While there have been several reports about the development of malignant neoplasms in porokeratosis of Mibelli and porokeratosis plantaris, palmaris et disseminata, only one case of squamous cell carcinoma in disseminated superficial actinic porokeratosis (DSAP) has been documented. A review is presented of the variants of porokeratosis that have so far been described in the literature as well as the differential diagnosis, genetic aspects and therapy of DSAP. The first case of DSAP with Bowen's disease is presented.