The vascular profile of regenerative and dysplastic nodules of the cirrhotic liver: Implications for diagnosis and classification

We investigated the angiogenic phenotype of regenerative and dysplastic hep atocellular nodules to assess whether these lesions have distinct vascular profiles compared with the adjacent nonneoplastic or malignant liver. Forty -three liver nodules surgically removed from 18 patients were classified in to regenerative and dysplastic categories. Serial sections of each nodule, adjacent cirrhotic liver (16 patients), and associated hepatocellular carci noma (HCC) (6 patients), have been immunostained against CD31 and alpha-smo oth muscle actin (alpha SMA) to detect capillary and muscular vessels. The study included 20 large regenerative nodules (LRNs), 13 low-grade dysplasti c nodules (LGDNs), and 10 high-grade dysplastic nodules (HGDNs). The number of both capillary units and unpaired arteries tvas significantly increased in HGDNs and malignant lesions over LGDNs, regenerative, and cirrhotic nod ules (P < .01), which showed an overlapping vascular profile. In addition, the number of capillary units, but not that of unpaired arteries, was signi ficantly increased in HCC compared with HGDNs (P < .01). These results show that certain angiogenic features segregate HGDNs from other nonmalignant n odules such as LRNs and LGDNs. The former group of lesions is similar to HC C whereas the latter group is undistinguishable from the adjacent cirrhosis as far as their vascular profile is concerned. The adopted investigative a pproach does not support the morphological distinction between LRNs and LGD Ns although it suggests that HGDNs are likely advanced precursors of HCC. A n abnormal number of capillary units and/or unpaired arteries in a nonmalig nant hepatocellular nodule can be diagnostically helpful to identify a prec ancerous lesion.