A hepatic adenoma is an uncommon, non-cancerous tumor that develops from the primary cells of the liver, known as hepatocytes. These growths are benign, meaning they do not spread to other parts of the body. Hepatic adenomas are most frequently identified in women of childbearing age and are rare in the general population. The size of these tumors can vary significantly, from less than a centimeter to over 30 centimeters in diameter. While not cancerous, they require medical attention due to potential complications.
Causes and Risk Factors
The development of hepatic adenomas is strongly linked to hormonal influences, with the most common risk factor being the use of estrogen-containing oral contraceptives. The risk increases with the duration of use and the dosage of estrogen in the birth control pills. Hormonal shifts during pregnancy can also contribute to the growth of these tumors. The use of anabolic steroids is another significant risk factor.
Genetic predispositions can play a role, as certain changes in DNA can instruct liver cells to grow and divide abnormally. Underlying metabolic conditions are also associated with a higher risk of developing hepatic adenomas. These include glycogen storage diseases, where the body cannot properly store or break down glycogen, and hemochromatosis, a condition involving excess iron buildup. Additionally, metabolic syndrome and obesity are recognized as contributing factors.
Symptoms and Diagnosis
In many cases, a hepatic adenoma does not cause any noticeable symptoms. It is often discovered incidentally during imaging tests, such as an ultrasound or CT scan, for unrelated medical reasons. When symptoms do arise, they are the result of a large tumor pressing on adjacent organs. This can lead to pain in the upper right part of the abdomen, a feeling of fullness, or nausea.
If a liver tumor is suspected, a doctor will typically start with an ultrasound. To get a more detailed view and confirm the diagnosis, a magnetic resonance imaging (MRI) scan is often the preferred method. A CT scan may also be utilized. A biopsy, which involves taking a small tissue sample, is sometimes avoided because of the risk of bleeding from the adenoma.
Potential Complications
Although hepatic adenomas are benign, they carry two potential complications: hemorrhage and malignant transformation. Larger adenomas, particularly those exceeding 5 centimeters, have a greater tendency to rupture and bleed. This rupture can occur spontaneously, causing sudden, severe abdominal pain, internal bleeding, and a sharp drop in blood pressure, which constitutes a medical emergency.
The other primary concern is the possibility of the benign adenoma transforming into a type of liver cancer called hepatocellular carcinoma. This risk, while relatively low, is a key reason these tumors are closely monitored. The likelihood of malignant transformation is higher in men with hepatic adenomas and is also associated with larger tumor size. Certain molecular subtypes of adenomas, such as those with β-catenin mutations, are also believed to have a higher chance of becoming cancerous.
Treatment and Management
The management strategy for a hepatic adenoma is determined by its size, symptoms, and the individual’s specific circumstances. The first step is to address the underlying cause, which commonly involves discontinuing estrogen-based medications like oral contraceptives. This action alone can sometimes cause the tumor to shrink. Maintaining a healthy weight is also encouraged as part of the management plan.
For small, asymptomatic adenomas, the approach is active surveillance, involving regular imaging to track changes in the tumor’s size. Surgical removal is often recommended if an adenoma is large (over 5 cm in women), causing symptoms, or present in a male patient. The higher risk of complications in men often leads to recommending surgery regardless of tumor size. Surgical options include minimally invasive or open surgery, and in cases of acute bleeding, transarterial embolization may be used to block the tumor’s blood supply.