Recent developments in liver pathology

Collagen deposition within brain metastases is associated with leptomeningeal failure after cavity-directed radiosurgery

Background

Leptomeningeal failure (LMF) represents a devastating progression of disease following resection of brain metastases (BrM). We sought to identify a biomarker at time of BrM resection that predicts for LMF using mass spectrometry-based proteomic analysis of resected BrM and to translate this finding with histochemical assays.

Methods

We retrospectively reviewed 39 patients with proteomic data available from resected BrM. We performed an unsupervised analysis with false discovery rate adjustment (FDR) to compare proteomic signature of BrM from patients that developed LMF versus those that did not. Based on proteomic analysis, we applied trichrome stain to a total of 55 patients who specifically underwent resection and adjuvant radiosurgery. We used competing risks regression to assess predictors of LMF.

Results

Of 39 patients with proteomic data, FDR revealed type I collagen-alpha-1 (COL1A1, P = .045) was associated with LMF. The degree of trichrome stain in each block correlated with COL1A1 expression (β = 1.849, P = .001). In a cohort of 55 patients, a higher degree of trichrome staining was associated with an increased hazard of LMF in resected BrM (Hazard Ratio 1.58, 95% CI 1.11-2.26, P = .01).

Conclusion

The degree of trichrome staining correlated with COL1A1 and portended a higher risk of LMF in patients with resected brain metastases treated with adjuvant radiosurgery. Collagen deposition and degree of fibrosis may be able to serve as a biomarker for LMF.

Expression of Markers of Hepatocellular Differentiation in Pancreatic Acinar Cell Neoplasms: A Potential Diagnostic Pitfall

OBJECTIVES

Pancreatic acinar cell carcinoma (ACC) is a rare tumor that frequently metastasizes to the liver and may present a diagnostic challenge due to its morphologic similarity to hepatocellular carcinoma. We investigated α-fetoprotein (AFP), hepatocyte paraffin antigen 1 (HepPar 1), glypican 3, arginase 1, and albumin messenger RNA (mRNA) in situ hybridization (ISH) in pancreatic neoplasms with ACC differentiation to assess their diagnostic value.

METHODS

AFP, HepPar 1, glypican 3, and arginase 1 immunohistochemical staining was performed on 28 ACCs using a tissue microarray. Albumin mRNA ISH was performed on full-faced sections.

RESULTS

Fifteen tumors were positive for at least one marker. Glypican 3 was positive in seven of 28, AFP in five 28, and albumin mRNA ISH in five of 20. None expressed arginase 1.

CONCLUSIONS

Hepatocellular differentiation markers, including albumin mRNA ISH, may be positive in ACC, but arginase 1 appears to be uniformly negative. Thus, its use may improve the accuracy in distinguishing these neoplasms from hepatocellular carcinoma. If ACC diagnosis is considered, acinar differentiation can be reliably demonstrated by trypsin/chymotrypsin.

Spatio-temporal quantitative thermography of pre-focal interactions between high intensity focused ultrasound and the rib cage

OBJECTIVE

The aim of this paper is to quantitatively investigate the thermal effects generated by the pre-focal interactions of a HIFU beam with a rib cage, in the context of minimally invasive transcostal therapy of liver malignancies.

MATERIALS AND METHODS

HIFU sonications were produced by a phased-array MR-compatible transducer on Turkey muscle placed on a sheep thoracic cage specimen. The thoracic wall was positioned in the pre-focal zone 3.5 to 6.5 cm below the focus. Thermal monitoring was simultaneously performed using fluoroptic sensors inserted into the medullar cavity of the ribs and high resolution MR-thermometry (voxel: 1 × 1 × 5 mm3, four multi-planar slices).

RESULTS

MR-thermometry data indicated nearly isotropic distribution of the thermal energy at the ribs' surface. The temperature elevation at the focus was comparable with the pericostal temperature elevation around unprotected ribs, while being systematically inferior, by more than a factor of four on average, to the intra-medullar values. The spatial profiles of the pericostal and intra-medullar thermal build-up measurements could be smoothly connected using a Gaussian function. The dynamics of the post-sonication thermal relaxation as determined by fluoroptic measurements was demonstrated to be theoretically coherent with the experimental observations.

