Search

The data used for the World Health Organization classification of hepatocellular adenoma (HCA) is largely based on cases from tertiary level centers in Europe. This study examines the distribution of HCA subtypes in a large community population and determines the impact of immunohistochemistry (IHC) on reclassification, diagnosis, and management. All cases diagnosed as HCA in a large community hospital network from 2000 to 2010 were reviewed. The following immunohistochemical stains were evaluated in cases where paraffin-embedded tissue was available (n = 35): β-catenin, glutamine synthetase, serum amyloid A, C-reactive protein, liver fatty acid binding protein. Twenty-eight of 35 cases were confirmed to be HCA, 5 cases were reclassified as well-differentiated hepatocellular carcinoma, and 2 cases were reclassified as focal nodular hyperplasia. The HCA cases were further subclassified into hepatocyte nuclear factor 1α inactivated (29%), inflammatory (32%), inflammatory with β-catenin activation (3%), noninflammatory β-catenin activated (0%), and unclassified (36%). Long-term follow-up was available on 33 of 35 cases, and there were no cases of recurrence or distant metastasis. IHC can provide a definite HCA subtype in two-thirds of cases. HCA subtypes in this large community-based population differed from the prior large French studies, in that there were a greater proportion of unclassified adenomas and a virtual absence of β-catenin-activated adenomas. It is likely that most β-catenin-activated hepatocellular tumors show morphologic and reticulin staining abnormalities indicative of well-differentiated hepatocellular carcinoma. IHC for glutamine synthetase and serum amyloid A can identify cases with β-catenin activation and aid in the distinction of inflammatory adenoma and focal nodular hyperplasia., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Hepatoblastoma is the most frequent malignant hepatic tumor in children. Expression of high mobility group AT-hook 2, an architectural nuclear factor and marker for hepatic progenitor cells, has not been studied in detail in hepatocellular neoplasms. Immunohistochemical stains using antibodies against high mobility group AT-hook 2, β-catenin, glypican-3, p53, and Ki-67 were performed in 15 hepatoblastomas, 15 fibrolamellar hepatocellular carcinomas, 34 hepatocellular carcinomas (12, ≤30 years old; 22, >30 years old), and 22 hepatic adenomas. High mobility group AT-hook 2 was expressed in all 15 hepatoblastomas, including all fetal and embryonal components, significantly higher than in 41.7% (5/12) of hepatocellular carcinomas of 30 years or younger (P = .001) and in 9% (2/22) of hepatocellular carcinomas of older than 30 years (P < .001). Aberrant β-catenin expression was detected in 80% (12/15) of hepatoblastomas, 41.6% (5/12) of hepatocellular carcinomas of 30 years or younger, and 18.2% (4/22) of hepatocellular carcinomas of older than 30 years. All 15 fibrolamellar hepatocellular carcinomas and 22 hepatic adenomas were negative for high mobility group AT-hook 2 or β-catenin. High mobility group AT-hook 2 and β-catenin expression correlated positively (P = .017; τ = 0.522) in 34 hepatocellular carcinomas. β-Catenin and glypican-3 exhibited a distinct spatial distribution within hepatoblastomas; glypican-3 was more frequently expressed in fetal components (P = .007), whereas β-catenin tended to be more frequently expressed in embryonal components (P = .062). In conclusion, high mobility group AT-hook 2 is expressed in all hepatoblastomas and could be used as a sensitive marker in their diagnosis. High mobility group AT-hook 2 was also expressed in a subset of hepatocellular carcinomas in association with β-catenin expression; this might represent a subtype of hepatocellular carcinoma with hepatic progenitor cell differentiation., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The histologic distinction between reactive processes and malignant neoplasms and between low-grade and high-grade tumors is not always straightforward and is sometimes extremely challenging. This is especially the case when the diagnostic material is a small biopsy specimen or a cytology specimen with scant cellularity. In addition, suboptimal processing and crush artifact may limit accurate diagnosis. A reliable diagnostic biomarker that preferentially highlights malignant processes and high-grade tumors would be very valuable in segregating these entities from reactive processes and low-grade lesions. Recent extensive studies have shown that an oncoprotein, insulin like-growth factor II messenger RNA binding protein-3, is not only a prognostic biomarker but also a diagnostic molecule. This review focuses on discussing the value of insulin like-growth factor II messenger RNA binding protein-3 in diagnostic pathology, with a focus on utilization of insulin like-growth factor II messenger RNA binding protein-3 in the discrimination of benign effusions from malignant effusions, malignant mesothelioma from mesothelial hyperplasia, carcinoids from high-grade neuroendocrine carcinomas, low-grade dysplasia from high-grade dysplasia, hepatocellular carcinoma from hepatic adenoma, cholangiocarcinoma and metastatic pancreatic ductal carcinoma from benign bile duct lesions, melanoma from nevi, and follicular thyroid carcinoma from follicular adenoma of the thyroid, as well as examining insulin like-growth factor II messenger RNA binding protein-3 expression in lymphomas of germinal center origin., (Copyright © 2011 Elsevier Inc. All rights reserved.)

