Abstract:  Porokeratosis is a rare disorder of epidermal keratinization that is regarded as a precancerous. Recipients of hematopoietic stem cell transplantation (HSCT) have a greater risk of skin cancer; chronic graft versus host disease (GVHD) is an additional risk factor. A 16-year-old boy who had received HSCT for acute myelogenous leukemia was referred to us for sclerodermoid chronic cutaneous GVHD. Two years later, he developed disseminated porokeratosis with a few atypical lesions. Despite cryotherapy, numerous lesions of porokeratosis recurred rapidly. Acitretin resulted in good clinical response and reduced the rate of onset of new lesions.