Hyperostosis Frontalis Interna: Causes, Imaging, and Management

What Is Hyperostosis Frontalis Interna?

Hyperostosis frontalis interna (HFI) is a benign condition that leads to an abnormal thickening of the inner side of the forehead bone (frontal bone) than its normal thickness. It develops slowly and is most common in aged women, particularly after menopause. Generally, it causes no symptoms, but sometimes in rare cases, it may cause headache, memory changes, etc.

What Are the Types of Hyperostosis Frontalis Interna?

Doctors classified HFI into four types based on factors like how the bone growth looks and how much it covers the forehead bone. They are -

Type A - Isolated bone growths covering less than 25 percent of the frontal bone.

Type B - Bone growths covering 25 percent of the frontal bone.

Type C - Bone growths covering 50 percent of the frontal bone.

Type D - Bone growths covering more than 50 percent of the bone.

What Are the Clinical Features of Hyperostosis Frontalis Interna?

Excessive growth or thickening of the head's frontal bone is the main characteristic of hyperostosis frontalis interna. However, only an X-ray can show this excessive development. Because of this, experts believe this ailment may be far more common than previously thought, but it frequently goes undiagnosed. Many people do not seem to have any symptoms.

This disorder may also be associated with -

• Decreased vision.

• Headaches.

• Abnormalities of the ovaries and testes (sex glands or gonads).

• Excessive body hair.

• Diabetes.

• Obesity.

• A condition in which secondary male sexual traits are acquired by a female.

• A central nervous system disorder called epilepsy, which is characterized by an abrupt, aimless, uncontrollable discharge of electrical energy in the brain that causes a convulsion or loss of consciousness.

How to Diagnose Hyperostosis Frontalis Interna?

When HFI is suspected, the doctor will question you about your symptoms and history and run through various tests, which include blood tests and imaging studies. Let's see about them in brief -

• Evaluate Patient History and Symptoms - When HFI is detected on a scan (usually by chance or when radiological imaging of the frontal bone imaging is done for some other issue), your treating doctor will look for obesity (excessive weight), menopause in women, hormonal problems related to thyroid, adrenal, or pituitary glands, changes in hair growth, seizures, or headaches.

• Blood Test - To determine whether other illnesses could be causing bone defects, your doctor might perform specific blood tests to check the levels of calcium and alkaline phosphatase, parathyroid hormone, and insulin-like growth factor. A high calcium and alkaline phosphatase level may indicate active bone growth. These tests also assist in excluding other conditions that resemble HFI.

• X-rays - It is the first step in examining bone growth. However, X-rays may fail to detect tiny and immature bone growths.

• CT (Computed Tomography) Scan - This is the ideal imaging technique for clearly viewing the middle spongy bone and inner and outer bony layers. A CT scan clearly shows the extent, appearance, and location of the thickened bone.

• Bone Scan (Bone Scintigraphy) - This scan helps detect active bone growth using a radioactive tracer.

• Single Photon Emission-CT - This type of imaging combines bone scan and computed tomography to obtain a clear image of the bony growths. It also helps prevent misdiagnosis of metastasis and confirms HFI.

• Positron Emission Tomography-CT - This helps detect and identify alterations before they become significant and exhibit early bone activity.

What Is the Management of Hyperostosis Frontalis Interna?

HFI management depends on the symptoms that you or someone you know experiences, which include -

• Standard painkillers, such as NSAIDs (non-steroidal anti-inflammatory drugs) or other painkillers like Acetaminophen, can be used to treat headaches.

• Surgery is considered in some individuals when the pressure from the bone overgrowth is causing significant symptoms like headaches, seizures, memory loss, or difficulty concentrating.

• HFI can sometimes be linked to other illnesses such as hyperparathyroidism (the parathyroid gland produces excess parathyroid hormones), acromegaly (excess growth hormone in your body), or specific metabolic diseases like diabetes mellitus (increased blood sugar levels) and diabetes insipidus (increased thirst and urination). Management of the underlying condition should be the main goal of treatment if one is found.

• HFI is one of the components of the classic triad seen in Morgagni syndrome (also includes obesity and excessive hair growth in a male pattern in females). So, if the person experiences this syndrome, treatment should focus on controlling obesity, excess hair growth, and HFI-related headaches.

How to Prevent Hyperostosis Frontalis Interna?

Since we are not aware of the exact cause of the condition, there is no way to prevent it. Several studies have shown that the cause can be hormonal or hereditary, but none of them can be prevented. However, you can take some measures to improve your overall health, which include -

• Controlling your weight.

• Managing hormonal imbalances.

• Treating underlying health conditions.

When to See a Doctor?

If an imaging study shows thickened frontal bone, even without any symptoms, you must consult a radiologist online to rule out other causes. Also, if you have any of the below-mentioned symptoms, you must discuss them with your doctor without further delay.

• Severe headaches.

• Seizures.

• Memory loss.

• Bulge in the forehead.

• Unexplained weight gain.

• Hormonal issues.

• Excessive hair growth.

If you fail to report your health issues on time, it might worsen your health. So, it is always better to discuss the symptoms you experience with your doctor promptly to avoid any complications and to manage the condition better.

Conclusion

HFI is the abnormal thickening of the frontal bone (frontal bone sclerosis) due to endosteal bone formation.

It is usually diagnosed by chance while taking X-rays for some other illness, specifically in postmenopausal women. Since asymptomatic, treatment is not required; in rare cases, surgery is needed to alleviate headache and seizures.

Get expert radiologist advice online if you experience any symptoms related to HFI.

Key Takeaway From iCliniq

• Hyperostosis frontalis interna is the thickening of the frontal bone’s middle layer.

• In general, this condition does not cause symptoms. However, in rare cases, it can cause symptoms like headaches, seizures, and memory loss.

• If you are unsure about your diagnosis, at iCliniq, our radiologist consultation will analyse your imaging studies and guide you on the right path to improve your overall health.