Multi-Center Follow-up Study to Develop a Classification System Which Differentiates Mucinous Cystic Neoplasm of the Liver and Benign Hepatic Cyst Using Machine Learning

RATIONALE AND OBJECTIVES

To date, no clinically useful classification system has been developed for reliably differentiating mucinous cystic neoplasm (MCN) from a benign hepatic cyst (BHC) in the liver. The objective was to use machine learning and a multi-center study design to develop and assess the performance of a novel classification system for predicting whether a hepatic cystic lesion represents MCN or BHC.

MATERIALS AND METHODS

A multi-center cohort study identified 154 surgically resected hepatic cystic lesions in 154 subjects which were pathologic confirmed as MCN (43) or BHC (111). Readers at each institution recorded seven pre-determined imaging features previously identified as potential differentiating features from prior publications. The contribution of each of these features to differentiating MCN from BHC was assessed by machine learning to develop an optimal classification system.

RESULTS

Although several of the assessed imaging features demonstrated statistical significance, only 3 imaging features were found by machine learning to significantly contribute to a potential classification system: (1) solid enhancing nodule (2) all septations arising from an external macro-lobulation (3) whether the lesion was solitary or one of multiple cystic liver lesions. The optimal classification system had only four categories and correctly identified 144/154 lesion (93.5%).

CONCLUSION

This multi-center follow-up study was able to use machine learning to develop a highly accurate classification system for differentiation of hepatic MCN from BHC, which could be readily applied to clinical practice.

Integrating microarray-based spatial transcriptomics and single-cell RNA-seq reveals tissue architecture in pancreatic ductal adenocarcinomas

Single-cell RNA sequencing (scRNA-seq) enables the systematic identification of cell populations in a tissue, but characterizing their spatial organization remains challenging. We combine a microarray-based spatial transcriptomics method that reveals spatial patterns of gene expression using an array of spots, each capturing the transcriptomes of multiple adjacent cells, with scRNA-Seq generated from the same sample. To annotate the precise cellular composition of distinct tissue regions, we introduce a method for multimodal intersection analysis. Applying multimodal intersection analysis to primary pancreatic tumors, we find that subpopulations of ductal cells, macrophages, dendritic cells and cancer cells have spatially restricted enrichments, as well as distinct coenrichments with other cell types. Furthermore, we identify colocalization of inflammatory fibroblasts and cancer cells expressing a stress-response gene module. Our approach for mapping the architecture of scRNA-seq-defined subpopulations can be applied to reveal the interactions inherent to complex tissues.

Crosstalk between Regulatory T Cells and Tumor-Associated Dendritic Cells Negates Anti-tumor Immunity in Pancreatic Cancer

Regulatory T (Treg) cell infiltration constitutes a prominent feature of pancreatic ductal adenocarcinoma (PDA). However, the immunomodulatory function of Treg cells in PDA is poorly understood. Here, we demonstrate that Treg cell ablation is sufficient to evoke effective anti-tumor immune response in early and advanced pancreatic tumorigenesis in mice. This response is dependent on interferon-γ (IFN-γ)-producing cytotoxic CD8⁺ T cells. We show that Treg cells engage in extended interactions with tumor-associated CD11c⁺ dendritic cells (DCs) and restrain their immunogenic function by suppressing the expression of costimulatory ligands necessary for CD8⁺ T cell activation. Consequently, tumor-associated CD8⁺ T cells fail to display effector activities when Treg cell ablation is combined with DC depletion. We propose that tumor-infiltrating Treg cells can promote immune tolerance by suppressing tumor-associated DC immunogenicity. The therapeutic manipulation of this axis might provide an effective approach for the targeting of PDA.

