Solitary keratoacanthoma developing on an acupuncture site

A 61-year-old woman, who had been treated by acupuncture on the glabellar region due to frontal headache ten days ago, had a rapidly growing tumor on that region. Histopathologically, the tumor was shown to be a central crater filled with eosinophilic keratin and a marginal buttress formed by invagination of the epidermis. According to clinical and histopathological findings, we can easily diagnose our case as solitary keratoacanthoma. As shown in our case, we think that acupuncture should be counted as one of the causative factors in the development of solitary keratoacanthoma.