Focal nodular hyperplasia (FNH) is the second most common benign tumor of the liver, after hemangioma. Unlike the most common liver mass which is the hemangioma, focal nodular hyperplasia is thought to be the result of increased hepatocyte. Focal nodular hyperplasia (FNH) is a benign tumor of the liver (hepatic tumor), which is the second most prevalent tumor of the liver It is usually asymptomatic,. Focal nodular hyperplasia liver lesions, also called FNH, are tumors characterized by the presence of a vascular mass with nodules. Focal nodular hyperplasia (FNH) is a regenerative mass lesion of the liver and the second most common benign liver lesion (most common is a hemangioma).