Hepatoid carcinoma (HC) encompasses epithelial extrahepatic tumors exhibiting features of hepatocellular carcinoma (HCC) both by morphology and immunohistochemistry. Distinguishing metastatic HCC from HC may be challenging, particularly when limited material, such as a cytologic specimen, is available. HC from prostatic origin is unusual and has only rarely been characterized by cytology. Herein we present an 86-year-old male with history of castration-resistant prostate cancer developing a left adrenal gland nodule. Fine needle aspiration revealed a poorly differentiated malignant neoplasm diagnosed as metastatic hepatoid prostatic adenocarcinoma based on immunohistochemistry (positive for HepPar1, AFP, NKX3.1, PSMA, and Racemase; and negative for CK7, CK20, cytokeratin 34betaE12, p63, and Arg-1). Because prostatic carcinoma with hepatoid features is rare, and the patient had failed standard therapy, next generation sequencing was performed in an attempt to identify druggable molecular targets. Well-known prostate carcinoma-related alterations were found in three genes (CDK12, AR, and SPOP). In addition, three variants of uncertain significance (DDR2 R128C, SRC P428L, and HNRNPU K574Sfs*32) were identified, which to the best of our knowledge have not been previously reported. Our results support the power of an immunohistochemistry panel including Arg-1 and HepPar1 when HC is suspected, and highlight the value of cytology for comprehensive diagnostic evaluation.

中文翻译：

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伴有肾上腺转移和新基因改变的肝样前列腺癌

肝样癌 (HC) 包括上皮性肝外肿瘤，通过形态学和免疫组织化学表现出肝细胞癌 (HCC) 的特征。将转移性 HCC 与 HC 区分开来可能具有挑战性，尤其是在可获得有限材料（例如细胞学标本）时。来自前列腺的 HC 是不常见的，很少有细胞学特征。在这里，我们介绍了一名 86 岁男性，他有去势抵抗性前列腺癌病史，发展为左肾上腺结节。细针穿刺显示低分化恶性肿瘤，免疫组化诊断为转移性肝样前列腺腺癌（HepPar1、AFP、NKX3.1、PSMA 和消旋酶阳性；CK7、CK20、细胞角蛋白 34betaE12、p63 和 Arg-1 阴性）。由于具有肝样特征的前列腺癌很少见，并且患者的标准治疗失败，因此进行了下一代测序以试图识别可药物分子靶标。在三个基因（CDK12、AR 和 SPOP）中发现了众所周知的前列腺癌相关改变。此外，还确定了三种意义不确定的变体（DDR2 R128C、SRC P428L 和 HNRNPU K574Sfs*32），据我们所知，这些变体以前没有被报道过。我们的结果支持包括 Arg-1 和 HepPar1 在内的免疫组化组在怀疑 HC 时的作用，并强调了细胞学在综合诊断评估中的价值。在三个基因（CDK12、AR 和 SPOP）中发现了众所周知的前列腺癌相关改变。此外，还确定了三种意义不确定的变体（DDR2 R128C、SRC P428L 和 HNRNPU K574Sfs*32），据我们所知，这些变体以前没有被报道过。我们的结果支持包括 Arg-1 和 HepPar1 在内的免疫组化组在怀疑 HC 时的作用，并强调了细胞学在综合诊断评估中的价值。在三个基因（CDK12、AR 和 SPOP）中发现了众所周知的前列腺癌相关改变。此外，还确定了三种意义不确定的变体（DDR2 R128C、SRC P428L 和 HNRNPU K574Sfs*32），据我们所知，这些变体以前没有被报道过。我们的结果支持包括 Arg-1 和 HepPar1 在内的免疫组化组在怀疑 HC 时的作用，并强调了细胞学在综合诊断评估中的价值。