| Light micrograph of a section through human skin with Bowen's disease, a pre-invasive form of squamous cell skin cancer. The cancer cells are confined to the epidermis, the outer layer of the skin (purple, centre), where they proliferate and form circular patterns called keratin pearls - a common characteristic of squamous cell carcinomas. The cornified surface layer of the skin (dark pink, top) displays parakeratosis, thickening of the skin, which causes red scaly plaques. Bowen's disease is caused by exposure to sunlight, some chemicals and a strain of the human papilloma virus. The plaques are most common on the trunks, arms, legs and genitals. Treatment is with removal of the plaques by freezing, chemotherapy or surgery, and once removed this disorder is unlikely to recur. Haematoxylin-eosin saffron (HES) stain. Magnification: x100 at 24x36 mm size. |