**Abstract**

Hepatic adenoma is known as a benign lesion encountered mainly in female patients and classically linked to the administration of oral contraceptives. In the last decade, the risk factors for its occurrence have changed and so did the sex ratio. The histopathological classification of hepatic adenomas was found to be related with certain genetic mutations that determine the risk for malignancy. The diagnosis of hepatic tumor is correlated with clinical and imaging data in an effort not only to rule out other tumors but also to distinguish the subtype of adenoma, which is very important for the management of the patient. The ultimate diagnosis is established by pathologists by routine histopathological and specific immunohistochemical staining. There are two major issues that pathologists need to recognize: the presence of β-catenin gene mutation and/or malignant degeneration. The best imaging examination is considered to be MRI. However, along with MRI, ultrasound and computer tomography have proved themselves to be effective not only in evaluating the number, size, localization, and complications of hepatic adenomas, but also in identifying their subtype. A detailed presentation of characteristics of all groups of hepatic adenoma is provided. The means of management of hepatic adenomas are documented and decisional algorithm is explained, based on certain criteria.

**Keywords:** hepatic adenoma, hepatocellular adenoma, liver adenoma, adenomatosis, hepatectomy, laparoscopic hepatectomy, liver transplantation, liver imaging

### **1. Introduction**

Hepatic adenoma (HA) is a rare, benign tumor of epithelial origin (2% of all liver tumors [1]) that develops usually in healthy liver [2] and is known to occur mainly in young female patients, having been linked to the prolonged use of oral contraceptives [3]. In Europe and North America, it has an incidence of 3/100,000/ year [4]. Even though multiple hepatic adenomas have been described in the literature, this is a rare occurrence, most of the adenomas being solitary (70–80%), and thus, often asymptomatic unless they become complicated (voluminous adenomas causing upper quadrant pain and/or rupture of the tumor with hemoperitoneum and malignant transformation) [5]. Hepatocellular adenoma is a term sometimes used instead of hepatic adenoma, being correct in contradiction to liver adenoma

or liver cell adenoma, which are less desirable because these two can also include the bile duct adenoma [6]. Even though the prognosis of this type of tumor is not well established, it is important to differentiate it from other hepatic tumors since the hepatic adenoma has a particular therapeutic management. Differential diagnosis however can be challenging, but can be achieved preoperatively by imaging techniques. Positive diagnosis is a histopathological one and is often obtained postoperatively [7].
