This issue of Pathology Case Reviews focuses on problem areas in pathology of hepatic tumors, with an emphasis on areas that are commonly encountered in practice, such as evaluation of nodular lesions in cirrhosis, distinction of benign hepatocellular tumors from hepatocellular carcinoma, and fine needle aspiration of liver nodules. Less commonly encountered but often problematic lesions for the surgical pathologist, such as hepatoblastoma and angiomyolipoma are also discussed. Given the rising incidence of cholangiocarcinoma and diagnostic challenges associated with this diagnosis, a timely discussion of the clinicopathologic features, and diagnostic pitfalls of this tumor is included. Finally, an overview of immunohistochemistry in diagnosis of hepatocellular carcinoma provides guidance in selecting an appropriate diagnostic panel of markers for evaluation of liver tumors, both primary and metastatic.
Although many of us do not encounter hepatic resections for tumor on a daily basis, most practicing surgical pathologists are confronted with the challenge of diagnosis and classification of hepatic nodules from small core needle or fine needle aspiration biopsies. New clinical guidelines for biopsy evaluation of nodules in cirrhosis, discussed by Jochen Lennert, Jeffrey Crippin, and Elizabeth Brunt, mean that most biopsies of nodules measuring less than 2 cm are from lesions with atypical radiographic features, and may be particularly challenging. A thoughtful diagnostic algorithmic approach to evaluation and reporting of such biopsies is provided, and should prove useful to the pathologist encountering these lesions. The problem of distinction of hepatic adenoma from well differentiated hepatocellular carcinoma is addressed by Melissa Kahn, Samuel French, and Hanlin Wang, who provide an up-to-date review of the newly described subclassification of adenomas and the clinical significance of these lesions.
Two rare hepatic tumors, hepatoblastoma and hepatic angiomyolipoma, are discussed by Hernan Correa and Raouf Nakhleh, respectively. These lesions, although not often encountered, present particular diagnostic challenges and it is important for the surgical pathologist to be aware of these entities. Cholangiocarcinoma, reviewed by Colin Pritchard and Matthew Yeh, is increasing in incidence, possibly as a result of Hepatitis C and alcoholic cirrhosis. Distinction from metastatic carcinoma remains problematic, and this review outlines recent immunohistochemical approaches that may be helpful in selected cases. This issue concludes with a review by Barbara Centeno of the challenges in interpreting fine needle aspiration biopsies from hepatic lesions, and a thorough review of application of immunohistochemical markers to the diagnosis of hepatocellular carcinoma by Daniela Allende and Lisa Yerian. We hope that you find this issue of Pathology Case Reviews interesting and informative.