Enzymatic cytochemistry, DNA ploidy and AgNOR quantitation in hepatocellular nodules of uncertain malignant potential in liver cirrhosis.

Conventional histological examination of echo-guided biopsy specimens can be inconclusive in small nodular lesions in cirrhotic livers. We investigated the diagnostic potential of cytochemical analysis of dipeptidyl-peptidase IV (DPP IV), of image analysis of nuclear DNA content, and of interphase silver-stained nucleolar organizer regions (AgNORs) in 12 cases of small (13- to 29-mm in diameter) hepatic nodules visualized in cirrhotic patients by ultrasonography. All cases underwent an echo-guided liver biopsy at the time of detection and in none of them were histological signs of malignancy found. Characterization with the above-mentioned techniques was always done at the time of histological examination. These patients underwent a mean (+/- SD) follow-up of 27.0 (+/- 11.2) months after biopsy, with repeated ultrasound (US) examinations. In the seven patients with subsequent neoplastic growth, DPP IV score was altered in five of six; the fraction of mononucleated polyploid cells was altered in six of seven; and the AgNOR quantity exceeded the cutoff value of 4 microns2 in five of five cases. Among the five lesions whose US appearance remained unchanged during the follow-up, only one abnormality (AgNORs) was found in one case. The combined cytochemical analysis of DPP IV, nuclear DNA content, and quantitative evaluation of interphase AgNORs in biopsy samples may contribute to the differential diagnosis of hepatocellular nodules of uncertain type in the cirrhotic liver.