Dermatology: Practical and Conceptual Observation | Dermatol Pract Concept 2017;7(4):10 43 DERMATOLOGY PRACTICAL & CONCEPTUAL www.derm101.com Case Report A 69-year-old woman was referred to the Skin Cancer Unit for a solitary pink lesion of the trunk of two months’ dura- tion (Figure 1). Because of the rapid growth of the lesion, the site involved and the age of the patient, a medical consult was requested to rule out malignancy. No relevant medical history was recorded. Dermoscopy and reflectance confocal microscopy (RCM) studies were performed and the lesion was finally biopsied. Dermoscopic examination revealed the predominance of a homogeneous pink color on the background, with prominent shiny whitish structures, arranged in a reticulated pattern (Figure 2). At the periphery, areas of peppering were present. RCM imaging acquired on Vivascope 1500 system (Cali- ber I.D., Andover, MA, USA) showed a regular honeycombed pattern without pagetoid cells at the spinous-granular layer. Only a few dendritic, inflammatory cells and some keratino- cytes with highly refractile cell contours could be detected (Figure 3a). A prominent and widespread inflammatory infiltrate obscuring the dermo-epidermal junction was also present, without melanocytic features (Figure 3b). At the papillary dermis more inflammatory cells with a few mela- nophages could be observed (Figure 3c). Histopathology from the excised lesion showed a promi- nent lichenoid dermal infiltrate with hyperkeratosis, hyper- granulosis and dyskeratinocytes in the epidermis. All findings were in keeping with the final diagnosis of lichen planus (Figure 4). A solitary pink lesion: dermoscopy and RCM features of lichen planus Claudia Pezzini1, Simonetta Piana2, Caterina Longo1,3, Elisa Benati3, Stefania Borsari3, Francesca Specchio3, Elvira Moscarella3 1 Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy 2 Pathology Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy 3 Dermatology and Skin Cancer Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy Key words: lichen planus, dermoscopy, reflectance confocal microscopy, solitary lesion Citation: Pezzini C, Piana S, Longo C, Benati E, Borsari S, Specchio F, Moscarella E. A solitary pink lesion: dermoscopy and RCM features of lichen planus. Dermatol Pract Concept 2017;7(4):43-45. DOI: https://doi.org/10.5826/dpc.0704a10 Received: June 9, 2017; Accepted: September 5, 2017; Published: October 31, 2017 Copyright: ©2017 Pezzini 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: None. Competing interests: The authors have no conflicts of interest to disclose. All authors have contributed significantly to this publication. Corresponding author: Elvira Moscarella, MD, Arcispedale S.Maria Nuova, IRCCS Viale Risorgimento 80, 42100 Reggio Emilia, Italy. Tel. 0522295611. Email: elvira.moscarella@gmail.com We present an unusual onset of cutaneous lichen planus (LP) in a middle-aged patient. The initial presentation as solitary, indolent pink lesion required further investigations to rule out malignancy, es- pecially amelanotic melanoma. Dermoscopy and reflectance confocal microscopy findings were found to be helpful in our case in addressing the correct diagnosis. ABSTRACT mailto:elvira.moscarella@gmail.com 44 Observation | Dermatol Pract Concept 2017;7(4):10 The patient developed multiple similar cutaneous lesions one week later. Systemic steroid therapy led to complete healing. Discussion Reports on alternative applications of dermoscopy in general dermatology are an increasing phenomenon, suggesting its usefulness beyond the oncologic field. This diagnostic tool has allowed the identifications of several skin diseases, both neoplastic and non-neoplastic [1-3]. Regarding inflammatory conditions in dermatology, specific dermoscopic patterns have been well defined for a non-invasive diagnosis [3]. These peculiar clues are somehow easy to identify when the history, distribution and morphology of lesions are evocative for a specific disease. However, things are less straightforward when we face unusual clinical scenarios [4]. Reflectance confocal microscopy, providing a non-invasive imaging at a histologic resolution, has repeatedly proved its reliability in the recognition of different skin diseases, assisting in the iden- tification of difficult to diagnose cases. Solitary pink lesions are often a major challenge for dermatologists, amelanotic