Primary Liver Carcinomas: Challenges, Tools, and Diagnostic Considerations

Course overview

Primary liver carcinomas (PLCs), including hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), are the most common categories of adult primary liver neoplasm with major clinical and surgical implications; however, their diagnosis is fraught with potential pitfalls for the surgical pathologist. This presentation examines the general morphologic features of HCC and iCCA as well as uses and limitations of ancillary stains used to support their diagnosis. A basic approach and discussion of diagnostic challenges is also presented for the common scenario of adenocarcinoma in a liver mass biopsy, as well as for particularly challenging cases of poorly differentiated primary liver carcinomas (PD-PLCs). The potential role for genomic analysis in the categorization of PD-PLCs is discussed, along with insights gained from next generation sequencing of both PD-PLCs and their equally confounding counterpart, combined hepatocellular cholangiocarcinomas. After this presentation, participants will be able to: 1) Describe the general morphologic features and uses/limitations of ancillary stains used to identify HCC 2) Describe the general morphologic features and uses/limitations of ancillary stains used to identify iCCA 3) Acknowledge the role of immunohistochemistry and albumin in situ hybridization (ISH) in the workup of adenocarcinoma in a liver biopsy 4) Observe the challenges in differentiating HCC and iCCA in PD-PLC cases, and the potential role of genomic analysis in evaluating these tumors