Intralesional methotrexate for keratoacanthoma of the nose

A 56-year-old woman developed a nodule on her nose. A shave biopsy of the enlarging lesion was performed after 2 weeks and showed a keratoacanthoma. During the subsequent 4 weeks, the lesion continued to grow rapidly, and she was referred for excision of the lesion using the Mohs microscopically controlled technique. A tender 10x12 mm (120 mm2) erythematous nodule with a keratin-filled central umbilication was present on her left nasal ala (Figure 1). Treatment options were discussed. The left nasal ala was locally anesthetized with 1% lidocaine with 1:100,000 epinephrine and the keratoacanthoma was circumferentially infiltrated with 10 mg of methotrexate (0.8 mL of 12.5 mg/mL methotrexate) using a 30-gauge needle. The total amount of methotrexate injected was divided among several injection sites: the peripheral shoulder of the lesion (such that there was blanching of the entire rim) and under the center of the lesion at a depth clinically judged to be the deepest area of involvement. Within the next 7 days, the tumor began to decrease in size and ulcerate centrally. Examination 2 weeks after the initial injection showed a 71% reduction in the area of the tumor, which now measured 35 mm2 (7.0x5.0 mm). The tumor was injected in a similar manner as before with 5 mg of methotrexate. After another 2 weeks, the tumor had continued to shrink. It was flat without nodularity and measured 12 mm2 (4.0x3.0 mm); the tumor area was 66% less than 2 weeks earlier and 90% less than its original size. The residual tumor was again injected with 4.5 mg of methotrexate. There was complete clinical involution of the tumor when the patient returned for evaluation 6 weeks after her initial injection of methotrexate (Figure 2). A biopsy of the lesional area to confirm histologic resolution of the keratoacanthoma was not performed since there was no visible residual tumor. Periodic follow-up examination has been performed and there has been no subsequent recurrence of the keratoacanthoma.