What Is a Keratoacanthoma?
Keratoacanthomas (KAs) are rapidly growing skin tumors that are generally considered part of the squamous cell carcinoma spectrum. They often appear as dome-shaped lesions with a central keratin-filled crater.
Although keratoacanthomas may sometimes behave differently from typical squamous cell carcinomas, they can still become large and locally destructive if left untreated.
Why Are Keratoacanthomas Different?
Keratoacanthomas are somewhat unusual because they often grow very quickly over a period of weeks. In some cases, they may later stabilize or even partially regress.
Historically, keratoacanthomas were sometimes considered separate from squamous cell carcinoma because of this behavior. Today, most are generally classified within the squamous cell carcinoma spectrum, although some aspects of these tumors remain incompletely understood.
What Causes Keratoacanthomas?
The exact cause is not fully understood. Factors that may contribute include:
- chronic sun exposure
- fair skin
- trauma or skin injury
- shaving-related nicks
- insect bites
- immunosuppression
Some patients notice these lesions appearing shortly after seemingly minor skin trauma.
Can Keratoacanthomas Go Away On Their Own?
Treatment depends on the size, location, and behavior of the lesion.
Options may include:
- surgical excision
- Mohs surgery in selected cases
- intralesional medications such as 5-fluorouracil (5-FU)
- other destructive or topical treatments in certain situations
Mohs surgery is recommended for rapidly growing lesions on cosmetically or functionally important areas such as the face.
What Are Eruptive Keratoacanthomas?
Some patients may develop multiple keratoacanthomas over a relatively short time. This is referred to as eruptive keratoacanthomas.
In certain cases, eruptive KAs may be associated with underlying medical conditions, such as internal malignancy, immunosuppression, or rare syndromes.
Final Thoughts
Keratoacanthomas are unique skin tumors with behavior that can differ from typical squamous cell carcinoma. Because these lesions may grow quickly and sometimes resemble more aggressive cancers, evaluation by a dermatologist is important.