Diagnostic Considerations of Nodules in the Cirrhotic Liver: A Case-Based Perspective

Keratin 19 epithelial patterns in cirrhotic stroma parallel hepatocarcinogenesis

Cirrhotic septa harbor vessels and inflammatory, fibrogenic, and ductular epithelial cells, collectively referred to as the ductular reaction (DR). Lack of the DR in the stromal compartment around hepatocellular carcinoma (HCC) has been documented; however, the relationship of epithelial keratin 19 (K19) structures to progression of intralesional carcinogenesis has not been explored. K19 immunoreactivity in the stromal compartment around 176 nodules in cirrhotic explants was examined. Quantitative differences (P < 0.0001) were manifested in three distinct histologically identifiable patterns: "complex" around cirrhotic nodules (CN), "attenuated" around dysplastic nodules (DN), and "absent" around HCC. Markers of necrosis or apoptosis could not explain the perinodular K19 epithelial loss; however, multicolor immunolabeling for K19, vimentin, E-Cadherin, SNAIL, and fibroblast-specific protein 1 (FSP-1) demonstrated discrepancies in immunophenotype and cytomorphologic features. Variability of cellular features was accompanied by an overall decrease in epithelial markers and significantly increased fractions of SNAIL- and FSP-1-positive cells in the DR around DN when compared with CN (P < 0.0001). Immunolabeling of transforming growth factor-β signaling components (TGFβR1, SMAD3, and pSMAD2/3) demonstrated increased percentages of pSMAD2/3 around DN when compared with CN (P < 0.0001). These findings collectively suggest marked alterations in cellular identity as an underlying mechanism for the reproducible extralesional K19 pattern that parallels progressive stages of intranodular hepatocarcinogenesis. Paracrine signaling is proposed as a link that emphasizes the importance of the epithelial-stromal compartment in malignant progression of HCC in cirrhosis.

Liver precancerous lesions and hepatocellular carcinoma: the histology report

The current ability to increase the survival of patients with hepatocellular carcinoma (HCC) relies upon the surveillance of cirrhotic patients. Surveillance allows HCC precursors (dysplastic nodules) and malignant tumors to be recognized at an earlier stage making cure possible. Radiology plays a major role in HCC diagnosis because HCC is characterized by neoarterial vascularisation with a typical imaging pattern. Current international guidelines have restricted the use of the liver biopsy to the characterization of hepatocellular nodules which remain diagnostically equivocal after imaging. Thus pathologists are today facing very challenging and often well differentiated lesions, leading to difficulties in distinguishing high grade dysplasia and well differentiated HCC. In this scenario novel concepts obtained through international consensus have been proposed with emphasis on HCC of small size (up to 2 cm) which includes 2 distinct types, the early and progressed HCC. In this paper we will report the main histopathological criteria of a biopsy which allow the differentiation of HCC precursors (dysplastic nodules) from well differentiated HCC with attention to the role and weight of both classical histopathological criteria and novel immunocytochemical markers. The second part of the paper is devoted to the histopathology report of HCC on surgical specimens including explanted livers and on the differential diagnosis between HCC and liver metastasis.