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Keratoacanthoma
Aka: Keratoacanthoma
- Pathophysiology
- Benign epithelial lesion
- No longer thought to be associated with malignancy
- Not a squamous cell cancer variant
- May be difficult to distinguish from SCC (see below)
- Causes
- Ultraviolet light exposure
- Human Papillomavirus
- Coal tar derivative exposure
- Signs
- Characteristics
- Initial
- Red to skin-colored dome-shaped Papule
- Smooth surface
- Central umbilicated keratinous core
- May reach up to 2 cm in size
- Rapid growth
- Later (after 4-6 months)
- Lesion regresses
- Keratin core expelled
- Hypopigmented scar remains
- Distribution (sun-exposed areas)
- Face
- Extremities
- Differential Diagnosis
- Squamous Cell Carcinoma
- Similar grossly and histologically to Keratoacanthoma
- Management
- Smaller Keratoacanthoma
- Electrodessication and Curettage
- Blunt Dissection
- Larger Keratoacanthoma
- Excision
- Moh's Surgery for difficult areas
- Other options
- Topical agents
- 5-Fluorouracil 5% cream
- Apply during rapid growth tid
- Use under tape Occlusion
- Effective in 1-6 weeks
- Podophyllum 25% in benzoin
- Remove central crust and apply every 2 weeks prn
- Apply in clinic only due to high concentration
- Intralesional injections during rapid growth phase
- 5-Fluorouracil intralesional injection
- Methotrexate intralesional injection
- 5-Interferon alfa-2a injection
- Oral agents (for multiple lesions)
- Isotretinoin (Accutane)
- Radiotherapy
- Indicated for difficult cosmetic areas
- References
- Habif (1996) Dermatology, Mosby-Year, p. 638
- Luba (2003) Am Fam Physician 67(4):729-37