[Histopathological diagnosis of primary liver tumors]

Although modern imaging can predict the diagnosis of the vast majority of liver neoplasms, liver biopsy remains the safest, most accurate and most economical diagnostic gold standard for therapeutic implications. Refined preparation techniques using fine-needle biopsy lead to the correct diagnosis by conventional staining in most cases. Metastases and rare mesenchymal liver tumors that mimic primary hepatocellular tumors morphologically can be distinguished by use of a panel of antibodies in immunohistochemistry. Precursors of hepatocellular carcinoma (HCC) remain difficult to categorize in small biopsy specimens. Differentiation of HCC from regenerative nodules and liver cell adenomas can be achieved by molecular techniques applicable to formalin-fixed and paraffin-embedded tissue (FISH or ISH). The grading and staging of resected malignant liver neoplasms according the pTNM system still have the most important prognostic impact, but screening of changes in the cell cycle by immunohistochemistry and application of molecular techniques may prove to have prognostic value in the near future.