The involvement of the liver in systemic diseases.

The liver has a double blood supply and plays a central role in the metabolism of proteins, carbohydrates, and many medications. In addition, it has a role in the induction of immune tolerance and may also be a target for immune-mediated damage. For these reasons, the liver may be involved in many systemic diseases. In this review, we discuss the involvement of the liver in granulomatous, rheumatologic, malignant, and circulatory diseases. An understanding of the wide spectrum of liver involvement in systemic diseases will aid in both diagnosis and treatment of patients with a wide range of medical conditions.