The Utility of Immunohistochemistry in Diagnosing Liver Adenocarcinoma in Patients With Pancreatic Mass

Abstract

Abstract Objectives Biopsies of liver lesions frequently have two goals: confirm malignancy and determine the site of origin. We frequently encounter liver biopsies in patients with pancreatic mass (PM). Given the lack of a specific marker for pancreatic adenocarcinoma, a broad panel of immunohistochemical (IHC) stains is frequently done. In this study, we evaluated the usefulness of IHC staining in the setting of a liver biopsy in the presence of PM. Methods Between 2011 and 2017, 85 cases of liver biopsies or segmental resections with a diagnosis of adenocarcinoma in the presence of PM were retrieved from our archives. Clinical history of other malignancies, any other lesions detected by imaging studies, CA19-9 levels, and reevaluation of the available H&E and IHC slides were performed. Results The patients were divided into four groups: 74.1% with isolated PM on imaging and no previous history of any malignancy, 12.9% with PM on imaging with previous history-proven adenocarcinoma of the pancreas, 7.0% with PM in association with another lesion shown by imaging studies in other organs, and 5 (5.8%) PM on imaging in association with previous history of cancer somewhere else other than pancreas. At least two IHC stains were performed for each case. CK7 was ordered in all the cases and was positive in 100%; CK20 was positive in 35.8%. Interestingly, TTF-1 was positive in only one case, in the absence of discrete lung mass; the patient was treated for pancreatic adenocarcinoma. Conclusion We suggest that in the presence of PM, with liver metastasis of adenocarcinoma morphology on H&E, the metastasis is from the pancreas or upper gastrointestinal primarily and no need for further stains. Although performing IHC is useful sometimes, it should be ordered wisely; this practice will lower costs and result in higher quality care, with more effective use of the lab resources and personnel.