Targeting Poxvirus Decapping Enzymes and mRNA Decay to Generate an Effective Oncolytic Virus

Through the action of two virus-encoded decapping enzymes (D9 and D10) that remove protective caps from mRNA 5′-termini, Vaccinia virus (VACV) accelerates mRNA decay and limits activation of host defenses. D9- or D10-deficient VACV are markedly attenuated in mice and fail to counter cellular double-stranded RNA-responsive innate immune effectors, including PKR. Here, we capitalize upon this phenotype and demonstrate that VACV deficient in either decapping enzyme are effective oncolytic viruses. Significantly, D9- or D10-deficient VACV displayed anti-tumor activity against syngeneic mouse tumors of different genetic backgrounds and human hepatocellular carcinoma xenografts. Furthermore, D9- and D10-deficient VACV hyperactivated the host anti-viral enzyme PKR in non-tumorigenic cells compared to wild-type virus. This establishes a new genetic platform for oncolytic VACV development that is deficient for a major pathogenesis determinant while retaining viral genes that support robust productive replication like those required for nucleotide metabolism. It further demonstrates how VACV mutants unable to execute a fundamental step in virus-induced mRNA decay can be unexpectedly translated into a powerful anti-tumor therapy.

Paget's disease of the anus masking a mixed adenoneuroendocrine tumour of the rectum

A man aged 83 years with vague perirectal symptoms had a delayed diagnosis of Paget's disease of the anus. A lack of thorough digital rectal examination failed to diagnose a mixed adenonueroendocrine tumour of the rectum in a timely matter.

Abstract A100: Crosstalk between regulatory T cells and tumor-associated dendritic cells controls antitumor immunity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) is marked by an abundant fibroinflammatory microenvironment. Regulatory T (Treg) cell infiltration constitutes a prominent feature of PDA. However, the immunomodulatory function of Treg cells in PDA remains poorly understood. Using orthotopic and autochthonous mouse models of PDA we have found that Treg cell ablation is sufficient to evoke effective anti-tumor immune response in early and advanced pancreatic neoplasia. This response is dependent on IFN-γ producing cytotoxic CD8+ T cells. We show that Treg cells engage in extended interactions with tumor-associated CD11c+ dendritic cells (DCs) and restrain their immunogenic function by suppressing the expression of costimulatory ligands necessary for CD8+ T cell activation. Consequently, tumor-associated CD8+ T cells fail to display effector activities when Treg cell ablation is combined with DC depletion. We propose that tumor-infiltrating Treg cells promote immune-tolerance by suppressing DC immunogenicity. Therapeutic manipulation this axis might provide an effective approach for the targeting of PDA.

Citation Format: Jung-Eun Jang, Cristina H. Hajdu, George Miller, Michael L. Dustin, Dafna Bar-Sagi. Crosstalk between regulatory T cells and tumor-associated dendritic cells controls antitumor immunity in pancreatic cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A100.

Direct acting antiviral therapy is curative for chronic hepatitis C/autoimmune hepatitis overlap syndrome

Autoimmune phenomena are common in patients with chronic hepatitis C. Management of chronic hepatitis C/autoimmune hepatitis syndrome has until recently been problematic due to the adverse effects of interferon on autoimmune processes and immunosuppression on viral replication. In this report we describe 3 patients with chronic hepatitis C/autoimmune hepatitis overlap syndrome who responded rapidly to direct acting anti-viral therapy. The resolution of the autoimmune process supports a direct viral role in its pathophysiology.

IL35-Producing B Cells Promote the Development of Pancreatic Neoplasia

A salient feature of pancreatic ductal adenocarcinoma (PDAC) is an abundant fibroinflammatory response characterized by the recruitment of immune and mesenchymal cells and the consequent establishment of a protumorigenic microenvironment. Here, we report the prominent presence of B cells in human pancreatic intraepithelial neoplasia and PDAC lesions as well as in oncogenic Kras-driven pancreatic neoplasms in the mouse. The growth of orthotopic pancreatic neoplasms harboring oncogenic Kras was significantly compromised in B-cell-deficient mice (μMT), and this growth deficiency could be rescued by the reconstitution of a CD1d(hi)CD5(+) B-cell subset. The protumorigenic effect of B cells was mediated by their expression of IL35 through a mechanism involving IL35-mediated stimulation of tumor cell proliferation. Our results identify a previously unrecognized role for IL35-producing CD1d(hi)CD5(+) B cells in the pathogenesis of pancreatic cancer and underscore the potential significance of a B-cell/IL35 axis as a therapeutic target.

