Learn all about focal nodular hyperplasia. Focal nodular hyperplasia (FNH) is a regenerative mass lesion of the liver and the second most common benign liver lesion (most common is a hemangioma). Many FNHs have characteristic radiographic features in multimodality imaging, but some lesions may be atypical in appearance. FNHs are typically asymptomatic lesions usually requiring no treatment.
Focal nodular hyperplasia (FNH) lesions are benign liver lesions characterized by the presence of a vascular red-brown or tan mass with nodules of benign hepatic parenchyma laced with fibrous septa that may extend out from a broad central stellate scar. FNH is more common in premenopausal women, although up to 10% may occur in males.
Lack of symptoms, normal liver enzymes and no prior use of oral estrogen containing contraceptives make FNH more likely than adenoma. If the differentiation with adenoma cannot be made, open biopsy should be performed; if FNH is confirmed, no resection is necessary. In FNH low dose estrogens can be safely continued and pregnancies without difficulties have been reported.
The lesions are often detected incidentally during imaging for non-specific symptoms of the abdomen and, once the diagnosis has been established, active treatment is almost never required.
Although FNH tumors are benign, it can sometimes be hard to tell them apart from true liver cancers. The main difficulty in management of FNH is the difficulty in differentiating it from liver adenoma and liver cancer.
What is Focal Nodular Hyperplasia?
Focal nodular hyperplasia (FNH) is the second most common tumor of the liver, surpassed in prevalence only by hepatic hemangioma. FNH is believed to occur as a result of a localized hepatocyte response to an underlying congenital arteriovenous malformation. FNH is a hyperplastic process in which all the normal constituents of the liver are present but in an abnormally organized pattern.
Focal Nodular Hyperplasia Size
It is a benign, tumor-like lesion consisting of hyperplastic parenchymal nodules with abundant abnormal vessels typically arising from a central stellate-shaped scar. Most (86- 91%) occur in women of reproductive age but convincing cases have also been described in men and children (1-4). In a study of 18 men and 216 women with FNH, mean FNH size was significantly smaller in men (37.5 mm in men vs. 63.4 mm in women). The striking female predominance and size difference suggests a hormonal dependence. In the majority of the cases, the FNH is discovered incidentally. Symptoms that prompt discovery include recent to chronic abdominal pain or discomfort, palpable mass and constitutional symptoms such as weight loss, weakness, and fever. FNH lesions are usually solitary, but multiple lesions are not rare (15-24%). The characteristic gross appearance of FNH is a circumscribed, but unencapsulated, bulging, tan, lobulated, nodular mass. A central stellate scar with radiating fibrous septa has been emphasized as a hallmark feature of FNH, but approximately half of cases lack this finding.
Focal Nodular Hyperplasia Removal
Liver resection is the removal of a part of the liver that is diseased or affected. In focal nodular hyperplasia, the part of the liver where there is tumor growth is removed. The healthy part of the liver is left unharmed. A person can still continue normal functioning despite the removal of one part of the liver.
Focal Nodular Hyperplasia Growth
Although FNH may grow to more than 10 cm, patients are occasionally symptomatic, and most show a normal liver function test. Malignant transformation of FNH has not been clearly described.
Focal Nodular Hyperplasia Diagnosis
Magnetic Resonance Imaging (MRI) scans of the liver are the best imaging technique to diagnose FNH accurately. Multi-phasic CAT scans can also diagnose FNH but unlike MRI scans they do expose the patient to radiation. The central scar is the characteristic sign of FNH. The only differential diagnosis in a lesion with a central scar to be considered is fibrolamellar cancer of the liver. If the central scar cannot be visualized, differentiation from adenoma can be difficult.
A diagnosis of Focal Nodular Hyperplasia of the Liver may involve:
- Most FNH cases may be diagnosed, via a physical examination. If the physician notes any stiffness or hardness, when pressing upon the liver; then, a mass such as FNH is suspected. Furthermore, gathering information on the individual’s health and personal habits, serves as a good indicator to their risk of developing this benign liver tumor. If the risks are evident, then the physician may suspect Focal Nodular Hyperplasia.
- Focal nodular hyperplasia (FNH) can be diagnosed with the use of imaging studies such as a color Doppler. Upon diagnosis a focal nodular hyperplasia would appear like a “comet tail”. This is because FNHs are hypervascular in nature; upon Doppler studies scattered veins and arteries are seen throughout the liver, giving a comet like appearance.
- Imaging studies: Such studies can confirm a healthcare provider’s diagnosis. Using radiological tests, such as CT scan of the abdomen, MRI scan of abdomen, and abdominal ultrasound, the presence of a liver tumor can be imaged.
- When, neither a physical examination nor an imaging study, can confirm the diagnosis, a biopsy may be conducted. During a biopsy, a sample of tissue from the suspected hepatic tumor is collected and sent for examination, to a laboratory. A pathologist studies the specimen under a microscope, in order to make a definitive diagnosis.
Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
Focal Nodular Hyperplasia Treatment
- Focal nodular hyperplasia treatment includes the surgical interventions. The tumors can sometimes disappear without any treatment. FNH does not require surgical removal in all cases. It is important to follow a healthy diet and lifestyle to avoid excess inflammation in the liver.
- A good liver tonic and supplements of selenium and N Acetyl Cysteine (NAC) may help to reduce liver inflammation and support optimal liver function.
- If you are overweight, it is important to follow a low carbohydrate eating plan as fatty liver will worsen FNH