Keratoacanthoma
Also known as: KA
Rapidly growing dome-shaped nodule with a central crater. Most dermatologists treat it as low-grade SCC.
What to look for
Side-by-side comparison
Normal skin
No rapid growths
Keratoacanthoma
Dome + central crater, rapid
Keratoacanthoma grows from nothing to 1-2cm within 4-8 weeks - a dome-shaped nodule with a central keratin-filled crater giving a volcano-like appearance.
Classification is debated. Historically considered benign (can spontaneously resolve), many dermatologists now regard it as well-differentiated SCC. Due to difficulty distinguishing KA from SCC on biopsy, excision rather than observation is recommended.
Most commonly occurs on sun-exposed skin of middle-aged and elderly individuals.
Quick self-check
Does this look like keratoacanthoma? Answer 2 questions.
Did it appear rapidly - within weeks?
Does it have a dome shape with a central crater?
Risk factors
- Chronic sun exposure
- Fair skin
- Age over 50
- Immunosuppression
- Previous skin trauma
When to see a dermatologist
- ⚠Any rapidly growing dome-shaped nodule
- ⚠A skin lump with a central crater or keratin plug
- ⚠A new growth enlarging quickly on sun-exposed skin
Often confused with
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Full ABCDE check →Frequently asked questions
Is keratoacanthoma benign or malignant?
Debated. It can regress spontaneously (suggesting benign) but is now widely treated as well-differentiated SCC because some behave aggressively. Most dermatologists err on caution and excise.
Will it go away on its own?
Classic KAs can involute over 4-6 months. But since it is impossible to reliably distinguish from SCC, excision is recommended. Watching a potential SCC grow is too risky.