Basal cell carcinoma, false colored section. Cells within the tumour are purple and have an abnormal arrangement. The skin surface is at top (red). When I made my visit to a very good Mohs clinic in town (not as a patient), there was an elderly gentleman with a horn on his head. By which I mean he had a grey-black tumor the size of a very large egg on the top of his head which was actually shaped like a broken horn. He had spent years hiding it under a hat and had no family and friends to push him to see a doctor about it until that day. When the doctor cut into it, the massive amount of necrotic tissue underneath stunk so badly, it knocked out the nurse in the room. It was… well, it was something else.