What is the recommended treatment for Keratoacanthoma?

Treatment of Keratoacanthoma

Surgical excision is the recommended first-line treatment for keratoacanthoma due to its ability to provide complete removal with histological confirmation and reduce the risk of local recurrence. 1, 2

Understanding Keratoacanthoma

Keratoacanthoma (KA) is considered a variant of squamous cell carcinoma (SCC) that typically presents as a rapidly growing, dome-shaped lesion with a central keratinous plug on sun-exposed areas. While some KAs may spontaneously regress over 6-12 months, treatment is recommended due to:

• Difficulty in reliably distinguishing it from SCC clinically 2
• Reports of aggressive behavior and potential for local tissue destruction 2
• Risk of malignant transformation 3
• Possibility of intravascular/perineural invasion and lymph node metastases in rare cases 3

Treatment Algorithm

1. First-Line Treatment: Surgical Excision

• Standard surgical excision: With 4-6 mm margins for well-defined, low-risk tumors 1
• Mohs micrographic surgery (MMS): Particularly valuable for:
  • Lesions in cosmetically sensitive areas (face, ears, scalp) 4
  • Large tumors (giant keratoacanthomas >20-30mm) 4
  • High-risk locations (ear, lip, scalp, eyelids, nose) 1

2. Alternative Treatments (when surgery is contraindicated or not preferred)

For smaller, well-defined lesions:

• Cryosurgery: Using double freeze-thaw cycle 2
• Curettage and electrodesiccation: May require multiple cycles for thicker lesions 2

For lesions in cosmetically sensitive areas or in poor surgical candidates:

• Intralesional methotrexate (MTX):
  • Initial debulking followed by MTX injection (12.5-25mg per injection) 5
  • Usually requires 2-4 weekly injections 5
  • 88-100% cure rate reported in studies 5, 6
  • Particularly effective for multiple KAs (100% clearance in one study) 6

For periocular areas:

• Cryosurgery with contact probe 2

For advanced or aggressive lesions:

• Radiation therapy: For inoperable KAs or nonsurgical candidates 1
• Adjuvant radiation: For high-risk features like perineural invasion 1

Special Considerations

Immunosuppressed Patients

• Require more aggressive management 2
• May benefit from systemic retinoids to reduce risk of subsequent lesions 1

Multiple or Eruptive KAs

• Intralesional MTX has shown 100% clearance in one study 6
• Systemic retinoids can be used in combination with targeted treatments 1
• Topical 5-fluorouracil under zinc oxide-impregnated compression bandages (chemowraps) may be effective 1

Follow-up Recommendations

• Regular skin examinations for recurrence or new lesions 2
• Histological evaluation of any lesion that fails to respond to treatment 2

Important Caveats

• KAs that appear to be regressing should still be treated, as evidence that all KAs regress is lacking 7
• Less than excisional biopsy may render a difficult histologic diagnosis inconclusive or erroneous 7
• When intralesional MTX fails, surgical excision should be performed 6
• Immunosuppressed patients are at higher risk for developing KAs and may require more intensive monitoring 2

By following this treatment algorithm, clinicians can effectively manage keratoacanthomas while minimizing morbidity and optimizing cosmetic outcomes.