CONCLUSION

The experimental findings motivate further efforts for the transfer towards clinical routine of effective rib-sparing strategies for hepatic HIFU.

Branched chain in situ hybridization for albumin as a marker of hepatocellular differentiation: evaluation of manual and automated in situ hybridization platforms

Albumin, widely recognized as a highly sensitive and specific marker of hepatocellular carcinoma (HCC), is currently unavailable in the diagnostic laboratory because of the lack of a robust platform. In a prior study we detected albumin mRNA in the majority of intrahepatic cholangiocarcinomas using a novel branched chain RNA in situ hybridization (ISH) platform. We now explore the utility of albumin ISH as a marker of hepatocellular differentiation in HCCs, and compare its sensitivity with Hep Par 1 and Arginase-1. We evaluated 93 HCCs and its mimics including neuroendocrine tumors of the gastrointestinal tract (n=31), neuroendocrine tumors of the pancreas (n=163), melanoma (n=15), and gallbladder carcinoma (n=34). We performed ISH for albumin and immunohistochemistry for Hep Par 1 and Arginase-1. Five previously uncharacterized hepatic neoplasms from our files were also evaluated. Immunohistochemistry for Arginase-1 was performed on 59 intrahepatic cholangiocarcinomas. In addition, 43 HCCs evaluated on the manual platform were also examined on the automated instrument. Fifty-five percent of HCCs were moderately differentiated and 39% poorly differentiated. The sensitivity of ISH for albumin was 99%, with 92 of 93 HCCs staining positive for albumin. In contrast to ISH, the sensitivity of immunohistochemistry for Hep Par 1 and Arginase-1 was 84% and 83%, respectively. The sensitivity of albumin for poorly differentiated HCCs was 99%, whereas that for Arginase-1 and Hep Par 1 was 71% and 64%, respectively. Ninety-seven percent of the HCCs showed albumin positivity in >50% of tumor cells using the ISH platform, as compared with 76% and 70% for Hep Par 1 and Arginase-1 immunohistochemistry, respectively. Three of the 5 previously uncharacterized neoplasms were positive for albumin ISH. Automated albumin ISH platform performed equivalently to the manual format, with albumin reactivity in >50% of tumor cells in all 43 cases that were tested on both platforms. All non-HCCs were negative for albumin. All 59 intrahepatic cholangiocarcinomas were negative for Arginase-1. In conclusion, branched chain ISH performed on manual and automated mode is a robust assay for detecting albumin with sensitivity for poorly differentiated HCCs superior to Arginase-1 and Hep Par 1. When interpreted in conjunction with Arginase-1, albumin ISH offers a high level of sensitivity and specificity.

Thermal fixation of swine liver tissue after magnetic resonance-guided high-intensity focused ultrasound ablation

The aim of this study was to investigate experimental conditions for efficient and controlled in vivo liver tissue ablation by magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU) in a swine model, with the ultimate goal of improving clinical treatment outcome. Histological changes were examined both acutely (four animals) and 1 wk after treatment (five animals). Effects of acoustic power and multiple sonication cycles were investigated. There was good correlation between target size and observed ablation size by thermal dose calculation, post-procedural MR imaging and histopathology, when temperature at the focal point was kept below 90°C. Structural histopathology investigations revealed tissue thermal fixation in ablated regions. In the presence of cavitation, mechanical tissue destruction occurred, resulting in an ablation larger than the target. Complete extra-corporeal MR-guided HIFU ablation in the liver is feasible using high acoustic power. Nearby large vessels were preserved, which makes MR-guided HIFU promising for the ablation of liver tumors adjacent to large veins.

Investigation and management of hepatic incidentalomas

With the widespread use of medical imaging has come the detection of incidental liver lesions that are, by and large, asymptomatic prior to their discovery. These lesions may become a source of anxiety and often require further investigation to reassure the patient of their usually benign nature. Use of contemporary hepatobiliary imaging and simple laboratory tests often allow a definite diagnosis to be made without resorting to exhaustive investigation or inappropriate surgery. The goal of this paper is to review the clinical features and imaging characteristics of common and important liver incidentalomas, their natural course, complications, and indications for surgical or other intervention.

