Hepatic Adenomatosis in a Young Asymptomatic but High-risk Patient: An Incidental Diagnosis with Potentially Severe Clinical Implications

Hepatic adenomatosis (HA) is a very rare condition and defined as the presence of 10 or more adenomas in an otherwise normal liver. HA has an incidence of 10–24% in patient with hepatic adenoma and it is more common in women. Most patients with HA are asymptomatic with a normal liver function test and half of cases are detected incidentally on imaging. Although HA is considered a benign disease, some patients may develop potentially fatal complications, such as hypovolaemic shock due to rupture of the liver lesion or malignant transformation to hepatocellular carcinoma. We report the case of a 29-year-old woman who presented to the emergency room after a car accident. Whole-body computed tomography revealed multiple focal hepatic hypervascular lesions in the right lobe of the liver together with a fatty liver. Subsequent hepatic magnetic resonance imaging suggested the diagnosis of HA with a suspicion of focal nodular hyperplasia (FNH). The patient refused to undergo liver biopsy, so we instituted a 3-month surveillance program, which included clinical assessment, liver function tests, tumour marker assessment and blood tests as well as sonographic evaluation for follow-up of the liver lesions. LEARNING POINTS: Hepatic adenomatosis is an extremely rare disease which predominantly affects women and is associated with hormone consumption, liver steatosis, glycogen storage disease, obesity, metabolic syndrome, abnormalities of hepatic vasculature and maturity onset diabetes of the young (MODY). The two main differential diagnoses include focal nodular hyperplasia (FNH) and well-differentiated hepatocellular carcinoma. Histological confirmation is required when MRI findings are inconclusive or when a malignancy is suspected. In men, resection of adenomas is mandatory due to the high risk of malignant transformation. In woman, a conservative approach with contraceptive discontinuation and biannual follow-up with MRI and alpha-fetoprotein is recommended; resection is needed in case of positive immunohistochemical staining for β-catenin on biopsy, symptomatic adenomas, adenoma increasing in size, and when malignancy cannot be ruled out.