Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2023;13(2):e2023091 1 Congenital Multiple Nevoid Hypertrichosis Nicola Lippolis1, Alex Curti2, Caterina Longo1,2, Vito Di Lernia3 1 Centro Oncologico ad Alta Tecnologia Diagnostica-Dermatologia, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy 2 Dermatology Department, University of Modena & Reggio Emilia, Modena, Italy 3 Dermatology Unit, Arcispedale Santa Maria Nuova, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy Citation: Lippolis N, Curti A, Longo A, Di Lernia V. Congenital Multiple Nevoid Hypertrichosis. Dermatol Pract Concept. 2023;13(2):e2023091. DOI: https://doi.org/10.5826/dpc.1302a91 Accepted: August 17, 2022; Published: April 2023 Copyright: ©2023 Lippolis 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: Vito Di Lernia, Dermatology Unit, Arcispedale Santa Maria Nuova, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy. E-mail: vito.dilernia@ausl.re.it Case Presentation A 3-month-old male infant of Georgian origin was brought for evaluation of three congenital, well-demarcated patches characterized by dark, terminal hairs on the sacral-lumbar region and right lower limb (Figure 1, A and B). On phys- ical examination, the patches had coarse hair of abnormal length. No changes in the underlying skin were found. Der- moscopy did not show brown pigmentation or pigment net- work. The pseudo-Darier sign was not detected on palpation. There was no relevant family history. The child had followed normal developmental milestones. A multidisciplinary pedi- atric consultation did not disclose abnormalities. Histology performed on the patient’s back showed only terminal hair without additional relevant epidermal and dermal changes. A diagnosis of nevoid hypertrichosis was made. A magnetic resonance imaging was considered but postponed in absence of clinical issues. At eighteen-month follow-up no additional clinical problems were discovered. Teaching Point Nevoid hypertrichosis is a rare disorder consisting of a solitary, circumscribed area characterized by terminal hair growth on otherwise appearing skin [1]. Multiple patches may be rarely observed. It is predominant in females and arises at birth or shortly after. Hypopigmentation of the un- derlying skin has rarely been reported. Histopathologically, hair follicles are increased in number, but structurally nor- mal, without characteristic or diagnostic features. Nevoid hypertrichosis, in particular when it occurs with multiple patches, may be associated with a series of ocular, cerebral, mental, musculoskeletal, neurological, gastroin- testinal, pulmonary, cardiac abnormalities and with facial dysmorphia [1,2]. Due to heterogeneity in extracutaneous manifestations, specific diagnostic procedures should follow a clinical suspicion. The differential diagnosis includes hypertrichosis cubiti [1]. Patches of unusually long pigmented hair or focal 2 Image Letter | Dermatol Pract Concept. 2023;13(2):e2023091 hypertrichosis may be observed in individuals with Gorlin syndrome and Aicardi syndrome, suggesting a role of the PTCH protein, a negative regulator of pathways involved in hair follicle formation and growth cycle and subjects with Proteus syndrome, due to a possible role of the AKT1 kinase in the hair follicle development [1]. Smooth muscle hamar- toma, Becker nevus, and melanocytic nevi may present an overlying focal hypertrichosis, but epidermal changes are helpful for the diagnosis. References 1. Sotiriadis D, Patsatsi A, Lazaridou E, Sotiriou E, Devliotou-Panagiotidou D. Multiple nevoid hypertrichosis as an iso- lated developmental defect. Pediatr Dermatol. 2009;26(4):436-438. DOI: 10.1111/j.1525-1470.2009.00948.x. PMID: 19689520. 2. Gupta L, Gautam RK, Bharadwaj M. Nevoid hypertrichosis: case report with review of the literature. Int J Trichology. 2011;3(2): 115-117. DOI: 10.4103/0974-7753.90829.PMID: 22223975. PMCID:PMC3250008. Figure 1. Coarse, black hair on the lumbosacral region (A) and right lower limb (B) (lateral aspect of the right thigh and right ankle).