Bowen disease associated with porokeratosis of Mibelli.

A 73-year-old woman developed Bowen precancerous dermatosis in an area of porokeratosis of Mibelli on her leg. This is the fourth reported case of Bowen disease arising from porokeratosis of Mibelli. The recent literature indicates that porokeratosis of Mibelli may be due to an abnormal clone of cells, predisposing affected individuals to development of malignant neoplasms over the involved areas.