Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2023;13(1):e2023051 1 An Incidental Finding of Pili-Multi Gemini of the Back Anna Wolinska1, Paula Beatty1, Gregg Murray3, Helen Barrett2, Marina O’ Kane1 1 Department of Dermatology, Beaumont Hospital, Dublin, Ireland 2 Department of Histopathology, Beaumont Hospital, Dublin, Ireland 3 Department of Dermatology, Our Lady of Lourdes Hospital, County Louth, Drogheda, Ireland Citation: Wolinska A, Beatty P, Murray G, Barrett HL, O’ Kane M. An Incidental Finding of Pili-Multi Gemini of the Back. Dermatol Pract Concept. 2023;13(1):e2023051. DOI: https://doi.org/10.5826/dpc.1301a51 Accepted: June 11, 2022; Published: January 2023 Copyright: ©2023 Wolinska 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: Anna Wolinska, Department of Dermatology, Beaumont Hospital, Dublin, Ireland. E-mail: annawolinska@alumnircsi.com Case Presentation A 57-year-old man presented with a blue, pigmented patch across the left upper back. This was clinically consistent with nevus of Ito (Figure 1A). On closer inspection with dermos- copy short, dark, tufted hairs were identified which were widespread across the entire back. Multiple hairs measuring < 1 mm arose from each follicular opening (Figure 1B). This finding was isolated to the back. There was no history of prior hair removal to otherwise explain this appearance. A clinical diagnosis of widespread pili multigemini was made. Skin punch biopsy was performed which confirmed the clinical diagnosis. Treatment was not indicated as the patient was asymptomatic at time of diagnosis. Teaching Point Pili multigemini is an unusual hair follicle dysplasia, charac- terized by clusters of shafts that emerge from a single follicle. Folliculitis may also be present. Diagnosis is clinical. Dermos- copy or trichoscopy is helpful for visualizing multiple hairs emerging from the same follicular opening. Electron micros- copy shows multiple distorted hair shafts within a common root sheath. Treatment with permanent, laser ablative tech- niques can be considered for cosmesis. It is rarely described in the literature due to under-reporting in clinical practice and is most commonly found in male facial hair [1,2]. Dermatologists should be vigilant for pathology that may be hidden within concomitant skin changes and this case 2 Image Letter | Dermatol Pract Concept. 2023;13(1):e2023051 emphasizes the importance of thorough full skin examination enhanced by the use of dermoscopy. It raises the discussion of whether pili multigemini represents a true, rare phenome- non or underdiagnosis due to its asymptomatic nature. References 1. Ciudad-Blanco C, Heffernan J, Montero E et al. Extensive pili multigemini over the back. Int J Trichology. 2014;6(4):180-181. DOI: 10.4103/0974-7753.142871. PMID: 25368477; PMCID: PMC4212297. 2. Lester L, Venditti C. The prevalence of pili multigemini. Br J Dermatol. 2007;156(6):1362-1362. DOI: 10.1111/j.1365- 2133.2007.07868. MID: 17441959. Figure 1. (A) 15 cm blue pigmented patch distributed across the left upper back with visible widespread dark, follicular changes. (B) Dermoscopy demonstrating multiple 0.5mm-1mm tufted hairs arising from within each follicular opening.