In our earlier work, we demonstrated that agrin, a multifunctional heparan sulfate proteoglycan, accumulates in hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC). In addition, we proved the utility of agrin immumohistochemistry in discriminating between HCCs and benign parenchymal lesions. Here, we have examined the expression of agrin in metastatic liver carcinomas in comparison with primary liver tumors. Immunohistochemistry for agrin was performed on 25 HCC, 16 intrahepatic CCC, 20 colorectal cancer metastasis (CRCm), and 18 pancreatic ductal carcinoma metastasis (PDCm) samples and evaluated with both quantitative and qualitative methods. Agrin/CD34 double immunofluorescent staining was carried out on snap-frozen sections. Agrin mRNA expression was measured in 11 HCC, 7 CCC, 11 CRCm, and 12 normal liver tissues. Regardless of tumor grade, agrin immunostaining was strong in the microvessels of HCCs. As opposed to HCC, agrin immunostaining was faint or nearly absent from the CD34-positive microvessels of CCC, CRCm, and PDCm; rather, it was detected in the basement membranes surrounding tumor cell pseudoglandules. While agrin was preserved in the basement membranes of Grade III CCCs, it was nearly absent from poorly differentiated metastatic adenocarcinomas. Agrin mRNA levels were the highest in CCC and lower, but still elevated in HCC and CRCm. By qualitative evaluation of agrin immunoreactions, CCC was differentiated from CRCm and PDCm with a sensitivity of 0.81 and a specificity of 0.82. HCCs were unequivocally identified on the basis of microvascular agrin labeling. Thus, agrin immunohistochemistry may facilitate determination of primary versus metastatic origin in problematic liver cancer cases., (Copyright 2010 Elsevier Inc. All rights reserved.)

Cytokeratins 7 and 19 and neuronal cell adhesion molecule (CD56) are differentially expressed in the hepatocytes and biliary epithelium. CD34 is an endothelial marker that is expressed in hepatic sinusoids in conditions associated with altered vascular flow and neoplasms. Distinct staining patterns using these markers have been shown in resected specimens of focal nodular hyperplasia, telangiectatic focal nodular hyperplasia, and hepatic adenoma. The purpose of this study was to examine the diagnostic use of these markers in needle biopsies. Needle biopsies from focal nodular hyperplasia (n = 21), telangiectatic focal nodular hyperplasia (n = 2), and hepatic adenoma (n = 14) were included in the study. These cases represent typical examples of each entity that have been diagnosed on the basis of clinical, imaging, and histologic features. Corresponding resection specimens available in 9 cases were also included in the study for comparison. Immunohistochemical analysis was performed on 4-mum-thick formalin-fixed and paraffin-embedded sections using antibodies against cytokeratin 7, cytokeratin 19, neuronal cell adhesion molecule, and CD34. The staining patterns and intensity for each marker were analyzed in a blinded fashion, and the patterns were recorded as focal nodular hyperplasia-like, hepatic adenoma-like, or indeterminate for each case. Presence of normal tissue was also recorded in each case. The hepatic adenoma-like pattern is characterized by strong cytokeratin 7 positivity in hepatocytes in patches with a gradual decrease in the staining intensity as the cells differentiate toward mature hepatocytes. Hepatic adenomas lack bile ducts and ductules as highlighted by cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule stains. The focal nodular hyperplasia-like pattern is characterized by milder and focal cytokeratin 7 staining of hepatocytes. Cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule show a strong staining of bile ductules in the fibrous septa. Normal liver shows cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule staining of bile ducts, whereas the hepatocytes are generally negative. Of the 21 focal nodular hyperplasia cases, 20 cases (95.2%) showed a focal nodular hyperplasia-like pattern, whereas 13 (92.2%) of 14 hepatic adenoma cases showed a hepatic adenoma-like pattern. Both cases of telangiectatic focal nodular hyperplasia showed a hepatic adenoma-like pattern. CD34 stain showed areas of diffuse endothelial staining in 2 cases of hepatic adenoma, 3 cases of focal nodular hyperplasia, and both cases of telangiectatic focal nodular hyperplasia, whereas the remaining cases showed staining of endothelial cells only in the inflow areas of the sinusoids. A mixed (diffuse and inflow) pattern of CD34 staining was seen in 1 focal nodular hyperplasia, 1 hepatic adenoma, and 2 telangiectatic focal nodular hyperplasia cases. For statistical analysis, the telangiectatic focal nodular hyperplasia were considered as variants of hepatic adenoma. The findings were found to be highly statistically significant (P < .05) for cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule stains. An inflow staining pattern favors a diagnosis of focal nodular hyperplasia; however, overall, CD34 stain was not helpful in differentiating focal nodular hyperplasia and hepatic adenoma. Corresponding resection specimens (hepatic adenoma = 5, focal nodular hyperplasia = 2) showed staining patterns that were identical to the biopsy, whereas resections of the telangiectatic focal nodular hyperplasia cases showed both focal nodular hyperplasia and hepatic adenoma-like areas. Considering that telangiectatic focal nodular hyperplasia is now thought to be a variant of hepatic adenoma, the staining patterns correctly identified all cases, except one case each of focal nodular hyperplasia and hepatic adenoma. In summary, a combination of cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule immunostains performed on needle biopsies of liver shows distinctive patterns similar to that of resection specimen. The stains, especially cytokeratins 7 and 19, are very helpful in distinguishing normal from lesional tissue, as well as hepatic adenoma from focal nodular hyperplasia, and could be diagnostically helpful in challenging cases. Prospective studies to evaluate use of these stains in challenging cases are needed to validate these findings.