SIGNIFICANCE

This study identifies a B-cell subpopulation that accumulates in the pancreatic parenchyma during early neoplasia and is required to support tumor cell growth. Our findings provide a rationale for exploring B-cell-based targeting approaches for the treatment of pancreatic cancer.

Comparison of MRI features of pathologically proven hepatocellular carcinoma between patients with hepatitis B and hepatitis C infection

PURPOSE

To compare MRI features of pathologically-proven hepatocellular carcinoma (HCC) between patients with hepatitis B (HBV) and hepatitis C (HCV) infection.

METHODS

Two radiologists assessed 51 confirmed HCCs on MRI in HBV (n=18) or HCV (n=33) patients; a third, more experienced, radiologist resolved discrepancies.

RESULTS

Arterial hyperenhancement occurred more frequently in HCV (90.9% vs. 66.7%; P=.032), DWI/T2WI hyperintensity more frequently in HBV [(DWI: 78.6% vs. 45.8%, T2WI: 77.8% vs. 48.5%; P=.073-0.088)]. Tumors were larger in HBV (P≤.016). Washout, pseudocapsule, homogeneity, circumscribed margins, lipid, iron, and visually low ADC were not different.

CONCLUSION

Larger studies are required to confirm these preliminary findings.

Utility of diffusion-weighted MRI for differentiating acute from chronic cholecystitis

PURPOSE

To assess the use of diffusion-weighted imaging (DWI) for differentiating acute from chronic cholecystitis, in comparison with conventional magnetic resonance imaging (MRI) features.

MATERIALS AND METHODS

Liver MRI including DWI (b-values 0/500/1000s/mm(2) ) was performed at 1.5T ≤30 days before cholecystectomy in 83 patients with abdominal pain. Two radiologists assessed cases for conventional (gallstones, wall thickening, pericholecystic fluid, pericholecystic fat changes, gallbladder distension, pericholecystic liver enhancement, mural T2 -hyperintensity, mural hyperenhancement, mural striations, abscess, intraluminal membranes, and mural defect) and DWI (increased mural signal on high b-value images, visually low apparent diffusion coefficient [ADC], and ADC values) features.

RESULTS

Acute cholecystitis was present in 43%; chronic cholecystitis was present in 57%. Nine of 12 conventional features were more frequent in acute cholecystitis for both readers (P ≤ 0.003). Increased mural signal on high b-value images was more frequent (P < 0.001) in acute than chronic cholecystitis for R1 (92% vs. 32%) and R2 (83% vs. 30%). Sensitivity and specificity of increased signal on high b-value images were: R1, 92%/68%; R2, 83%/70%. Visually low ADC was more frequent in acute cholecystitis for R2 (P < 0.001) but not R1 (P = 0.406); ADC values were not different between groups for either reader (P = 0.104-0.139). Among conventional and DWI features, only increased signal on high b-value DWI was independently associated with acute cholecystitis for both readers (P = 0.006-0.012).

CONCLUSION

Visually increased mural signal on high b-value DWI was highly sensitive and moderately specific for acute cholecystitis, being an independent predictor relative to conventional features for both readers. Although requiring larger studies, DWI (particularly the high b-value images) may have additive value relative to conventional MRI-suspected acute cholecystitis. J. Magn. Reson. Imaging 2016;44:89-97.

