyposis (FAP), an autosomal dominant cancer predisposition syndrome caused by mutations in the APC gene, develop neoplasms in both the upper and lower gastrointestinal (GI) tract. To clarify the upper GI tract lesions in FAP patients in a tertiary care setting, we reviewed specimens from 321 endoscopies in 66 patients with FAP. Tubular adenomas in the small bowel were the most common neoplasms (present in 89% of patients), although only 1 patient developed invasive carcinoma of the small bowel. Several types of gastric neoplasms were identified--65% of patients had at least 1 fundic gland polyp, and 23% of patients had at least 1 gastric foveolar-type gastric adenoma. Pyloric gland adenomas were also enriched, occurring in 6% of patients--this is a novel finding in FAP patients. Despite the high frequency of gastric neoplasms, only 1 patient developed carcinoma in the stomach. The very low frequency of carcinoma in these patients suggests that current screening procedures prevent the vast majority of upper GI tract carcinomas in patients with FAP, at least in the tertiary care setting.

Lichenoid esophagitis: clinicopathologic overlap with established esophageal lichen planus.

Lichen planus (LP) affects mucocutaneous surfaces and is characterized by intraepithelial and lamina propria lymphocytosis and squamous cell apoptosis (Civatte bodies). Lichen planus esophagitis (LPE) is underrecognized; concurrent cutaneous disease is present in some patients, but LPE alone is more common. We diagnose patients with characteristic pathologic findings of LPE and known correlation with skin disease or immunofluorescence (IF) results as LPE but use descriptive terminology ("lichenoid esophagitis pattern" [LEP]) when confirmation is unavailable. We reviewed clinicopathologic features of patients diagnosed at our institution with LPE or LEP. There were 88 specimens with LPE or LEP from 65 patients. Most patients were female. Seventeen patients had LPE confirmed by IF. Five patients had both esophageal (1 with IF) and skin LP. Strictures were a prominent presenting feature in LPE patients, with disease distribution more frequent in the upper and lower esophagus. Dysphagia was a common reason for endoscopy in LEP patients. Rheumatologic diseases are more common in patients with LPE compared with LEP. Viral hepatitides and human immunodeficiency virus (HIV) infections are associated with LEP. We defined polypharmacy as patients taking >3 medications; this finding was present in both LPE and LEP cohorts; however, this is a prominent feature in those with established LPE. Progression to dysplasia was noted in both cohorts. About 5% of LPE patients have tandem skin manifestations. LPE is more likely than LEP to arise in women, result in stricture formation, and be associated with rheumatologic disorders and polypharmacy, whereas LEP is associated with viral hepatitis and HIV. Both can progress to neoplasia. As the risk of stricture formation is high in patients with LPE, it is worth performing pertinent IF studies to confirm LPE, although knowledge of the clinical association of LEP with viral hepatitis, HIV, and use of multiple medications is of value in daily practice.

Immunohistochemical staining for TLE1 distinguishes synovial sarcoma from histologic mimics.

Transducer-like enhancer of split 1 (TLE1) is overexpressed in synovial sarcomas. We investigated TLE1 expression by immunohistochemical analysis in a well-characterized series of synovial sarcomas and other mesenchymal tumors most commonly considered in the differential diagnosis. Whole tissue sections of 212 tumors were evaluated: 73 synovial sarcomas (23 biphasic, 28 monophasic, 22 poorly differentiated), 47 malignant peripheral nerve sheath tumors (MPNSTs), 49 solitary fibrous tumors (SFTs), 20 fibrosarcomatous variants of dermatofibrosarcoma protuberans, and 23 Ewing sarcomas/primitive neuroectodermal tumors (PNETs). All monophasic and poorly differentiated SSs and Ewing sarcoma/PNETs were previously confirmed to harbor t(X;18) and EWSR1 gene rearrangements, respectively. In total, 60 (82%) of 73 synovial sarcomas were positive for TLE1, including 18 biphasic (78%), 22 monophasic (79%), and 20 poorly differentiated (91%) tumors. Of the other tumors, only 7 MPNSTs (15%) and 4 SFTs (8%) were positive for TLE1, most of which showed only weak staining. TLE1 is a sensitive and specific marker for synovial sarcoma and can be helpful to distinguish synovial sarcoma from histologic mimics, particularly if moderate or strong staining is observed. In this study, only a small subset of MPNSTs and SFTs showed limited staining for TLE1.

Blockade of PD-1/B7-H1 interaction restores effector CD8+ T cell responses in a hepatitis C virus core murine model.

