A 51-year-old man presented with a 12-year history of an expanding, irritable rash on his buttocks, groin and scrotum. He gradually developed erythematous, annular plaques with ridged borders and depressed centres. He also had a verruciform eruption in his perianal area. A clinical diagnosis of porokeratosis confined to the genitogluteal area was confirmed histopathologically. Oral acitretin resulted in symptomatic and cosmetic improvement. He continues to be followed up to evaluate treatment outcomes.