A Triple Stain of Reticulin, Glypican-3, and Glutamine Synthetase A Useful Aid in the Diagnosis of Liver Lesions

Context.-The correct histologic diagnosis of mass lesions of the liver can be difficult, especially in biopsy samples. Reticulin, glypican-3, and glutamine synthetase are stains that can help distinguish hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia. Objective.-To evaluate the utility of a triple stain of reticulin, glypican-3, and glutamine synthetase in distinguishing hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia. Design.-Whole tissue sections and tissue microarrays were evaluated with a triple stain of reticulin, followed by glutamine synthetase (diaminobenzidine, brown chromogen) and glypican-3 (alkaline phosphatase, red chromogen). The 109 cases evaluated included whole tissue section hepatocellular carcinoma (n = 16), tissue microarray hepatocellular carcinoma (n = 19), whole tissue section hepatic adenoma (n = 15), tissue microarray hepatic adenoma (n = 13), whole tissue section focal nodular hyperplasia (n = 13; 12%), tissue microarray focal nodular hyperplasia (n = 13), as well as nonmalignant liver parenchyma adjacent to hepatocellular carcinoma (n = 20). All cases were scored for reticulin being intact or lost, positive or negative staining for glypican-3, and diffuse, maplike, perivenular, or negative staining for glutamine synthetase. Results.-The combination of intact reticulin with either glypican-3 negativity or negative glutamine synthetase was 92% sensitive and 95% specific in the distinction of tissue microarray hepatic adenoma from hepatocellular carcinoma. For the distinction of tissue microarray focal nodular hyperplasia and hepatic adenoma, maplike glutamine synthetase was most useful and was 85% sensitive and 100% specific. Conclusions.-The triple stain of reticulin, glypican-3, and glutamine synthetase is useful in the differentiation of hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia on biopsy specimens. Furthermore, this triple stain is advantageous to single stains and can help when aberrant staining patterns are observed.