Hidden Pictures of Kaposi's Sarcoma in Psoriatic Lesions: A Diagnostic Challenge

Kaposi's sarcoma is a multifocal proliferative vascular tumor involving the skin and other organ and psoriasis is a chronic cutaneous disease with papules and plaques with white scale. Development of Kaposi's sarcoma in psoriasis patients has been reported rarely. A 71-year-old man presented with multiple brownish to violaceous plaques on both feet and arms which were found 4 months ago. The biopsy confirmed Kaposi's sarcoma. The patient was diagnosed with psoriasis vulgaris 10 years ago and Kaposi's sarcoma lesions developed between psoriatic plaques. We herein report a rare case of simultaneous occurrence of Kaposi's sarcoma and psoriasis vulgaris which need quite different treatment.