Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2024;14(2):e2024115 1 Dermoscopic Findings in Skin Infection by Mycobacterium Immunogenum José Magna Aguirre1, Paula Almeida Abarcia1, Pablo Vargas Mora1 1 Dermatology Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile Citation: Magna Aguirre J, Almeida Abarcia P, Vargas Mora P. Dermoscopic Findings in Skin Infection By Mycobacterium Immunogenum. Dermatol Pract Concept. 2024;14(2):e2024115. DOI: https://doi.org/10.5826/dpc.1402a115 Accepted: November 12, 2023; Published: April 2024 Copyright: ©2024 Vargas Mora 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: Pablo Vargas Mora, Dermatology Department, Faculty of Medicine, Universidad de Chile. Dr. Carlos Lorca Tobar 999, Independencia, Santiago, Chile. Email: pablovargas.med@gmail.com Case Presentation A 34-year-old female patient, with no relevant medical his- tory, presented with a painful lesion on her right buttock, accompanied by transparent discharge. This lesion had ap- peared two weeks after receiving an intramuscular injection of a “cell regeneration product” at the injection site. Examina- tion revealed a 2 cm orange nodule with well-defined borders and whitish areas inside, above an 4 cm erythematous- violaceous plaque (Figure 1A). Dermoscopy revealed a yellowish-orange lesion with thick whitish structures in- side and polymorphic vessels  (linear irregular, hairpin and comma vessels). It was surrounded by a milky-red area with poorly defined edges (Figure 1B). Biopsy and culture of the lesion were performed. Mycobacterium immunogenum was isolated, and it was decided to start antibiotics. Teaching Point Dermoscopic findings in skin infections by Mycobacterium tuberculosis and Mycobacterium leprae have already been described in the literature; however, the available informa- tion for atypical mycobacteria is limited to two publications to date [1]. In this case, we observed some dermoscopic findings similar to those described in the literature for other mycobacteria: orange-yellowish areas, whitish structures, and vessels of varying morphology [1]. It is important to consider that the lack of orange areas does not rule out 2 Image Letter | Dermatol Pract Concept. 2024;14(2):e2024115 Figure 1. (A)  2 cm orange nodule with well-defined borders and whitish areas inside, above an approximately 4 cm erythematous-violaceous plaque. (B) Yellowish-orange lesion with well-defined borders, with thick whit- ish structures inside and the presence of polymorphic vessels. granulomatous infection [2]. This is the first case report in the literature to mention dermoscopic findings in a My- cobacterium immunogenum infection. Therefore, a high index of suspicion for mycobacterial infection should be maintained in the presence of these dermoscopic findings, along with a suggestive medical history, which can guide the diagnostic process toward reaching a microbiological diagnosis. References 1. Yao QN, Lu YM, Fei WM, et al. Dermoscopy in Mycobacterium marinum infection and its correlation with clinical and histo- pathological features: a prospective observational study. Clin Exp Dermatol. 2023;48(2):89-95. DOI: 10.1093/ced/llac029 2. Errichetti E. Dermoscopy in general dermatology (non- neoplastic dermatoses): pitfalls and tips. Int J Dermatol. 2021;60(6):653-660. DOI: 10.1111/ijd.15427