NEOANGIOGENESIS AND SINUSOIDAL CAPILLARIZATION IN DYSPLASTIC NODULES OF THE LIVER

The blood supply of hepatocellular carcinoma (HCC) is primarily arteri al. Recent studies reported differences of vascular, especially arteri al, supply among low-and high-grade dysplastic nodules and HCC. We ass essed arterialization using monoclonal antibody specific for smooth mu scle actin as well as simultaneous changes in sinusoidal capillarizati on in cirrhotic nodules, dysplastic nodules, and HCC. We immunohistoch emically stained 56 cirrhotic nodules, 20 low-grade dysplastic nodules , 27 high-grade dysplastic nodules, and 20 HCCs for alpha smooth muscl e actin (to identify unpaired arteries (i.e., arteries not accompanied by bile ducts) and CD34 (indicating sinusoidal capillarization). Dist ribution and number of unpaired arteries and distribution of sinusoida l capillarization were graded semiquantitatively. Unpaired arteries we re rare in cirrhotic nodules, significantly more common in dysplastic nodules of both types (p < 0.00001), and most common in HCC. Sinusoida l capillarization was least common in cirrhotic nodules, significantly more common in dysplastic nodules (p < 0.0035, and most common in HCC . No topographic relationship between unpaired arteries and sinusoidal capillarization was identified. These findings showed that (1) distri butions of sinusoidal capillarization and unpaired arteries in dysplas tic nodules are intermediate between those in cirrhotic nodules and HC C, supporting dysplastic nodules as premalignant lesions; (2) unpaired arteries are histologically useful for distinguishing dysplastic nodu les from large cirrhotic nodules; and (3) areas of sinusoidal capillar ization within dysplastic nodules are unrelated to location of arteria lization.