Terra-firma forme dermatosis on the back of a 33 year old female Hispanic patient. This benign (non-cancerous) condition results in raised brown to black plaques that resemble dirty skin. It is also known as dirty dermatosis, but is not caused by poor hygiene. It is thought to arise from an abnormal keratinisation (thickening) of the skin. The lesions can be removed with alcohol wipes and rarely recur.