Anterior gradient-2 expression is critical in normal embryonic development. Aberrant expression of anterior gradient-2 in adult tissues has been linked to breast, prostate, esophageal, and pancreatic carcinoma. To define the role of anterior gradient-2 in primary hepatocellular neoplasms, we used tissue microarrays and examined protein expression in typical hepatocellular carcinomas (n = 44), fibrolamellar carcinomas (n = 12), and hepatic adenomas (n = 9). In nonneoplastic liver tissues, anterior gradient-2 was expressed in the septal-sized bile ducts and weakly in zone 3 hepatocytes in 11 (18%) of 61 cases. In tumors, anterior gradient-2 was overexpressed by only 1 (2%) of 44 hepatocellular carcinomas. In contrast, 6 (75%) of 8 fibrolamellar and 3 (75%) of 4 metastatic fibrolamellar carcinomas were positive. All 9 hepatic adenomas were negative. Further analysis of mRNA in fibrolamellar carcinomas identified 2 novel splice variants, but expression levels were very low. Sequencing of the anterior gradient-2 gene in fibrolamellar carcinomas identified several polymorphisms (refSNP Ids: rs6842, rs8071, rs1051905) but no mutations. In conclusion, anterior gradient-2 is overexpressed in the majority of fibrolamellar carcinomas but is only rarely overexpressed in hepatocellular carcinomas.

Differentiating focal nodular hyperplasia from hepatic adenoma can be challenging. Cytokeratin 7, neuronal cell adhesion molecule, and cytokeratin 19 are differentially expressed in hepatocytes, biliary epithelium, and possibly hepatic progenitor/stem cells. CD34 is known to have altered expression patterns in the hepatic endothelium in conditions associated with abnormal perfusion and in hepatocellular carcinoma. The purpose of this study was to examine the expression pattern of these markers in focal nodular hyperplasia and hepatic adenoma and assess their diagnostic use. Ten resection specimens each of hepatic adenoma and focal nodular hyperplasia (including a case of telangiectatic focal nodular hyperplasia) were selected for the study. Immunohistochemical analysis was performed using antibodies against cytokeratin 7, cytokeratin 19, neuronal cell adhesion molecule, and CD34 on formalin-fixed, paraffin-embedded sections from each case. The staining patterns and intensity for each marker were analyzed. In hepatic adenoma, the cytokeratin 7 stain revealed strong positivity in hepatocytes in patches, with a gradual decrease in the staining intensity as the cells differentiated towards mature hepatocytes. Although bile ducts were typically absent in hepatic adenoma, occasional ductules could be identified with cytokeratin 7 stain. In focal nodular hyperplasia, cytokeratin 7 showed strong staining of the biliary epithelium within the fibrous septa and staining of the peripheral hepatocytes of most lobules that was focal and weaker than hepatic adenoma. Cytokeratin 19 and neuronal cell adhesion molecule showed patchy and moderate staining in the biliary epithelium of the ductules in focal nodular hyperplasia. While in the hepatic adenoma, cytokeratin 19 showed only rare positivity in occasional cells within ductules, and neuronal cell adhesion molecule marked occasional isolated cells in the lesion. CD34 showed staining of sinusoids in the inflow areas (periportal areas) in both focal nodular hyperplasia and hepatic adenoma. One case of telangiectatic focal nodular hyperplasia revealed both hepatic adenoma-like and focal nodular hyperplasia-like staining patterns. Distinct cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule staining patterns are seen in hepatic adenoma and focal nodular hyperplasia possibly suggest activation of different subsets of hepatic progenitor/stem cell and can be diagnostically useful.