The appearance of comedos in a zone surrounding the scar following roentgen therapy for an epithelioma of the face has recently been observed. The case is the first to be encountered out of several hundred cases of epithelioma treated by a similar technic in the dermatology clinic. The patient, a 63 year old man, had an epithelioma on the cheek (fig., A), which on histologic examination was found to be of the mixed cell type. He was treated with roentgen rays, receiving 2,160 r once each week for three weeks. The site healed within the course of eight weeks, and when examined several weeks later there was an atrophic scar with slight depigmentation, around which blackish horny lesions were arranged in a concentric zone (fig., B). On compression with a comedo extractor, each of the horny plugs was found to be a comedo. In the section of the illustration showing