Solitary fibrous tumor of the pancreas

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms of fibroblastic origin. Most commonly they affect the pleura but they been described in other viscera. SFT of the pancreas is extremely rare, and only eight cases have been reported to date. We perform a literature review and report a ninth case. The patient is a 54-year-old African-American female who presented with several months of abdominal pain. Abdominal radiography demonstrated a lesion in the head of the pancreas, and she underwent a Whipple operation. Pathology demonstrated SFT of the pancreas. She is alive and well 1 year post-operatively. SFT of the pancreas predominately affects middle-aged women. These tumors are difficult to distinguish radiologically from neuroendocrine tumors. While SFT of the pancreas tend to have an indolent course, there is the potential for malignancy. We recommend complete surgical excision.

Differentiation of Malignant Omental Caking from Benign Omental Thickening using MRI

PURPOSE

To determine multi-parametric MRI features that can help differentiate malignant omental caking from benign omental thickening in the setting of portal hypertension.

METHODS

We identified 19 patients with an abnormal omentum on MRI and an available reference standard: 11 patients with portal hypertension and benign omental thickening (9 male, 2 female, mean age 58 ± 6 years) and 8 patients with metastatic omental caking (4 male, 4 female, mean age 61 ± 13 years). Criteria for benign omental thickening were no evidence of malignancy for at least 24 months of follow-up (n = 7), negative ascites cytology (n = 2), or absence of malignancy on pathologic analysis of liver explant (n = 2). Criteria for omental malignancy were positive omental biopsy (n = 6) or ascites cytology (n = 2). Two radiologists (R1 and R2) evaluated characteristics of the thickened omentum on MRI.

RESULTS

Findings occurring with significantly higher frequency in malignant omental caking were hyperintensity on high b-value diffusion-weighted imaging (DWI) (R1 88% vs. 0%, R2 88% vs. 0%), hyperenhancement (R1 75% vs. 0%, R2 75% vs. 0%), and convex outer omental contour (R1 88% vs. 0%, R2 75% vs. 9%) (all p ≤ 0.001); discrete omental nodules were significantly more frequent in malignant omental thickening for R1 (63% vs. 0%, p = 0.005). Features not significantly different between groups included decreased ADC, T2 hyperintensity, vessels coursing through the omentum, moderate/large volume ascites, splenomegaly, and mesenteric edema (all p ≥ 0.058).

CONCLUSION

Abnormal signal on DWI, hyperenhancement, and convex outer contour are helpful MRI features to differentiate malignant from benign omental thickening.

Pancreatic cancer: lack of association between apparent diffusion coefficient values and adverse pathological features

AIM

To identify retrospectively potential associations between apparent diffusion coefficient (ADC) values of pancreatic adenocarcinoma and tumour grade as well as other pathological features, using histopathological assessment from the Whipple procedure as the reference standard.

MATERIALS AND METHODS

Thirty patients with pancreatic adenocarcinoma underwent magnetic resonance imaging (MRI) including diffusion-weighted imaging with b-values of 0 and 500 s/mm(2) before the Whipple procedure. Two radiologists independently recorded the ADC values of the tumour and benign pancreas for all cases. ADC values were compared with histopathological findings following the Whipple procedure.

RESULTS

The intra-class correlation coefficient was 0.689 for benign pancreas and 0.695 for tumours, indicating good inter-reader agreement for ADC values. The mean ADC value was significantly lower in tumours than in benign pancreas for both readers (reader 1: 1.74 ± 0.34 × 10(-3) mm(2)/s versus 2.08 ± 0.48 × 10(-3) mm(2)/s, respectively, p = 0.006; reader 2: 1.69 ± 0.41 × 10(-3) mm(2)/s versus 2.11 ± 0.54 × 10(-3) mm(2)/s, respectively, p < 0.001). However, there was no significant difference in mean ADC between poorly and well/moderately differentiated tumours for either reader (reader 1: 1.69 ± 0.36 × 10(-3) mm(2)/s versus 1.78 ± 0.33 × 10(-3) mm(2)/s, respectively, p = 0.491; reader 2: 1.62 ± 0.33 × 10(-3) mm(2)/s versus 1.75 ± 0.49 × 10(-3) mm(2)/s, respectively, p = 0.405). The area under the curve (AUC) for differentiation of poorly and well/moderately differentiated tumours was 0.611 and 0.596 for readers 1 and 2, respectively, and was not significantly better than an AUC of 0.500 for either reader (p ≥ 0.306). In addition, ADC was not significantly different for either reader between tumours with stage T3 versus stage T1/T2, between tumours with and without metastatic peri-pancreatic lymph nodes, or between tumours located in the pancreatic head versus other pancreatic regions (p ≥ 0.413).

