Pathology of hepatic iron overload

The role of liver biopsy in all chronic liver diseases continues to evolve with the emergence of new laboratory and imaging tests. However, the value of histologic examination for fibrosis, parenchymal architectural remodeling, and possible concurrent disease remains relatively unchallenged, including in patients with suspected iron overload. In addition, only histologic evaluation allows detailed analysis of cellular and acinar localization of iron. Routine use of an iron stain for all liver biopsy analysis enables detection of iron when not otherwise suspected. The broad classifications of iron overload include parenchymal ("primary") or reticuloendothelial ("secondary"), and mixed. These classifications, however, serve only as guidelines to differential diagnoses, as will be noted in the following review of pathology of iron overload. Ultimately, the role of the pathologist is to document cellular and acinar localization of iron and to provide a semiquantitative assessment of amount to alert the clinician to the possibility of a significant condition. In this article, histopathologic findings in conditions of iron overload and in several forms of liver disease are discussed.