Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2025;15(1):5089 1 In Vivo Characterization of the Inflammatory Infiltrate in Discoid Lupus Erythematosus (DLE) by Line-Field Confocal Optical Coherence Tomography (LC-OCT) Pierfrancesco Benvenuto1, Vittorio Tancredi1, Andrea Ronchi2, Camila Scharf1, Elisabetta Fulgione1, Elvira Moscarella1 1 Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, University of Campania, Naples, Italy 2 Pathology Unit, Department of Mental and Physical Health and Preventive Medicine, University of Campania, Naples, Italy Key words: Discoid Lupus Erythematosus, LC-OTC Citation: Benvenuto P, Tancredi V, Ronchi A, Scharf C, Fulgione E, Moscarella E. In Vivo Characterization of the Inflammatory Infiltrate in Discoid Lupus Erythematosus (DLE) by Line-Field Confocal Optical Coherence Tomography (LC-OCT). Dermatol Pract Concept. 2025;15(1):5089. DOI: https://doi.org/10.5826/dpc.1501a5089 Accepted: October 9, 2024; Published: January 2025 Copyright: © Benvenuto et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Vittorio Tancredi, MD, Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, University of Campania Luigi Vanvitelli, Via Sergio Pansini, 5, 80131 Naples, Italy. E-mail: tancredivittorio@ymail.com Case Presentation A 37-year-old woman was referred to our department for a large, rapidly growing erythematous plaque of her left nasal sidewall (Figure 1). On dermoscopy, an erythematous back- ground with white-yellow follicular plugs and linear vessels was detected. Line-field confocal optical coherence tomogra- phy (LC-OCT) showed a regular honey-combed epidermis with the presence of multiple follicular plugs on the confocal horizontal plane of visualization. At the junctional level, lin- ear vessels and abundant dendritic and small roundish cells were seen, corresponding to the inflammatory infiltrate. On LC-OCT, a bright infiltrate at the dermoepidermal junc- tion was visible around the plugged follicular infundibula (Figure 1). Histology confirmed the suspected diagnosis of discoid lupus erythematosus (DLE) (Figure 1C). Teaching Point DLE is the most prevalent type of chronic cutaneous lupus erythematosus, an autoimmune and potentially disfiguring skin condition due to the pigmentary sequelae and scars on exposed areas. It most frequently affects women in their third and fourth decades of life. 2 Image Letter | Dermatol Pract Concept. 2025;15(1):5089 References 1. Ruini C, Schuh S, Sattler E, Welzel J. Line-field confocal opti- cal coherence tomography-Practical applications in dermatology and comparison with established imaging methods. Skin Res Technol. 2021 May;27(3):340-352. DOI: 10.1111/srt.12949. Epub 2020 Oct 21. PMID: 33085784. 2. Ürün YG, Ürün M, Danişman MŞ. Dermoscopic Characteris- tics of Cutaneous Lupus Erythematosus According to Subtype, Lesion Location, Lesion Duration, and CLASI Score. Dermatol Pract Concept. 2024 Jan 1;14(1):e2024040. DOI: 10.5826/dpc .1401a40. PMID: 38364410; PMCID: PMC10868886. LC-OCT is a non-invasive optical imaging method which has enabled the combination of high cellular reso- lution with satisfying skin penetration in order to produce in vivo skin images. The integration of LC-OCT in the di- agnostic process is promising, as it could potentially offer a noninvasive means of diagnosing DLE, particularly in cases where biopsy may not be feasible or desirable, such as in frequently exposed areas or in young patients. Further re- search involving more cases of DLE are needed to assess the diagnostic accuracy and utility of LC-OCT in clinical settings [1,2]. Figure 1. (A) A large erythematous plaque on the nasal sidewall in a 37-year-old female. The le- sion had developed in about two months after intense sun exposure during the summer, and the patient herself had treated it with topical antibiotics for several weeks. (B) Dermoscopy revealed an erythematous background with white-yellow follicular plugs and linear vessels. (C) Histological ex- amination showed epidermal atrophy, basal vacuolization, and focal epidermal-dermal detachment; nodular perivascular and periadnexal lymphoid infiltrate in the dermis (H&E stain, original mag- nification × 20). (D) LC-OCT on the confocal horizontal plane of visualization, at the junctional level, linear vessels and abundant dendritic and small roundish cells were seen, corresponding to the inflammatory infiltrate. On the vertical section, a bright infiltrate at the dermoepidermal junction was visible around widened periadnexal spaces.