CONCLUSION

No associations between ADC values of pancreatic adenocarcinoma and tumour grade or other adverse pathological features were observed.

MyD88 inhibition amplifies dendritic cell capacity to promote pancreatic carcinogenesis via Th2 cells

The transition of chronic pancreatic fibroinflammatory disease to neoplasia is a primary example of the paradigm linking inflammation to carcinogenesis. However, the cellular and molecular mediators bridging these entities are not well understood. Because TLR4 ligation can exacerbate pancreatic inflammation, we postulated that TLR4 activation drives pancreatic carcinogenesis. In this study, we show that lipopolysaccharide accelerates pancreatic tumorigenesis, whereas TLR4 inhibition is protective. Furthermore, blockade of the MyD88-independent TRIF pathway is protective against pancreatic cancer, whereas blockade of the MyD88-dependent pathway surprisingly exacerbates pancreatic inflammation and malignant progression. The protumorigenic and fibroinflammatory effects of MyD88 inhibition are mediated by dendritic cells (DCs), which induce pancreatic antigen-restricted Th2-deviated CD4(+) T cells and promote the transition from pancreatitis to carcinoma. Our data implicate a primary role for DCs in pancreatic carcinogenesis and illustrate divergent pathways in which blockade of TLR4 signaling via TRIF is protective against pancreatic cancer and, conversely, MyD88 inhibition exacerbates pancreatic inflammation and neoplastic transformation by augmenting the DC-Th2 axis.

Assessment of hepatocellular carcinoma using apparent diffusion coefficient and diffusion kurtosis indices: preliminary experience in fresh liver explants

OBJECTIVES

The objective was to perform ex vivo evaluation of non-Gaussian diffusion kurtosis imaging (DKI) for assessment of hepatocellular carcinoma (HCC), including presence of treatment-related necrosis, using fresh liver explants.

METHODS

Twelve liver explants underwent 1.5-T magnetic resonance imaging using a DKI sequence with maximal b-value of 2000 s/mm(2). A standard monoexponential fit was used to calculate apparent diffusion coefficient (ADC), and a non-Gaussian kurtosis fit was used to calculate K, a measure of excess kurtosis of diffusion, and D, a corrected diffusion coefficient accounting for this non-Gaussian behavior. The mean value of these parameters was measured for 16 HCCs based upon histologic findings. For each metric, HCC-to-liver contrast was calculated, and coefficient of variation (CV) was computed for voxels within the lesion as an indicator of heterogeneity. A single hepatopathologist determined HCC necrosis and cellularity.

RESULTS

The 16 HCCs demonstrated intermediate-to-substantial excess diffusional kurtosis, and mean corrected diffusion coefficient D was 23% greater than mean ADC (P=.002). HCC-to-liver contrast and CV of HCC were greater for K than ADC or D, although these differences were significant only for CV of HCCs (P≤.046). ADC, D and K all showed significant differences between non-, partially and completely necrotic HCCs (P≤.004). Among seven nonnecrotic HCCs, cellularity showed a strong inverse correlation with ADC (r=-0.80), a weaker inverse correlation with D (-0.24) and a direct correlation with K (r=0.48).

