What You Should Know About Cutaneous Horns

Medically Reviewed by Zilpah Sheikh, MD on April 24, 2024
5 min read

A cutaneous horn is a funnel-shaped growth that grows from a red base on the skin and is made of compacted keratin, the same protein in nails. It's shaped like an animal horn, but it is not made of bone. 

The first documented case of cutaneous horn is from the 1588 description of an elderly Welsh woman named Margeret Gryffith. For some centuries, people with cutaneous horns were ridiculed as circus-show oddities. In the mid-17th century, Danish anatomist Thomas Bartholin provided the medical reason for these horny growths: He described them as tissue tumor arising from the skin’s surface. 

How common are cutaneous horns?

Compared to other types of skin lesions, cutaneous horns are relatively uncommon. 

Who is most at risk?

Anyone can develop cutaneous horns. But cutaneous horns are more commonly found in people between the ages of 60 and 80 years old. In older people, cutaneous horns are more likely to be pre-malignant (precancerous) and malignant (cancerous). While anyone can get these growths, in men they are more likely to be cancerous. 

Cutaneous horns are caused by a variety of benign (noncancerous), precancerous, or cancerous processes in the skin. Doctors think cellular aging and sun damage play a role in causing them.

Common noncancerous causes of cutaneous horns

Seborrheic or lichenoid keratoses are the most common cause of benign cutaneous horns, according to the National Library of Medicine. Other noncancerous causes include:

  • Angiokeratoma 
  • Chronic skin irritation
  • Epidermal nevus
  • Hemangioma
  • Infections like human papillomavirus (HPV), molluscipoxvirus, or rhinosporidiosis
  • Juvenile xanthogranuloma
  • Pilomatricoma
  • Sarcoidosis
  • Sebaceous adenoma
  • Trichilemmoma

Common precancerous and cancerous causes of cutaneous horns

Actinic keratoses are the most common precancerous cause. Squamous cell carcinoma (SCC) is the most common cancerous cause. Other precancerous and cancerous causes include:

  • Arsenical keratosis
  • Basal cell epithelioma
  • Bowen’s disease 
  • Carcinoma
  • Kaposi’s sarcoma
  • Keratoacanthoma
  • Micaceous balanitis
  • Pseudoepitheliomatous keratosis
  • Verrucous carcinoma

In some cases, cutaneous horn has been linked to cancers in other parts of the body, such as renal cell carcinoma, a type of kidney cancer. 

Most of the time, a cutaneous horn doesn’t cause any symptoms. Some cutaneous horns may feel painful. Often this means some type of cancer is the cause.

What do cutaneous horns look like?

Cutaneous horns look like whitish or yellowish animal horns sticking out from the skin. Cutaneous horns can vary in color, dimensions, size, and shape. 

How big are cutaneous horns?

The width of the horn can range from a few millimeters to a few centimeters. The height of a horn is greater than the width, but still ranges from a few millimeters to a few centimeters. It’s rare for a cutaneous horn to reach more than 1 centimeter in height. 

Cutaneous horns up to 25 centimeters (almost 10 inches) in height have been reported. One case report published in the Annals of Medicine and Surgery was of a 61-year-old man in Italy who had a giant cutaneous horn growing from his forehead. He had the growth for more than 10 years. It was 10 to 11 centimeters (about 4 inches) in length and curled. Cutaneous horns can become large if you don't seek medical care for it and it continues to grow. 

How large and quickly it grows depends on if it is noncancerous, precancerous, or cancerous. Noncancerous cutaneous horns tend to grow slowly, over several months. Underlying cancerous causes, such as squamous cell carcinoma, can cause a horn to grow very quickly.

Where are cutaneous horns usually located?

Cutaneous horns can happen on many parts of the body. But they are usually located in areas with greater exposure to the sun. These include the:

  • Head
  • Neck 
  • Upper extremities, including the face, eyelids, and forearms 

Signs a cutaneous horn could be cancerous

You will need a biopsy to confirm whether a cutaneous horn is cancerous. In general, these signs are more likely to mean the cutaneous horn is cancer or has a cancerous cause:

  • Wider base 
  • Painful lesion
  • Inflammation around the horn
  • Height one to two times greater than the base diameter 

Your doctor or dermatologist will look at your skin to confirm that your growth is a cutaneous horn. That process is fairly simple. Though sometimes cutaneous horns may get confused with an ectopic nail.

To determine what’s causing your cutaneous horn, a specialist called a pathologist will need to examine the cells of the cutaneous horn under a microscope. For this, they will need to take a biopsy. Because they need to find out the underlying cause, they will  take out the entire horn.

Cutaneous horns are classified as either benign, premalignant, or malignant, and then by what’s causing them.

Cutaneous horns do not go away on their own. In the past, cutaneous horns were removed at the base and then that area of the skin was cauterized, or burned closed. Today the standard of care is complete removal of the horn and the root of the lesion deep in the skin. 

Cutaneous horn removal

Your doctor may remove your cutaneous horn with surgery or with a laser.

If you have basal cell carcinoma or squamous cell carcinoma, your doctor may order other tests to evaluate whether your cancer has metastasized or spread. You will also need to have follow-up evaluations for the first 3 years after diagnosis.

Because cancer may be the underlying cause of your cutaneous horn, you should see a doctor if you develop one of these lesions.

Practicing sun safety can help prevent these lesions from forming. To protect your skin from the sun:

  • Wear sunscreen daily.
  • Wear sun-protective clothing.
  • Seek shaded areas when outdoors.
  • Avoid peak UV radiation hours.
  • Perform monthly skin self-checks to look for new lesions.

Cutaneous horns are hard, cone-shaped lesions made out of keratin that grow out of your skin. Oftentimes, these lesions have a pre-cancerous or cancerous underlying cause. To figure out what’s causing your cutaneous horn, your doctor will need to take it out completely and biopsy it. Depending on what’s causing it will determine further treatment and follow-up. 

Do cutaneous horns need to be removed? Yes. Your doctor will need to remove your cutaneous horn from deep under the skin. This is the only way they can find out what is causing it to form. 

Can you trim cutaneous horns? No, your doctor needs to remove them.

Do cutaneous horns spread? They do not spread.

What is a cutaneous horn made of? Cutaneous horns are made of compacted keratin, the same protein found in your nails. 

Are cutaneous horns soft? No. Cutaneous horns are hard, cone-shaped lesions made of keratin.