Etiology

• The more common hepatocellular adenoma may be related to contraceptive use.

Epidemiology

• Liver cell adenoma is common in young women and may be related to the use of oral contraceptive medications.
• Bile duct adenomas are quite uncommon and may represent hamartomas or tumors due to developmental aberration.

General Description

• Hepatic adenomas are of two histological types: liver cell and Bile duct type.
• Liver cell adenomas are usually large when detected (25 - 30 centimeters in diameter), while bile duct adenomas are usually small, up to one centimeter in diameter.
• Liver cell adenomas can occur anywhere in the liver tissue, but are quite often seen under the capsule.
• Liver cell adenomas are usually pale to yellow in colour and may be bile stained.
• They are usually well demarcated, but the capsule may not be clearly obvious

Microscopic Appearance

• Histologically, a hepatocellular adenoma is composed of normal looking hepatocytes arranged in sheets and cords.
• Significant evidence of bile deposition may be seen within and between the cells
• Typical portal tracts and central veins are not seen, since the cells are not arranged in a typical lobular pattern.
• Bile duct adenomas are composed of slit - like to circular spaces lined by epithelium that resembles noram bile duct epithelium.
• However, significant vascular supply is a prominent feature.

Clinical features

• Clinically, both liver cell adenimas and bile cell adenomas are noncancerous lesions with little clinical significance.
• However, liver cell adenomas can become large sized during pregnancy, presumably as a result of estrogen stimulation
• Under these circumstances liver cell adenomas can rupture resulting in acute bleeding and peritonitis.

Liver cell adenomas may reduce in size in young women once they stop oral contraceptive ingestion.