Summary about Disease
Focal nodular hyperplasia (FNH) is a benign (non-cancerous) liver tumor. It is the second most common benign liver tumor, after hepatic hemangioma. FNH is composed of hepatocytes (liver cells) and other cell types arranged in an abnormal architecture. It typically presents as a solitary lesion, but can sometimes be multiple. While usually asymptomatic and discovered incidentally, FNH rarely causes complications and does not usually require treatment.
Symptoms
Most people with FNH have no symptoms. When symptoms do occur, they are usually vague and nonspecific and may include:
Abdominal pain or discomfort (usually in the upper right abdomen)
A feeling of fullness or pressure in the abdomen
Nausea
Rarely, a palpable mass in the abdomen
Causes
The exact cause of FNH is unknown. Several theories exist, including:
Abnormal blood vessel formation: It is thought that FNH may arise from an abnormal response of liver cells to altered blood flow within the liver.
Hormonal influence: Some studies suggest a possible link with oral contraceptive use, although this is not definitively proven.
Congenital factors: Some believe a developmental anomaly may be the underlying cause.
Medicine Used
FNH typically does not require medical treatment. If symptoms are present and related to the FNH, management is focused on symptom relief. Surgical intervention is rarely needed unless the FNH is very large, causing significant symptoms, or if there is diagnostic uncertainty. Medications are not typically used to treat FNH itself. Pain medications can be used for abdominal pain, if needed.
Is Communicable
Focal nodular hyperplasia is not communicable. It is not an infectious disease and cannot be spread from person to person.
Precautions
There are no specific precautions to take to prevent FNH as the cause is unknown.
How long does an outbreak last?
FNH is not an "outbreak" as it is not an infectious disease. FNH is a growth of the liver, once formed it generally persists. While it can remain stable in size over many years, it also may slowly grow.
How is it diagnosed?
FNH is typically diagnosed through imaging studies. Common diagnostic methods include:
Ultrasound: Initial imaging test, can sometimes identify a lesion.
CT scan (Computed Tomography): Provides detailed images of the liver.
MRI (Magnetic Resonance Imaging): Often the preferred imaging modality as it can provide more specific information about the lesion, including the presence of a central scar, a characteristic feature of FNH.
Liver Biopsy: In some cases, a biopsy may be necessary to confirm the diagnosis, especially if imaging is inconclusive or if there is concern about malignancy.
Timeline of Symptoms
FNH is often asymptomatic and discovered incidentally during imaging for other reasons. When symptoms are present, they are typically chronic and may develop gradually over time. There is no specific timeline as symptom development varies widely among individuals.
Important Considerations
Differentiation from other liver lesions: It is crucial to differentiate FNH from other liver lesions, particularly hepatocellular adenoma (HCA) and hepatocellular carcinoma (HCC), as these conditions have different management strategies.
Monitoring: Although FNH is benign, regular monitoring with imaging studies may be recommended to assess for growth or changes in the lesion, especially in younger patients or those with large lesions.
Oral Contraceptives: If a woman is diagnosed with FNH, the potential role of oral contraceptives should be discussed with her physician. While the association is not definitively proven, some experts recommend discontinuation of oral contraceptives.
Pregnancy: FNH generally does not pose a significant risk during pregnancy, but monitoring may be considered.
Rare Complications: Very rarely, FNH can cause complications such as bleeding or rupture, especially if the lesion is very large.