Focal Nodular Hyperplasia

Excerpt

The liver is the only self-regenerative internal organ in the human body. This regenerative capability places the liver at an inherent risk for developing atypical masses. While the majority of liver masses present as predominantly solid or cystic masses, the etiologies are broad. In 1958, pathologist, Hugh Edmondson, MD, first described focal nodular hyperplasia (FNH) as a solid, benign hepatic mass of non-vascular origin. Unlike the most common liver mass which is the hemangioma, focal nodular hyperplasia is thought to be the result of increased hepatocyte number caused by hypoperfusion or hyperperfusion from anomalous arteries within the hepatic lobule. Focal nodular hyperplasia often is confounded by comorbid conditions making establishing a diagnosis and management difficult.

Previously, focal nodular hyperplasia was referred to by a variety of synonyms including pedunculated adenoma, solitary hyperplastic nodule, focal cirrhosis, and hepatic hamartoma. Because of the indeterminate classification, a standard diagnosis needed to be established. In 1994, the International Working Party of the World Congresses of Gastroenterology standardized the diagnosis term as follicular nodular hyperplasia and categorized it as a regenerative liver nodule. After that, follicular nodular hyperplasia was distinguished from neoplastic hepatic conditions.