Arginase-1 is frequently positive in hepatoid adenocarcinomas.

Hepatoid adenocarcinoma is a rare extrahepatic tumor, which shows morphological and immunohistochemical similarities to hepatocellular carcinoma (HCC). Hence, hepatoid adenocarcinoma can cause diagnostic confusion with HCC. Arginase-1 immunostain has been recently shown to be an excellent marker of normal hepatocytes and is a sensitive and specific marker for HCC. However, the expression of Arginase-1 in hepatoid adenocarcinoma has not been evaluated in detail. Eight cases of hepatoid adenocarcinoma were immunostained with Arginase-1, Hepar-1, Glypican-3, CK7, CK20, CK19, polyclonal carcinoembryonic antigen, ɑ-fetoprotein, CDX2, and TTF-1. Albumin in situ hybridization was performed in 4 cases. All 8 cases were positive for Hepar-1. Arginase-1 was positive in 5 (62.5%) of 8 cases; 2 of these cases showed diffuse staining, while 3 showed patchy staining. Glypican-3, CK7 and ɑ-fetoprotein were each positive in 4 (50%) of 8 cases. CK19 was positive in 3 (37.5%) of 8 cases. polyclonal carcinoembryonic antigen showed canalicular staining in 3 (37.5%) of 8 cases and albumin in situ hybridization was positive in 3 (75%) of 4 cases. CDX2 was positive in 2 (25%) of 8 cases, both arising from the stomach. CK20 was positive in 1 (12.5%) of 8 case while TTF-1 was negative in all cases. Hepatoid adenocarcinoma has a similar immunostaining profile as HCC. Arginase-1 expression is common (62.5%) in hepatoid adenocarcinoma and hence it is not useful in distinguishing HCC from hepatoid adenocarcinoma.

Chandan VS ，Shah SS ，Torbenson MS ，Wu TT ... -  《-》

Hepatoid adenocarcinoma with liver metastasis mimicking hepatocellular carcinoma: an immunohistochemical and molecular study of eight cases.

Terracciano LM ，Glatz K ，Mhawech P ，Vasei M ，Lehmann FS ，Vecchione R ，Tornillo L ... -  《AMERICAN JOURNAL OF SURGICAL PATHOLOGY》

Hepatocyte differentiation markers in adenocarcinoma of the prostate: hepatocyte paraffin 1 but not arginase-1 is specifically expressed in a subset of prostatic adenocarcinoma.

Prostate adenocarcinoma and hepatocellular carcinoma (HCC) are common cancer types. Both may present with bone metastases, and both are known to be CK7/CK20 negative. Thus, diagnosis of less well-differentiated tumors at metastatic sites essentially relies on immunohistochemical confirmation. However, insufficient data exist on the expression status of the main 2 hepatocyte markers hepatocyte paraffin 1 (HepPar-1) and arginase-1 (Arg-1) in prostatic adenocarcinoma. We screened 557 prostate carcinoma cases for expression of these 2 markers using tissue microarrays. Sixty-four of 557 (11.5%) cases showed highly variable expression of HepPar-1 in 1% to 75% of tumor cells with a characteristically strong granular "mitochondrial" pattern. Only 13 cases (2.3%) expressed HepPar-1 in greater than 10% of the tumor cells. No correlation was seen with Gleason grade. On the other hand, 19 (3.4%) of 557 cases showed variable nonspecific cytoplasmic expression of Arg-1 distinct from the specific combined nucleocytoplasmic staining seen in normal liver and in HCC. Specifically, this Arg-1 pattern was seen only using one antibody lot and not another suggesting cross-reactivity. Only a single case showed specific nucleocytoplasmic expression of Arg-1 in the tumor cells. In conclusion, specific granular cytoplasmic staining for HepPar-1 is frequent in prostatic adenocarcinomas (11.5%) but usually focal and limited to less than 5% of tumor cells. This should not be misinterpreted as evidence of HCC, particularly in solid-pattern neoplasms. On the other hand, specific Arg-1 expression is very rare (0.18%), highlighting the value of Arg-1 in distinguishing HepPar-1-positive prostatic carcinoma from HCC at metastatic sites or in cases of liver metastasis from prostate carcinoma.

Giedl J ，Büttner-Herold M ，Wach S ，Wullich B ，Hartmann A ，Agaimy A ... -  《-》

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

Shahid M ，Mubeen A ，Tse J ，Kakar S ，Bateman AC ，Borger D ，Rivera MN ，Ting DT ，Deshpande V ... -  《-》

Hepatoid adenocarcinoma of the lung: report of five cases and review of the literature.

Haninger DM ，Kloecker GH ，Bousamra Ii M ，Nowacki MR ，Slone SP ... -  《-》