Can CD34 discriminate between benign and malignant hepatocytic lesions in fine-needle aspirates and thin core biopsies?

BACKGROUND. Distinguishing well differentiated hepatocellular carcinoma (HC C) from benign hepatocellular lesions is a well recognized problem in fine- needle aspiration (FNA) cytology. The endothelial cell marker CD34 is negat ive in normal hepatic sinusoids and stains vessels diffusely in HCC. This f eature is useful in distinguishing benign from malignant hepatocytic lesion s in histological specimens, although benign lesions may show focal positiv ity for CD34 confined to periportal and periseptal areas. In this study, we assess the role of CD34 in cell block and thin core biopsy material from b enign and malignant hepatocellular lesions, and compare it with reticulin s taining. METHODS. Cell blocks and thin core biopsies were assessed from 40 cases of HCC and 25 benign hepatocytic lesions. HCCs were scored for nuclear grade. Sections were stained for CD34 antigen and scored semi-quantitatively. Prev iously per formed reticulin stains were reviewed. RESULTS. Thirty three of 40 HCCs (82.5%) showed diffuse positivity for CD34 . The other seven cases showed either focal positivity (four cases), minima l positivity (two cases) or negative staining (one case). These results did not correlate with the nuclear grade of the tumor. Two of 25 benign cases (8%) showed diffuse positivity for CD34, 8 showed focal positivity, 11 show ed minimal positivity, and 4 showed negative staining. All HCCs showed an a bnormal reticulin pattern characterized by expanded trabeculae and islands, or sheets, with decreased or absent reticulin. All of the benign hepatocel lular lesions showed a normal trabecular reticulin pattern. CONCLUSIONS. Diffusely positive CD34 staining is useful to support a diagno sis of well differentiated HCC, but in our study the reticulin stain distin guished more consistently between benign and malignant lesions. Cancer (Can cer Cytopathol) 2000;90:273-8. (C) 2000 American Cancer Society.