Intralesional Methotrexate for the Treatment of Keratoacanthoma: Retrospective Study and Review of the Korean Literature

Background: Although intralesional methotrexate (MTX) is an effective, nonsurgical treatment of keratoacanthoma (KA), there have not been many reports of on the MTX treatment for KA in Korea. Objective: The purpose of this study was to evaluate the clinical efficacy of the intralesional MTX for the treatment of KA in Korean patients. Methods: We retrospectively studied seven patients with KA who received intralesional injection of MTX in our department. The efficacy was evaluated based on the physician assessment. Our review also included the cases of KA treated with intralesional MTX in Korean patients from the previous reports. We then analyzed the therapeutic regimens in the Korean patients by comparing them with the Caucasian patients. Results: We identified 11 cases of Korean KA patients treated with an intralesional MTX, including seven from our institution and four from the Korean literature. Ten of the 11 patients (91%) showed a complete resolution with an intralesional MTX. No adverse events were observed during the treatment and the follow-up periods. No recurrence was found during the follow-up. In therapeutic analysis, the Korean patients required 2 to 7 injections (mean 4.6 injections) to achieve a tumor resolution with the mean time to clearing at 7.6 weeks. Conclusion: Intralesional MTX can be an effective and safe non-operative treatment modality for most Koreans with KA.