Evaluation of the CD34 and CD10 immunostains using a two‐color staining protocol in liver fine‐needle aspiration biopsies

Fine‐needle aspiration (FNA) biopsies of liver masses may need immunohistochemistry to resolve difficult cases. We examined liver FNAs with CD10 and CD34 using a two‐color staining protocol. Fifty‐one cases of hepatocellular carcinoma (HCC) and 23 cases of liver metastases were stained first with CD10 using diaminobenzidine as a chromogen and then with CD34 using Fast Red. All cases were reviewed in a blinded fashion by two of the authors (R.I.Z. and Z.B.). Diagnoses were unblinded and staining patterns evaluated. Forty‐eight of 51 cases of HCC stained for CD34 in a peripheral pattern and no cases of metastases stained for CD34 Seven of 23 cases of metastatic disease stained for CD10 in a diffuse cytoplasmic distribution and 29 of 51 HCCs stained in a canalicular pattern. Overall, the sensitivity of the CD10/CD34 combination was 98% and the specificity was 100% for HCC when appropriate staining patterns were observed. Two‐color immunostaining with CD10 and CD34 may prove useful in distinguishing HCC from metastases. Diagn. Cytopathol. 2005;32:88–91. © 2005 Wiley‐Liss, Inc.