Large keratoacanthomas treated with intralesional interferon alfa-2a.

Background: Spontaneous involution of giant keratoacanthomas (KAs) can leave large scars or cause mutilation. Human papillomaviruses have recently been demonstrated in KAs. Intralesional interferon alfa-2a (IFN alfa-2a) has been shown to have activity against different epithelial tumors and to have an antiviral effect.

Objective: This study was conducted to determine whether it was possible to stop extension of large KAs, to accelerate healing, and to obtain good cosmetic results with intralesional IFN alfa-2a.

Methods: Six large KAs were treated with intralesional IFN alfa-2a.

Results: Regression was obtained in five cases in 3 to 7 weeks with excellent cosmetic results. The main side effect was pain during injection.

Conclusion: Our results suggest that this treatment hastens healing and limits scarring.