A 25-year-old man walked into a dermatology clinic in Saudi Arabia with a large, sharply bordered, yellowish plaque spread across his chest. It had been growing slowly for about six months, did not itch or hurt, and would not come off in the shower. His doctors lined up six possible diagnoses, took a punch biopsy, and then wiped the area with a 70% isopropyl alcohol pad.
Most of it came off on the spot.
