The lesions represent areas of squamous cell carcinoma (SCC) in-situ - that is, SCC contained within the epidermis and not spread beyond the basement membrane. If left untreated, invasive SCC may result. Management options include cryotherapy, topical chemotherapeutic agents, curettage, excision, lasers, photodynamic therapy and radiotherapy, amongst others. There is no good evidence that any one particular method is superior.
They are often asymptomatic and present with a persistent reddish patch of skin with crusting or scaling. Patients are usually > 60years, commoner in females with 75% of lesions found on the leg. Sun exposure is the major aetiological factor.