Endothelial cells help in the diagnosis of primary versus metastatic carcinoma of the liver in fine needle aspirates. An immunofluorescence study with vimentin and endothelial cell-specific antibodies

Fine needle aspirates of 5 primary hepatocellular carcinomas and 24 carcinomas metastatic to the liver were studied using vimentin and endothelial cell-specific monoclonal antibodies. Numerous endothelial cells dispersed and in bundles overlying clumps of tumor cells were positively stained by both antibodies in smears of primary hepatocellular carcinomas while such cells were rare or absent in metastatic carcinomas, with the exception of clear cell carcinoma of the kidney. It is concluded that endothelial cells, if present in large numbers in fine needle aspirates of a hepatic carcinoma and arranged in bundles that envelope the clumps of tumor cells, can (1) suggest the presence of a primary hepatocarcinoma and (2) narrow the differential diagnosis with the most common metastatic cancers to renal cell carcinoma.