The impaired function of CD8(+) T cells is characteristic of hepatitis C virus (HCV) persistent infection. HCV core protein has been reported to inhibit CD8(+) T cell responses. To determine the mechanism of the HCV core in suppressing Ag-specific CD8(+) T cell responses, we generated a transgenic mouse, core(+) mice, where the expression of core protein is directed to the liver using the albumin promoter. Using a recombinant adenovirus to deliver Ag, we demonstrated that core(+) mice failed to clear adenovirus-LacZ (Ad-LacZ) infection in the liver. The effector function of LacZ-specific CD8(+) T cells was particularly impaired in the livers of core(+) mice, with suppression of IFN-gamma, TNF-alpha, and granzyme B production by CD8(+) T cells. In addition, the impaired CD8(+) T cell responses in core(+) mice were accompanied by the enhanced expression of the inhibitory receptor programmed death-1 (PD-1) by LacZ-specific CD8(+) T cells and its ligand B7-H1 on liver dendritic cells following Ad-LacZ infection. Importantly, blockade of the PD-1/B7-H1 inhibitory pathway (using a B7-H1 blocking antibody) in core(+) mice enhanced effector function of CD8(+) T cells and cleared Ad-LacZ-infection as compared with that in mice treated with control Ab. This suggests that the regulation of the PD-1/B7-H1 inhibitory pathway is crucial for HCV core-mediated impaired T cell responses and viral persistence in the liver. This also suggests that manipulation of the PD-1/B7-H1 pathway may be a potential immunotherapy to enhance effector T cell responses during persistent HCV infection.

Fas ligand is responsible for CXCR3 chemokine induction in CD4+ T cell-dependent liver damage.

Immune-mediated hepatic damage has been demonstrated in the pathogenesis of hepatitis C virus (HCV) and other hepatotrophic infections. Fas/Fas ligand (FasL) interaction plays a critical role in immune-mediated hepatic damage. To understand the molecular mechanism(s) of FasL-mediated liver inflammation, we examined the effect of CD4(+) T cells expressing high levels of FasL on the initiation of hepatic damage through analysis of chemokine and chemokine receptor expression in HCV core x TCR (DO11.10) double-transgenic mice. In vivo antigenic stimulation triggers a marked influx of core-expressing Ag-specific CD4(+) T cells into the liver of the immunized core(+) TCR mice but not their core(-) TCR littermates. Strikingly, the inflammatory process in the liver of core(+) TCR mice was accompanied by a dramatic increase in IFN-inducible protein 10 and monokine induced by IFN-gamma production. The intrahepatic lymphocytes were primarily CXCR3-positive and anti-CXCR3 Ab treatment abrogates migration of CXCR3(+) lymphocytes into the liver and hepatic damage. Importantly, the blockade of Fas/FasL interaction reduces the expression of IFN-inducible protein 10 and monokine induced by IFN-gamma and cellular infiltration into the liver. These findings suggest that activated CD4(+) T cells with elevated FasL expression are involved in promoting liver inflammation and hepatic damage through the induction of chemokines.

gC1q receptor ligation selectively down-regulates human IL-12 production through activation of the phosphoinositide 3-kinase pathway.

gC1qR, a complement receptor for C1q, plays a pivotal role in the regulation of inflammatory and antiviral T cell responses. Several pathogens, including hepatitis C virus, exploit gC1qR-dependent regulatory pathways to manipulate host immunity. However, the molecular mechanism(s) of gC1qR signaling involved in regulating inflammatory responses remains unknown. We report the selective inhibition of TLR4-induced IL-12 production after cross-linking of gC1qR on the surface of macrophages and dendritic cells. Suppression of IL-12 did not result from increased IL-10 or TGF-beta, but was dependent on PI3K activation. Activation of PI3K and subsequent phosphorylation of Akt define an intracellular pathway mediating gC1qR signaling and cross-talk with TLR4 signaling. This is the first report to identify signaling pathways used by gC1qR-mediated immune suppression, and it establishes a means of complement-mediated immune suppression to inhibit Th1 immunity crucial for clearing pathogenic infection.

SOCS1 and SOCS3 are targeted by hepatitis C virus core/gC1qR ligation to inhibit T-cell function.

T cells play an important role in the control of hepatitis C virus (HCV) infection. We have previously demonstrated that the HCV core inhibits T-cell responses through interaction with gC1qR. We show here that core proteins from chronic and resolved HCV patients differ in sequence, gC1qR-binding ability, and T-cell inhibition. Specifically, chronic core isolates bind to gC1qR more efficiently and inhibit T-cell proliferation as well as gamma interferon (IFN-gamma) production more profoundly than resolved core isolates. This inhibition is mediated by the disruption of STAT phosphorylation through the induction of SOCS molecules. Silencing either SOCS1 or SOCS3 by small interfering RNA dramatically augments the production of IFN-gamma in T cells, thereby abrogating the inhibitory effect of core. Additionally, the ability of core proteins from patients with chronic infections to induce SOCS proteins and suppress STAT activation greatly exceeds that of core proteins from patients with resolved infections. These results suggest that the HCV core/gC1qR-induced T-cell dysfunction involves the induction of SOCS, a powerful inhibitor of cytokine signaling, which represents a novel mechanism by which a virus usurps the host machinery for persistence.