Metabolic disorders of the liver

Metabolic diseases could be inherited as inborn errors of metabolism or acquired. In this review we discuss some of the metabolic disorders likely to present in the adult population and in which liver biopsy could be indicated as part of diagnosis or treatment. These include iron overload/hemochromatosis, Wilson's disease, alpha-1-antitrypsin deficiency, Niemann–Pick's disease and Gaucher's disease with emphasis on characteristic or helpful histopathologic features. In this era of molecular and other non-invasive analyses, the role of liver biopsy for primary diagnosis has decreased but is still an important tool for supplementing clinical/molecular diagnosis, staging disease and as a guide to management. In addition to qualitative assessment, quantitative measurements of iron and copper per unit dry weight of liver tissue can be performed on paraffin-embedded blocks and should be considered in patients being treated for iron overload or being worked up for possible Wilson's disease respectively. Gaucher's disease and Niemann–Pick's disease are examples of lysosomal storage diseases that could present outside of the pediatric population; these diseases have fairly distinguishing features that could be used to triage which patients need additional enzyme or other assays for definitive diagnoses. While non-alcoholic steatohepatitis remains the commonest metabolic liver disease in adult population, the pathologist should also be aware of these other entities discussed in this review.