What Is Keratoacanthoma?

Keratoacanthoma is a rare, fast-growing benign tumor of the skin that has the characteristic of spontaneous regression, but is sometimes considered a variant of skin squamous cell carcinoma.

Basic Information

English name

keratoacanthoma

Visiting department

dermatology

Common locations

Facial

Common symptoms

There are skin lesions on the exposed parts of the face and upper limbs, with solid dome-shaped nodules, skin color or pale red, etc.

Clinical manifestations of keratoacanthoma

The disease can be divided into three types of single-type, multiple-type and rash-type keratoacanthoma.

Single hairstyle

Most commonly, it occurs mainly on the face, followed by exposed parts such as the upper limbs. The skin lesion was a solid dome-shaped nodule, skin color or light red, smooth surface, crater-shaped depression filled with horny plugs in the center, no infiltration of the base. The skin lesions develop rapidly and the course of disease is short. It can increase to 1 cm within a few weeks. After a few months, it may resolve on its own, leaving atrophic scars.

2. Multiple hairstyles

Rarely, it can be divided into multiple spontaneous regression (Ferguson-Smith syndrome) and multiple non-regression. Ferguson-Smith syndrome is an autosomal dominant hereditary disease, and the age of onset is usually 20 to 30 years. It is more common in men and can occur throughout the body. Skin lesions are smaller than those with a single hairstyle and rarely fade naturally.

3. Eruptive keratoacanthoma (Grzybowski type multiple keratoacanthoma)

The skin lesions consist of a large number of semicircular pimples with a diameter of 2 to 7mm. They are keratinized in the center and have normal skin color. It slowly subsided after several months. Patients often have scars, ectropion, and mask-like faces.

In addition, keratoacanthoma is associated with Muir-Torre syndrome (sebaceous tumor and gastrointestinal tumor syndrome), chemical exposure, immunosuppression, and HPV infection.

Keratoacanthoma

Histopathological manifestations of skin lesions are depressions in the epidermis, such as craters, which are filled with horn plugs, and the epidermal hyperplasia at the bottom extends irregularly into the dermis, with keratinized beads visible in the hyperplastic epidermis. The epidermis around the crater is lip-like, and squamous cells with large eosinophilic cytoplasm extended to the dermis, but did not fall off into the dermis. There are mitotic figures and squamous vortices. Significant inflammation in the dermis.

Keratoacanthoma treatment

Smaller skin lesions can be treated with topical 5% imiquimod cream, C0 ₂ laser, liquid nitrogen freezing, and photodynamic therapy.

Larger lesions can be removed by surgery.