Dermatology: Practical and Conceptual Quiz | Dermatol Pract Concept 2016;6(3):1 1 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Clinical presentation An 82-year-old man with Fitzpatrick skin type III presented for the evaluation of a lesion on the left upper back. A scaly pink papule was observed (Figure 1). The differential diagno- sis included squamous cell carcinoma (SCC), actinic keratosis, basal cell carcinoma, and amelanotic melanoma. Dermoscopic appearance On dermoscopy, multiple coiled blood vessels (also termed glo- merular vessels) were scattered across the papule (Figure 2) [1]. A pink papule on the back of an 82-year-old man: an example of the buttonhole sign on reflectance confocal microscopy Syril Keena T. Que1, Naiara Fraga-Braghiroli2, Jane M. Grant-Kels1, Harold S. Rabinovitz2, Margaret Oliviero2, Alon Scope3 1 Department of Dermatology, University of Connecticut Health Center, Farmington, CT, USA 2 Department of Dermatology, University of Miami Miller School of Medicine, Miami, FL, USA 3 Department of Dermatology, Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Citation: Que SKT, Fraga-Braghiroli N, Grant-Kels JM, Rabinovitz HS, Oliviero M, Scope A. A pink papule on the back of an 82-year-old man: an example of the buttonhole sign on reflectance confocal microscopy Dermatol Pract Concept 2016;6(3): doi: 10.5826/dpc.0603a01 Received: December 2, 2015; Accepted: April 25, 2016; Published: July 31, 2016 Copyright: ©2016 Que 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. Funding: Dr. Scope’s confocal microscopy research is supported by the European Commission Marie Curie FP7 Reintegration Grant (PIRG07-GA-2010-268359). Dr. Rabinovitz has received equipment and funding for a fellowship program from Lucid Inc. Competing interests: Dr. Rabinovitz is an investigator in a study coordinated by Lucid Inc, manufacturer of a commercial confocal microscope. The authors have no conflicts of interest to disclose. All authors have contributed significantly to this publication. Corresponding author: Syril Keena Que, MD, University of Connecticut Health Center Department of Dermatology, 21 South Rd, Farmington, CT 06030, USA. Tel. 860. 679.4600. Email: keenaq@gmail.com Figure 1. Squamous cell carcinoma in situ. Scaly pink papule on the left upper back. [Copyright: ©2016 Que et al.] Figure 2. Squamous cell carcinoma in situ. Dermatoscopic image showing dotted and round blood vessels (black arrows) appearing centrally and around the periphery. [Copyright: ©2016 Que et al.] mailto:keenaq@gmail.com 2 Quiz | Dermatol Pract Concept 2016;6(3):1 Discussion A buttonhole sign in the presence of an atypical honeycomb pattern is an RCM clue for SCC. Previous articles have correlated dotted vessels on dermoscopy with sparsely dis- tributed round vessels on RCM [2]. Here we report a new RCM diagnostic clue not previously reported—the presence of numerous round vessels in an SCC in situ with coiled ves- sels. The uniformity, clustered nature, and multitude of these round vessels reflect the way these vessels repeatedly loop through the dermal papillae. This finding is not specific for SCC and can be observed in conditions like psoriasis or clear cell acanthoma, when there are coiled or glomerular vessels seen under dermoscopy. However, in SCC the increased vas- cularity is seen under RCM in conjunction with irregularity of the honeycomb pattern of the spinous and granular layers of the epidermis. References 1. Rishpon A, Kim N, Scope A, et al. Reflectance confocal micros- copy criteria for squamous cell carcinomas and actinic keratoses. Arch Dermatol 2009 Jul;145(7):766-72. PMID: 19620557. DOI: 10.1001/archdermatol.2009.134. 2. Ahlgrimm-Siess V, Cao T, Oliviero M, et al. The vasculature of nonmelanocytic skin tumors on reflectance confocal microscopy: vascular features of squamous cell carcinoma in situ. Arch Der- matol 2011 Feb;147(2):264. PMID: 21339468. DOI: 10.1001/ archdermatol.2010.416. Reflectance confocal microscopy appearance Reflectance confocal microscopy (RCM) at the level of the dermo-epidermal junction shows dermal papillae appear- ing in cross-section as perfect circles, resembling “buttons.” Round blood vessels traverse through the dermal papillae, appearing centrally and around the periphery as “button- holes” (Figure 3). The surrounding epidermis is characterized by an atypical honeycomb pattern consisting of cells with variability in brightness and in the size of nuclei. What is your diagnosis? Diagnosis Histopathology revealed SCC in situ (Figure 4). The “button- holes” seen on RCM correlate with numerous tortuous blood vessels at the dermal papillae of the SCC in situ (Figure 5). Figure 3. Squamous cell carcinoma in situ. At the level of the dermo- epidermal junction, reflectance confocal microscopy reveals round blood vessels (“buttonholes”) traversing the dermal papillae (“but- tons,” red arrows). [Copyright: ©2016 Que et al.] Figure 4. Histopathology reveals full-thickness cytological atypia with mitoses and acantholysis, consistent with squamous cell carci- noma in situ. [Copyright: ©2016 Que et al.] Figure 5. Psoriasis. At the level of the dermo-epidermal junction, reflectance confocal microscopy reveals round blood vessels (“but- tonholes”) traversing the dermal papillae (“”buttons”, red arrows). [Copyright: ©2016 Que et al.]