Utility of polyclonal and monoclonal antibodies against carcinoembryonic antigen in hepatic fine‐needle aspirates

To assess the usefulness of polyclonal and monoclonal antibodies against carcinoembryonic antigen (CEA) in the differential diagnosis of hepatocellular carcinoma (HCC) vs. metastatic adenocarcinoma (MA), we studied 25 cases of fine‐needle aspirates (FNA) of hepatic lesions. The material consisted of 9 primary HCCs, 8 MAs, and 8 benign hepatic aspirates. For immunostaining, the avidin‐biotin complex technique was performed on paraffin sections of cell blocks, using a standardized automatic immunostainer. Specific bile canalicular immunostaining with polyclonal CEA (pCEA) antibody was present in five of eight (5/8) benign hepatic aspirates and eight of nine (8/9) HCCs. Diffuse cytoplasmic immunostaining with pCEA antibody was present in four of eight (4/8) MAs. None of the aspirates showed any positive immunostaining with monoclonal CEA (mCEA) antibody. We conclude that: (1) pCEA antibody is useful in the evaluation of hepatic FNAs. Diffuse cytoplasmic staining is seen in MAs, whereas canalicular immunostaining pattern is an indication of benign or malignant hepatocytes. (2) Paraffin‐embedded cell blocks made from hepatic aspirate material are suitable for immunostaining with polyclonal CEA antibody. (3) mCEA antibody has no value in the diagnosis of HCC. Diagn Cytopathol 1994; 11:358–362. © 1994 Wiley‐Liss, Inc.