melanoma being the diagnosis not to miss. Lichen planus is a relatively common inflammatory dis- order of the skin, often affecting middle-aged patients. In its typical form, pruritic widespread papules develop over weeks. The oral mucosa may be also involved, showing the diag- nostic hallmark of the disease, the Wickham striae [5]. The Figure 1. Clinical picture of the patient. (a) Solitary and asymptomatic pink lesion of the chest of a 69-year-old woman. (b) Close-up of the clinical image. [Copyright: ©2017 Pezzini et al.] Figure 2. Dermoscopy. Homogeneous pink color on the back- ground, with prominent shiny whitish structures, arranged in a re- ticulated pattern. At the periphery areas of peppering are present. [Copyright: ©2017 Pezzini et al.] current case showed rather atypical initial clinical features of LP, simulating a possible malignancy, such as basal cell carcinoma, squamous cell carci- noma or melanoma, at clinical exami- nation. However, the observation on dermoscopy of shiny white structures in a reticular arrangement suggested the diagnostic hypothesis of lichen planus. These structures represent the well- known and characterized dermoscopic counterpart of Wickham striae, which are dermoscopically visible in “non- mucosal” skin and specific for LP [6]. RCM in pinkish lesions has already been applied to discriminate between different skin tumors [7]. Its application in our case proved to be complemen- tary to dermoscopy, revealing “in vivo” the lichenoid infiltrate of LP obscuring the dermo-epidermal junction [8,9], with strong histologic correlation. Even if this confocal feature is not exclusive of LP, and is possibly observed in other interface dermatitides or in lichen planus-like keratosis [9], the final integration of clinical-dermoscopical and confocal inves- tigations led to the correct diagnostic hypothesis. As shown in our case, difficult lesions in everyday clini- cal practice benefit from a synergistic diagnostic approach. Dermoscopic and RCM investigations may support our diagnostic hypothesis, improving its accuracy especially when faced with atypical presentations of common inflammatory skin conditions. Observation | Dermatol Pract Concept 2017;7(4):10 45 References 1. Borsari S, Pampena R, Lallas A, et al. Clinical indications for use of reflectance confocal microscopy for skin cancer diagnosis. JAMA Dermatol. 2016;152:1093-1098. 2. Lallas A, Zalaudek I, Argenziano G, et al. Dermoscopy in general dermatology. Dermatol Clin. 2013;31:679-694. 3. Lallas A, Kyrgidis A, Tzellos TG, et al. Accuracy of dermoscopic criteria for the diagnosis of psoriasis, dermatitis, lichen planus and pityriasis rosea. Br J Dermatol. 2012;166:1198–1205. 4. Papageorgiou C, Apalla Z, Lazaridou E, et al. Atypical case of lichen planus recognized by dermoscopy. Dermatol Pract Concept. 2016;6:39-42. 5. Usatine RP, Tinitigan M. Diagnosis and treatment of lichen planus. Am Fam Physician. 2011;84:53-60. 6. Vázquez-López F, Manjón-Haces JA, Maldonado-Seral C, et al. Dermoscopic features of plaque psoriasis and lichen planus: new observations. Dermatology. 2003;207:151–156. 7. Braga JC, Scope A, Klaz I, et al. The significance of reflectance confocal microscopy in the assessment of solitary pink skin lesions. J Am Acad Dermatol. 2009;61:230-241. 8. Moscarella E, González S, Agozzino M, et al. Pilot study on reflectance confocal microscopy imaging of lichen planus: a real- time, non-invasive aid for clinical diagnosis. J Eur Acad Dermatol Venereol. 2012;26:1258-1265. 9. Agozzino M, González S, Ardigò M. Reflectance confocal mi- croscopy for inflammatory skin diseases. Actas Dermosifiliogr. 2016;107:631-639. Figure 3. RCM imaging. (a) RCM single image taken at the spinous granular layer. A regular honey- combed pattern is visible with a few dendritic inflammatory cells. (b) RCM mosaic image taken at the level of the dermo-epidermal junction with the widespread inflammatory infiltrate obscuring the junc- tion. (c) RCM mosaic at the level of the papillary dermis, in an area of dense inflammatory infiltrate. [Copyright: ©2017 Pezzini et al.] Figure 4. Histological examination. Hyperkeratosis and hypergran- ulosis of the epidermis with scattered dyskeratinocytes are present. In the dermis a dense lichenoid infiltrate obscures the dermo-epi- dermal junction framed by the red square, H&E stain). [Copyright: ©2017 Pezzini et al.]