Acta Dermato-Venereologica 97-4 | Page 39

QUIZ SECTION Erythematous Grouped Papules and Plaque on an Intra-articular Injection Area: A Quiz Young Min CHO, Joong Sun LEE, Dae Won KOO and Kyung Eun JUNG Department of Dermatology, Eulji University Hospital, 95, Dunsanseo-ro, Seo-gu, Daejeon 35233, Korea. E-mail: [email protected] A 43-year-old woman presented with erythematous grouped confluent papules on a plaque on her right shoulder (Fig. 1). The lesion had been present for 2 months and had pro- gressively increased in size, with a grapefruit shape. The patient had a 6-month history of repeated intra-articular injections of triamcinolone acetonide on her right shoulder for controlling pain due to impingement syndrome. She was otherwise healthy and examination did not reveal lymph­ adenopathy or any other cutaneous lesions. Laboratory analyses performed to exclude systemic diseases, such as leukaemia, were negative, including the result of acid-fast bacilli (AFB) stain and tuberculosis (TB) PCR. Histological findings showed a dense, dermal infiltrate of histiocytes with scattered lymphocytes, plasma cells, and neutrophils (Fig. 2). By immunohistochemical analysis, the histiocytes were positive for S-100 protein and CD68, but negative for CD1a (results not shown). The patient was treated with intra-lesional steroid injection therapy once a month and her skin lesions have been gradually improving. Fig. 1. Erythematous grouped confluent papules in a plaque on the right shoulder. Fig. 2. A dense, dermal infiltrate of histiocytes forming emperipolesis (arrow) (haematoxylin and eosin; original magnification ×400). What is your diagnosis? See next page for answer. 550 doi: 10.2340/00015555-2580 Acta Derm Venereol 2017; 97: 550–551 This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2017 Acta Dermato-Venereologica.