To the Editor.—
Isolated keratoacanthomas can be very destructive before involution finally occurs. The problem of treatment and possible malignancy presents itself in such instances when the lesion does not regress, as most keratoacanthomas do. In two cases, isolated destructive keratoacanthomas on the nose responded rapidly to treatment with methotrexate.
Report of Cases
Case 1.—
A 69-year-old man had a typical keratoacanthoma involving the right side of the nose and extending on to the mucous membranes (Fig 1). The lesion appeared about April or May 1972 and was noted during a routine office visit regarding follow-up of several previously-treated areas of skin cancer on the face.When seen initially in June 1972 (approximately one month after onset), the lesion was 10 mm in size; a biopsy specimen was taken. On two subsequent occasions, biopsies were performed to rule out the presence of a malignant tumor. All three cutaneous