CONCLUSIONS

We observed non-Gaussian diffusion behavior for HCCs ex vivo; this DKI model may have added value in HCC characterization in comparison with a standard monoexponential model of diffusion-weighted imaging.

Hepatocellular carcinoma: detection with diffusion-weighted versus contrast-enhanced magnetic resonance imaging in pretransplant patients

This study evaluates the performance of diffusion-weighted magnetic resonance imaging (DWI) for the detection of hepatocellular carcinoma (HCC) in pre-liver transplantation patients, compared and combined with contrast-enhanced T1-weighted imaging (CET1WI), using liver explant as the standard of reference. We included 52 patients with cirrhosis (40 men, 12 women; mean age, 56 years) who underwent DWI and CET1WI within 90 days of liver transplantation. Magnetic resonance images were analyzed for HCC detection in three separate sessions by two independent observers: DWI images (DW-set), CET1WI (CE-set), and all images together (All-set). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), per-patient accuracy, and per-lesion PPV were calculated for each image set. A total of 72 HCCs were present in 33 patients at explant (mean size, 1.5 cm [range, 0.3-6.2 cm]). Per-patient sensitivity and NPV of CE-set were significantly higher than those of DW-set when using pooled data between observers (P = 0.02 and 0.03, respectively), whereas specificity, PPV, and accuracy were equivalent. Per-lesion sensitivity was significantly higher for CE-set versus DW-set (59.0% versus 43.8%; P = 0.008, pooled data from two observers). When stratified by lesion size, the difference was significant only for lesions with a size between 1 and 2 cm (42.0% for DW-set versus 74.0% for CE-set; P = 0.001). The addition of DWI to CET1WI improved sensitivity for the more experienced observer.

CONCLUSION

DWI is outperformed by CET1WI for detection of HCC, but represents a reasonable alternative to CET1WI for detection of HCC with a size above 2 cm. The addition of DWI to CET1WI slightly increases the detection rate.

Oncogenic Kras-induced GM-CSF production promotes the development of pancreatic neoplasia

Stromal responses elicited by early stage neoplastic lesions can promote tumor growth. However, the molecular mechanisms that underlie the early recruitment of stromal cells to sites of neoplasia remain poorly understood. Here, we demonstrate an oncogenic Kras(G12D)-dependent upregulation of GM-CSF in mouse pancreatic ductal epithelial cells (PDECs). An enhanced GM-CSF production is also observed in human PanIN lesions. Kras(G12D)-dependent production of GM-CSF in vivo is required for the recruitment of Gr1(+)CD11b(+) myeloid cells. The suppression of GM-CSF production inhibits the in vivo growth of Kras(G12D)-PDECs, and, consistent with the role of GM-CSF in Gr1(+)CD11b(+) mobilization, this effect is mediated by CD8(+) T cells. These results identify a pathway that links oncogenic activation to the evasion of antitumor immunity.

Leiomyosarcoma of the splenic vein

Leiomyosarcomas are smooth muscle-derived tumors generally found intra-abdominally in the retoperitoneum, mesentery, or omentum. Only approximately 5% of these tumors originate from vessel wall smooth muscle. Those derived from the splenic vein are exceedingly rare, with only one previously published case in the literature. We present a second case of leiomyosarcoma of the splenic vein in a 58-year-old woman with 2 months of epigastric pain. A distal pancreatectomy was performed to include the tumor found centered in the splenic vein at the splenic and portal vein confluence and growing into the pancreas in the body on the posterior aspect. A saphenous vein patch was used for reconstruction.

