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.
Sources
Based on clinical guidelines from the American Academy of Dermatology (AAD) and British Association of Dermatologists (BAD). Statistics from NCI SEER Program and IARC GLOBOCAN. Staging per AJCC Cancer Staging Manual, 8th ed. Full methodology