ANALYTICAL HISTOPATHOLOGICAL DIAGNOSIS OF SMALL HEPATOCELLULAR NODULES IN CHRONIC LIVER-DISEASES

Due to the recent progress in radiology and increased clinical and pat hological interest, small hepatocellular nodules about 1 cm in size ar e frequently being detected in patients with chronic liver disease, pa rticularly liver cirrhosis. Two new types of small hepatocellular nodu les are now known: low-grade hepatocellular carcinomas (HCC) and dyspl astic nodules, in addition to the previously known HCC (classical) and regenerative nodules. Ultrasound-guided needle biopsies from these no dules are routinely used for the differential diagnosis. For compariso n, a simultaneous needle biopsy from the liver remote from the nodule is strongly recommended. Low-grade HCC, which are different from class ical HCC in their morphological atypia and also biological behaviors, show local invasion into the portal tracts and surrounding hepatic par enchyma, but not intrahepatic or extrahepatic metastasis. Dysplastic n odules show mild cellular and structural atypia, a finding which is no t sufficient for making a diagnosis of malignancy. An increased nuclea r/cytoplasmic (NIC) ratio and nuclear crowding, small cell-dysplasia, increased cytoplasmic staining, clear cell change, pseudogland formati on, and fatty change of hepatocytes are variably seen in these nodules . Nuclear changes, local invasion to the portal tract and surrounding liver, and loss of the reticulum fibers along the hepatocytes are usef ul markers favoring low-grade HCC rather than dysplastic nodules. Thes e low-grade HCC and dysplastic nodules should also be distinguished fr om classical HCC as well as large-sized regenerative nodules. A compar ative analysis of the histological findings observed in individual nod ules is a reasonable approach to differential diagnosis at present. Th e recognition and analysis of these two new hepatocellular nodules may augur a new horizon in the study of hepatocellular neoplasm.