Photoletter to the editor: Pityriasis Rotunda.

Pityriasis rotunda is described as persistent, large, sharply defined circular patches of dry ichthyosiform scaling with no inflammatory changes. Pityriasis rotunda may be associated with systemic diseases (eg. hepatocellular carcinoma). We report a case of pityriasis rotunda in a 19-year-old, otherwise healthy male. The condition started one year prior to his referral. Lesions were distributed over the trunk and upper extremities. Histopathological examination revealed hyperkeratosis, absent granular layer, pigmented basal layer, pigmentary incontinence and perivascular lymphocytic infiltrate. PAS staining for fungi was negative. Treatment of pityriasis rotunda in this case was challenging. When there's an underlying disease, successful treatment of the original disease leads to clearance of pityriasis rotunda lesions.