liver cell adenomas

Adenoma of liver



Hepatic Adenoma:

This is a benign neoplasm arising from liver cells or hepatocytes. They are most common in young women and are associated with a history of oral contraceptive use. These tumors are important to recognize since they can clinically mimic a hepatocellular carcinoma, indeed, rare cases have harbored this cancer. These adenomas may also arise in the setting of glycogen storage disorders. Large subcapsular tumors do have a tendency to rupture, particularly during pregnancy.

On gross examination, these tumors are pale, yellow-tan, and may contain bile stained nodules. They are most commonly found beneath the capsule and may be multinodular. Occasional tumors may reach 30 cm.

Under the microscope, these tumors are similar to normal liver but are usually two to three cells thick. No bile ductules or portal triads are present in these lesions but central veins and large muscular arteries are present. There is minimal cytologic atypia. No mitoses or vascular invasion is present. Distinction of these tumors from other nodular lesions may be difficult. The following tables may provide a guide in microscopic distinction.

In addition to the differential diagnosis listed above, in children, there is additional diagnostic concern regarding hepatoblastoma, the fetal variant. The following table may be helpful.

Adenoma of liver

•A high power view of a liver cell adenoma, to demonstrate the cytological details of this tumor.
•The line of demarcation between the normal liver and the adenoma runs diagonally from the top left to the bottom right.
•The normal liver tissue is to the left of this line.
•The adenoma is to the right.
•It can be seen to be composed of cords of cells that are somewhat smaller than normal liver cells.
•The also have less abundant cytoplasm and are less eosinophilic
•They are arranged in cords like normal liver cells.
Adenoma

Etiology

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

•Unknown,
Epidemiology

•The more common liver cell adenoma is common in young women and may be related to the use of oral contraceptives.
•Bile duct adenomas are much less common and may represent hamartomas (developmental anomalies), rather than true adenomas.
General Gross Description
•Hepatic adenomas are of two histological types: liver cell and bile duct.
•Liver cell adenomas can be large (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 parenchyma, but are often seen under the capsule.
•Liver cell adenomas are pale to yellow and may be bile stained.
•They are usually well demarcated from the rest of the liver parenchyma, but the capsule may not be obvious.

General Microscopic Description

•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.
•However, significant vascular supply is a prominent feature.
•Bile duct adenomas are composed of slit-like to circular spaces lined by epithelium that resembles normal bile duct epithelium.
Clinical Correlation

•Clinically, both liver cell adenomas and bile cell adenomas are benign 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 peritonitis.
•A differential diagnosis of a liver cell adenoma is hepatocellular carcinoma.
•Liver cell adenomas may regress in young women once they stop oral contraceptive ingestion
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