What benign liver mass is typically asymptomatic and often discovered incidentally through imaging?

Focal Nodular Hyperplasia (FNH) is the most common benign liver mass and is often asymptomatic, making it frequently discovered incidentally during imaging studies conducted for unrelated reasons. The lesion is characterized by a hyperplastic reaction to a congenital malformation of the liver's blood vessels and does not form tumors like other liver lesions.

FNH typically presents as a well-circumscribed, solitary mass that may contain a central scar, distinguishable on imaging modalities such as ultrasound, CT, or MRI. Due to its benign nature and lack of symptoms in most cases, patients may remain unaware of its presence unless imaging is performed for other conditions or routine screenings. This incidental finding contributes to the importance of imaging in diagnosing liver lesions.

Other types of liver masses, such as hepatic lipomas, liver cell adenomas, and hepatocellular carcinoma, often have different clinical implications and may be symptomatic or possess other specific characteristics that differ from FNH, leading to a higher suspicion during clinical evaluations.