Adult polyglucosan body disease: a rare presentation with chronic liver disease and ground-glass hepatocellular inclusions

Liver involvement in genetic and metabolic disorders may result in intrahepatic accumulation of specific precursors or byproducts, which have distinctive features on light microscopy. The "polyglucosan disorders" are diseases in which polyglucosan (abnormal glycogen with decreased branching) is formed and deposited in various tissues because of decreased or absent glycogen branching enzyme activity. These disorders include Lafora disease (myoclonus epilepsy) and type IV glycogen storage disease. Polyglucosan deposits in both conditions result in ground-glass hepatocellular inclusions resembling those seen in chronic hepatitis B virus infection. In the present report, we describe a case of the rare, adulthood form of glycogen branching enzyme deficiency, adult polyglucosan body disease (APBD), in which abnormal serum liver tests prompted a liver biopsy. The pathologic findings of periportal ground-glass hepatocellular inclusions, mild chronic portal inflammation, and periportal fibrosis are not well described in APBD, but resemble the chronic changes that have been reported in Lafora disease. The differential diagnosis of ground-glass hepatocytes and the genetic basis of APBD are discussed.

Imaging appearance of bulk fat within an oncocytic adrenocortical neoplasm, a rare and potentially malignant tumour

Oncocytic adrenocortical neoplasm is a rare adrenal tumour that usually follows a benign clinical course. In some cases, however, these tumours have exhibited malignant behaviour. Here, we present the first published case showing bulk fat within an oncocytic adrenocortical neoplasm on CT and MRI, a finding that mimics fat within an adrenal myelolipoma. The distinction between these entities is important, as the current suggested management of an oncocytic adrenocortical neoplasm is resection with subsequent imaging surveillance.

Diagnosis of liver fibrosis and cirrhosis with diffusion-weighted imaging: value of normalized apparent diffusion coefficient using the spleen as reference organ

OBJECTIVE

The purpose of this study is to compare the diagnostic accuracy of liver apparent diffusion coefficient (ADC) versus normalized liver ADC using the spleen as a reference organ for the diagnosis of liver fibrosis and cirrhosis.

MATERIALS AND METHODS

Fifty-six patients, 34 with liver disease and 22 control subjects, were assessed with breath-hold single-shot echo-planar diffusion-weighted imaging using b values of 0, 50, and 500 s/mm(2). Liver ADC and normalized liver ADC (defined as the ratio of liver ADC to spleen ADC) were compared between patients stratified by fibrosis stage. Receiver operating characteristic (ROC) analysis was used to determine the performance of ADC and normalized liver ADC for prediction of liver fibrosis and cirrhosis. Reproducibility was assessed by measuring coefficient of variation (n = 7).

RESULTS

Liver ADC failed to distinguish individual stages of fibrosis, except between stages 0 and 4. There were significant differences in normalized liver ADC between control livers and intermediate stages of fibrosis (stages 2-3) and cirrhosis (stage 4) and between stages 1 and 4, and there was a trend toward significance between stages 0 and 1 (p = 0.051) and stages 1 and 3 (p = 0.06). ROC analysis showed that normalized liver ADC was superior to liver ADC for detection of stage > or = 2 (area under the ROC curve, 0.864 vs 0.655; p = 0.013) and stage > or =3 (0.805 vs 0.689; p = 0.015), without a difference for diagnosing cirrhosis (0.935 vs 0.720; p = 0.185). Normalized liver ADC had higher reproducibility than ADC (mean coefficient of variation, 3.5% vs 12.6%).

CONCLUSION

Our results suggest that normalizing liver ADC with spleen ADC improves diagnostic accuracy for detection of liver fibrosis and cirrhosis when using breath-hold diffusion-weighted imaging, with better reproducibility.

Levels of elevated circulating endothelial cell decline after tumor resection in patients with pancreatic ductal adenocarcinoma

AIM

To evaluate circulating endothelial lineage cells (ELCs) as biomarkers of tumor neovascularization in patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

ELCs were isolated from the peripheral blood of patients with PDAC (n=14) or controls (n=17) before and after tumor resection/surgery and quantified using flow cytometry. Vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) were detected in tumor using immunohistochemistry and in plasma using an ELISA technique.

