hepatic and biliary disorders
Benign Liver Tumors
Hepatocellular Adenoma
 effects ( References ). Most adenomas are asymptomatic, but large ones may cause right upper quadrant discomfort. Rarely, adenomas manifest as peritonitis and shock due to rupture and intraperitoneal hemorrhage. Rarely, they become malignant. Diagnosis is often suspected based on ultrasound or CT results, but biopsy is sometimes needed for confirmation. Gadoxetate-enhanced MRI is more sensitive than CT and can differentiate subtypes of adenomas at increased risk of progressing to malignancy ( References ). Recognition of the beta-catenin subtype is particularly important, because it has a 5 to 10% risk of malignant transformation and should be resected. Adenomas due to contraceptive use may regress if the contraceptive is stopped. If the adenoma does not regress or if it is subcapsular or>5 cm, surgical resection is often recommended. 1.Marrero JA, Ahn J, Rajender Reddy K, et al: ACG clinical guideline: The diagnosis and management of focal liver lesions.Am J Gastroenterol109(9):1328-1347, 2014. doi: 10.1038/ajg.2014.213 2.Bieze M , van den Esschert JW , Nio CY, et al: Diagnostic accuracy of MRI in differentiating hepatocellular adenoma from focal nodular hyperplasia: Prospective study of the additional value ofgadoxetate disodium.AJR Am J Roentgenol199:26– 34, 2012. doi: 10.2214/AJR.11.7750 