Dermatology: Practical and Conceptual Quiz | Dermatol Pract Concept 2015;5(1):14 77 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Below is the answer to the quiz by Dr. Şenel et al presented in the previous issue of Dermatology Practical & Conceptual [2014;4(4):13]. Diagnosis: Kaposi sarcoma. Kaposi sarcoma (KS) was first described by Kaposi in 1872. There are four clinical types of the disease: classic, endemic, epidemic and iatrogenic [1]. Iatrogenic KS develops in patients taking immunosuppressive treatment. Bluish-reddish color- ation is seen in 84% of KS lesions in dermatoscopy. Rainbow pattern and scaly surface are other dermatoscopic features of KS (36% and 15%, respectively) [2]. Multicolored rainbow pattern is the most diagnostic appearance of KS in dermato- scopic evaluation and is associated with vascular lumen-rich histological sub-type [3]. This pattern can be rarely seen in the dermatoscopy of melanoma [4]. Congratulations to Dr. Arina Vashkevich (aavashk@mail. ru), who was the first to send us the correct answer! References 1. Ahmadpoor P. Human herpesvirus-8 and Kaposi sarcoma after kidney transplantation: mechanisms of tumor genesis. Iran J Kid Dis 2009;3(3):121-26. 2. Hu SC, Ke CL, Lee CH, et al. Dermoscopy of Kaposi’s sarcoma: areas exhibiting the multicoloured ‘rainbow pattern’. J Eur Acad Dermatol Venereol 2009;23(10):1128-32. 3. Şenel E. Dermatoscopy of non-melanocytic skin tumors. Indian J Dermatol Venereol Leprol 2011;77(1):16-21; quiz 22. 4. Cheng ST, Ke CL, Lee CH, et al. Rainbow pattern in Kaposi’s sarcoma under polarized dermoscopy: a dermoscopic pathological study. Br J Dermatol 2009;160(4):801-9. What is your diagnosis? A solitary purple papule on the arm—Answer Engin Şenel1, Yasemin Yuyucu Karabulut2 1 Hitit University Faculty of Medicine, Department of Dermatology, Çorum, Turkey 2 Mersin University Faculty of Medicine, Department of Pathology, Mersin, Turkey Citation: Şenel E. Karabulut YY. What is your diagnosis? A solitary papule on the arm Dermatol Pract Concept. 2015;5(1):14. doi: 10.5826/dpc.0501a14 Copyright: ©2015 Şenel et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Corresponding author: Engin Şenel, MD, BBA, Assistant Professor of Dermatology, Hitit University Faculty of Medicine, Department of Dermatology, 19200 Çorum, Turkey. Tel. +90 364 2230300; Fax +90 364 2230323. Email: enginsenel@enginsenel.com mailto:aavashk@mail.ru mailto:aavashk@mail.ru mailto:enginsenel@enginsenel.com