Penile skin cancer. Light micrograph of a section skin from the glans penis showing squamous cell carcinoma in-situ, also known as Erythroplasia of Queyrat. Normal epithelium (bright purple) is at right, with the abnormal epithelium at centre and left. The abnormal cells show enlarged nuclei (dark purple spots), irregular shape and loss of stratification. Symptoms include a red rash and irritation. Treatment includes removal of the affected tissue and chemotherapy.