Medical experts have revealed that humans can sometimes develop horns, not as mythical creatures, but due to a specific protein found in our own bodies. These growths, while rare, present significant health considerations that demand public awareness.
What Are Cutaneous Horns?
Cutaneous horns, known medically as cornu cutaneum, are compacted masses of keratin that protrude from a person's skin. Dan Baumgardt, a senior lecturer at the University of Bristol, explains that this is the same protein found in our skin, hair, and nails. Their hardened, often curved texture makes them resemble the horns of animals like goats or sheep.
These growths can appear in various colours, from yellow and brown to grey. Dan told The Conversation that the colour depends on the amount of pigment and dead cells trapped within the accumulating keratin structure.
Causes and Connection to Skin Cancer
Cutaneous horns develop from various types of skin lesions, many of which are harmless. Common benign causes include seborrhoeic keratoses—warty swellings frequently seen in older individuals—and other warts, including those caused by the human papilloma virus (HPV).
However, a significant 16-20% of these horns are malignant, developing from skin cancers such as squamous cell carcinoma. This cancer begins in the skin's outer layer and can invade deeper tissues if not treated promptly. Other horns arise from premalignant conditions like actinic keratosis, which has the potential to become cancerous over time.
In these concerning cases, cells lose their normal structure, leading to uncontrolled growth and excessive keratin production, which can form a horn.
Who Is Affected and When to Seek Help
These growths are far more common in older adults and people with fair skin. They frequently appear on sun-exposed areas like the head and face, indicating that ultraviolet (UV) light exposure is a major contributing factor. However, they have been documented in stranger locations, including the chest and genitals.
Dan Baumgardt strongly advises that anyone who notices a hard, growing bump that looks even faintly horn-like should see their GP immediately. "Their appearance can be distressing, especially when they form on visible areas like the face, and they may also cause discomfort or irritation," he said. Treatment typically involves surgical excision to remove the horn and a small margin of surrounding skin.
Historical Cases of Human Horns
The medical phenomenon has been recorded for centuries. In 2024, an elderly woman in China made headlines when a horn on her forehead grew to 10 centimetres over seven years.
The record for the longest human horn likely belongs to Madame Dimanche, also known as Widow Sunday, from early 19th century Paris. Her horn stretched nearly 25cm, hanging past her chin before it was surgically removed. A wax cast of her face and the remarkable horn is now displayed at the Mütter Museum in Philadelphia.
Ultimately, while fascinating, cutaneous horns are a potent reminder of the importance of skin health. Any unusual growth warrants a prompt consultation with a healthcare professional to ensure appropriate diagnosis and treatment.
