IMMUNOCYTOCHEMICAL STAINING OF FINE-NEEDLE ASPIRATION BIOPSIES OF THE LIVER AS A DIAGNOSTIC-TOOL FOR HEPATOCELLULAR-CARCINOMA

Fine-needle aspiration biopsy (FNAB) under ultrasonographic or computerized tomographic guidance is a useful diagnostic procedure for hepatic neoplasms. However, cytologic criteria alone may not allow for the distinction of hepatocellular carcinomas (HCC) from cholangiocarcinomas (CC) and metastatic adenocarcinomas (MA). In an effort to refine the FNAB diagnosis of hepatic malignancies, a panel of immunocytochemical stains was applied to aspiration specimens from primary and metastatic carcinomas in the liver. Anticytokeratin antibodies with different specificities (Cam 5.2 and AE1) were used in conjunction with antibodies to carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and alpha-1-antitrypsin (AAT). All HCC, CC, and MA were immunoreactive with the antikeratin antibody Cam 5.2. However, only three (15%) HCC were positive with AE1, in contrast to 100% of CC and MA. Antibodies to CEA and AFP were also helpful diagnostic aids, especially for the three HCC that were immunoreactive with AE1. Canalicular staining for CEA was present in 47% of HCC, but in none of the CC or MA. AFP positivity occurred in 45% of HCC, but only one CC and none of the MA. AAT was not a useful marker for HCC due to low sensitivity and specificity. Immunocytochemistry is an effective adjunct to the cytodiagnosis of malignant liver tumors sampled by FNAB.