Can a decision-making model be justified in the management of hepatocellular adenoma?

During recent years, there was a great development in the area of hepatocellular adenomas (HCA), especially regarding the pathological subtype classification, radiological imaging and management during pregnancy. This review discusses the current knowledge about diagnosis and treatment modalities of HCA and proposes a decision-making model for HCA. A Medline search of studies relevant to epidemiology, histopathology, complications, imaging and management of HCA lesions was undertaken. References from identified articles were hand-searched for further relevant articles.

Tumoral and angiogenesis factors in hepatocellular carcinoma after locoregional therapy

Locoregional therapy (LRT) is used as a bridge to orthotopic liver transplant (OLT) for hepatocellular carcinoma (HCC) patients. Liver explants in OLT patients with HCC were studied regarding both tumor stage, histology, and immunohistochemical staining for cytokeratin (CK)7, CK19, P53, Ki-67, and vascular endothelial growth factor (VEGF). Patients receiving no LRT (control) (n=30) were compared with LRT treatment groups with conventional transarterial chemoembolization (cTACE) (n=25) or drug-eluting bead transarterial chemoembolization (DEB TACE) (n=17). Tumor stage and histology were similar between treatment and control groups. The mean percent necrosis was significantly higher for treatment groups versus the control group (p<0.0001 for both groups versus control) and was significantly higher in the cTACE group versus the DEB TACE group. Only the DEB TACE group showed peritumoral CK19 positivity, and tumors were all CK19-negative. Using a threshold of 50% of tumoral cells, tumoral VEGF was significantly different between groups, with the control group having the highest degree of positivity; however, peritumoral VEGF was not significantly different between the groups. The Ki-67 proliferation fraction was higher in the treated groups with a statistically significant difference between the DEB-treated group and those without treatment (p=0.02). There were no statistically significant differences in tumoral or peritumoral CK7 or p53. Percent necrosis and percent Ki-67 positivity were higher with LRT, with a significant difference between groups for percent necrosis, confirming that LRT causes necrosis and suggesting that treatment leads to increased proliferation and decreased tumoral VEGF.

Liver iron overloading in captive muriquis (Brachyteles spp.)

BACKGROUND

Iron accumulation was investigated qualitatively and quantitatively in the liver of 15 captive Brachyteles spp.

METHODS

Hepatic hemosiderosis index (HHI) was determined as the area percentage of the liver parenchyma occupied by hemosiderin and ferritin deposits, through computerized histomorphometric analysis of Prussian blue-stained histologic sections.

RESULTS

All studied animals presented liver hemosiderosis, and HHI ranged from 0.2% to 41.7%. There were no significant differences in HHI between muriqui species or genders, and no correlations were detected among HHI and age, time in captivity or body mass. Iron deposits were accompanied by other hepatic disorders.

CONCLUSIONS

This is the first study addressing the occurrence and consequences of iron overloading in the liver of muriquis. We propose that hemosiderosis may act as a contribute factor for the development of hepatic injuries. Further studies are advised to clarify the role of diet in the pathogenesis of hemosiderosis in these atelids.

Focused ultrasound as a local therapy for liver cancer

Conventional surgical treatments of liver cancer are invasive (including minimally invasive) with a high incidence of new metastasis and poor success, even after multiple resections or ablations. These limitations motivated research into new, less invasive solutions for liver cancer treatment.Focused ultrasound surgery (FUS), or high-intensity focused ultrasound, has been recognized as a noninvasive technology for benign and malignant tumor treatment. Previously, FUS was guided with ultrasound that has limited target definition and monitoring capability of the ablation process. Combining magnetic resonance imaging (MRI) with multiple-element phased-array transducers to create MRI-guided focused ultrasound thermal therapy provides more accurate targeting and real-time temperature monitoring. This treatment is hindered by the ribcage that limits the acoustic windows to the liver and the respiratory motion of the liver. New advances in MRI and transducer design will likely resolve these limitations and make MRI-guided FUS a powerful tool in local liver cancer therapy. This article reviews this technology and advances that can expand its use for cancer treatment in general and liver cancer in particular.