RESULTS

Circulating ELC levels were increased in patients with PDAC compared to controls. After PDAC resection, ELC levels declined. ELC level increases were associated with cancer recurrence. VEGF and PlGF were identified in cancer cells and exocrine pancreas cells. Only PlGF was detected in tumor-associated inflammatory cells. Plasma levels of PlGF were higher in patients with PDAC compared to controls.

CONCLUSION

Circulating ELCs are a potential biomarker of PDAC neovascularization, and PlGF may be an important target in treatment of PDAC.

Differentiating pancreatic cystic neoplasms from pancreatic pseudocysts at MR imaging: value of perceived internal debris

PURPOSE

To retrospectively evaluate the sensitivity and specificity of several morphologic findings that may be seen with cystic pancreatic lesions, in the diagnosis of pseudocyst at magnetic resonance (MR) imaging.

MATERIALS AND METHODS

This study was institutional review board approved and HIPAA compliant. From January 1, 2005, to December 31, 2007, electronic radiology and pathology databases were searched to identify patients with pancreatic cystic neoplasms or pseudocysts who underwent pancreatic MR imaging. Twenty-two patients with cystic pancreatic neoplasms that were confirmed at surgical resection (n = 12) or endoscopic ultrasonography (US) with cystic fluid analysis (n = 10) were identified. Of 20 patients with pancreatic pseudocysts, seven had pseudocysts that were identified at pathologic resection and 13 had a clinical history of pancreatitis, with initial computed tomography (CT) revealing no pancreatic cyst and subsequent follow-up MR imaging depicting cystic lesions. Two abdominal radiologists independently and randomly evaluated each case for presence or absence of septa and internal dependent debris and for external cyst morphology on axial and coronal T2-weighted images and three-dimensional gradient-echo T1-weighted images obtained before and after intravenous contrast agent administration. Logistic regression for correlated data was used to assess the usefulness of internal debris, external morphology, and septa for differentiating cystic neoplasms from pseudocysts.

RESULTS

The readers' assessments of the presence or absence of cystic debris were concordant for 40 (95%) of the 42 patients, with a kappa coefficient of 0.889, which indicated nearly perfect agreement. Thirteen (93%) of 14 lesions found to have debris by either or both readers were pseudocysts, and only one (4%) of the 22 cystic neoplasms had debris. Both readers were more likely to identify septa within cystic neoplasms than within pseudocysts; however, the difference was not significant for either reader. The readers were more likely to observe microlobulated morphology in cystic neoplasms than in pseudocysts, with the difference between these lesion types, in terms of prevalence of microlobulated morphology, exhibiting a trend toward-but not reaching-statistical significance (P = .0627).

CONCLUSION

Presence of internal dependent debris appears to be a highly specific MR finding for the diagnosis of pancreatic pseudocyst.

Nonfunctioning Pancreatic Endocrine Neoplasm Presenting as Asymptomatic, Isolated Pancreatic Duct Stricture: A Case Report and Review of the Literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

Nonfunctioning pancreatic endocrine neoplasm presenting as asymptomatic, isolated pancreatic duct stricture: a case report and review of the literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

Intrahepatic portal cavernoma as an indication for liver transplantation

Cavernous transformation of the portal vein (portal cavernoma) consists of a periportal or/and intrahepatic venous collateral network, developed as a result of acute or long-standing portal vein thrombosis. Better control of hemorrhagic and thrombotic complications in the patients with portal cavernoma substantially improves their life span and the clinical outcome. However, biliary complications that occur in the late stages of this disease have been recently recognized as challenging management issues because they recur and are difficult to treat. Because of the relatively small number of the patients with cholangiopathy due to portal cavernoma, there is no current standardized treatment approach. We report the case of a predominantly intrahepatic portal cavernoma occurring in a patient with chronic idiopathic portal vein thrombosis, which led to severe cholangiopathy that mimicked primary sclerosing cholangitis and cholangiocarcinoma, was unresponsive to endoscopic stent placement, and finally required liver transplantation.