What Is a Skin Horn (Cutaneous Horn)?

A skin horn (also known as a cutaneous horn or cornu cutaneum) is a lesion that resembles an animal horn.  The horn is a hard outgrowth of abnormally shaped tissue made of keratin—the primary protein of the surface layer of skin that forms its rigidity and provides barrier protection. Keratin is also found in the nails and hair. 

The anomaly gets its name because it curves upward as it grows, causing it to appear like the horn of an animal. The very first case of a skin horn was documented in 1588 in an elderly Welsh woman named Mrs. Margeret Gryffith.

Skin Horn Symptoms

A cutaneous horn is a growth on the skin that can appear like a horn. Some characteristics of a cutaneous horn include:

• It looks cone-shaped or appears as a spike or a large bump.
• It may be pink, red, whitish, or skin-colored, but most often it is a yellowish-brown color.
• Its height is described as being more than half the diameter of its base.

The growth can be found on different areas of the body, but according to a 2010 study, it is most commonly present in areas exposed to the sun, such as the face and head.

Other areas in which a cutaneous horn may be found include:

• Upper limbs
• Chest
• Upper arms
• Ears
• Hands
• Scalp
• Lips

In some instances, there are symptoms such as induration (a localized hardened area of soft tissue) or inflammation at the base of the skin horn, which may indicate the presence of underlying squamous cell carcinoma.

A 2018 study found that areas of the body that are exposed to the sun, such as the backs of the hands, nose, scalp, and forearms, have twice the risk of having a pre-malignant or malignant lesion on the base of the cutaneous horn when compared with other areas of the body. Skin horns on the face and the cartilaginous area of the ears are also commonly linked with malignancy (cancer).

Causes

A cutaneous horn may arise from various lesions, including:

• A viral wart
• Bowen's disease
• Seborrheic keratosis
• Actinic keratosis
• A benign (noncancerous) lesion
• A pre-malignant (precancerous) lesion
• A malignant (cancerous) skin lesion

The reason some people get skin horns and others don’t is unknown.

A 2010 study found that women were slightly more likely than men to get a cutaneous horn. The study also reported that the skin irregularity occurs most often in people between 60 and 70 years of age. Among the 222 cutaneous horn cases studied, 41% of the lesions were benign and 59% were found to be pre-malignant or malignant.

Diagnosis

Diagnosis of a cutaneous horn is usually made by conducting a visual inspection as part of an examination. Often, a biopsy is performed once the skin horn is removed, because of the high incidence of pre-malignant and malignant lesions.

A biopsy includes removing the skin horn, then sending it to the lab to be examined under a microscope for the presence of cancerous cells.

Treatment

The treatment of a cutaneous horn depends on what type of lesion is involved.

Cutaneous Horn Removal

If the lesion that is the underlying cause of a skin horn is benign (noncancerous), it is often treated by excision (surgical removal or resection) or with a procedure called curettage. This is a medical procedure involving the removal of tissue by scraping or scooping.

Cancerous Lesions

If squamous cell carcinoma (SCC) is the culprit, the treatment depends on the stage of cancer, which denotes whether cancer has spread. When SCC is found early on, there are several types of treatment, including:

• Excisional surgery: Surgery to remove the cancerous tissue
• Mohs surgery: A procedure that aims to remove the skin cancer while sparing as much healthy tissue as possible
• Cryosurgery: Using a freezing technique to destroy cancer cells
• Curettage and electrodesiccation/electrosurgery: A procedure, usually performed on an outpatient basis, that involves scraping away the top layers of skin and heating the surface of the affected area with a metal instrument or needle that delivers an electric current (electrosurgery)
• Laser surgery: A type of surgery that uses the cutting power of a laser beam to make bloodless cuts in tissue or remove a surface lesion such as a skin tumor
• Radiation: The use of high-energy radiation from X-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors
• Photodynamic therapy: A type of treatment that uses light cells along with photosensitizing agents (special drugs) to kill cancer cells

Prognosis

The prognosis of a disease is an estimate of its treatment outcome, based on medical research studies that evaluate many others having been treated for the same disease. The prognosis of skin horn treatment depends largely on the type of underlying lesion linked with the anomaly.

A Word From Verywell

If you have a skin horn associated with cancer, such as squamous cell carcinoma (SCC), be sure to discuss treatment options with your healthcare provider. The exact type of cancer treatment depends on many factors, including your age, overall health, and the size, location, and depth of the lesion, as well as whether the cancer is localized or has metastasized (spread) to other areas. 

Work with your healthcare team to determine the best course of treatment for you.