Review ArticlesDiagnosis of Well-differentiated Hepatocellular Lesions: Role of Immunohistochemistry and Other Ancillary TechniquesShafizadeh, Nafis MD*; Kakar, Sanjay MD†Author Information *Department of Pathology, Southern California Permanente Medical Group, Woodland Hills Medical Center, Woodland Hills †Department of Pathology, University of California, San Francisco, San Francisco VA Medical Center, San Francisco, CA The authors have no funding or conflicts of interest to disclose. Reprints: Sanjay Kakar, MD, Department of Pathology, 113B, UCSF and VA Medical Center, 4150 Clement Street, San Francisco, CA 94121 (e-mail: email@example.com). Advances In Anatomic Pathology: November 2011 - Volume 18 - Issue 6 - p 438-445 doi: 10.1097/PAP.0b013e318234abb4 Buy Metrics Abstract There is considerable overlap in morphologic features in well-differentiated hepatocellular lesions necessitating the use of immunohistochemistry and other techniques for diagnosis. Map-like pattern with glutamine synthetase in focal nodular hyperplasia and cytoplasmic staining with serum amyloid associated protein in inflammatory hepatocellular adenoma (HA) are useful for this distinction. The distinction of well-differentiated hepatocellular carcinoma (HCC) and HA in noncirrhotic liver is facilitated by demonstrating glypican-3 and cytogenetic changes like gains of chromosomes 1 and 8. Nuclear staining with β-catenin and/or diffuse staining with glutamine synthetase strongly favors well-differentiated HCC or HA with high risk for HCC. In a cirrhotic liver, separation of early HCC from high-grade dysplastic nodule requires identification of stromal invasion, which can be highlighted by absence of keratin 7-positive ductular reaction. Combined use of heat shock protein 70, glutamine synthetase, and glypican-3 can be useful as positivity for 2 or more of these markers has shown high specificity for HCC in early studies. © 2011 Lippincott Williams & Wilkins, Inc.