Dermatology: Practical and Conceptual 24 Letter | Dermatol Pract Concept 2019;9(1):7 Dermatology Practical & Conceptual Introduction Osteoma cutis is a benign uncommon tumor characterized by the presence of bone tissue in dermis or hypodermis. It is classified as primary when the bone tissue originates from the skin without a preexisting lesion and secondary when there has been a previous inflammatory, traumatic, cicatricial, or neoplastic process [1]. We report a case of primary plaque osteoma cutis. Case Presentation A 27-year-old woman presented with a 9-year history of slowly enlarging, hard lesions on her scalp, forehead, and nose, which created 2 irregular plaques that were painful on palpation, both with erythema in their periphery. The plaques measured approximately 1 to 5 mm in diameter (Figure 1). Dermoscopy showed concentric white and yellowish structures with an erythematous border area (Figure 2). At age 18 the patient noted 2 small scalp lesions, hard and painful, that increased in number and size over the years. There was no personal or family history relevant to her con- dition. Her otorhinolaryngologist reported a slight visible central nasal pyramid with slight irregularities. Histopathology showed a stratum corneum with basket- weave pattern, irregular acanthosis and hyperpigmentation of basal layer, superficial, and middle dermis with dilated blood vessels, atrophic hair follicles, no alteration of sweat glands, and a mild perivascular inflammatory lymphocytic infiltrate. The subcutaneous cellular tissue contained a cluster of mature bone tissue with blood vessels and connective tissue. Bone trabeculae had osteocytes (Figure 3). The simple lateral skull and contrast inversion radio- graph showed punctiform images in the skin and subcutane- Dermoscopic and Histopathological Findings in Osteoma Cutis Involving the Face and Scalp Marina Romero Navarrete1, María-Elisa Vega Memije2, Roberto Arenas Guzmán3, Aureliano Castillo Solana4, Gloria E. Reyes López5, Julieta Ruiz Esmenjaud6 1 Dermatology, Hospital General de Acapulco, Secretaría de Salud, Guerrero, Mexico 2 Dermatopathology, Hospital General Dr. Manuel Gea González, Ciudad de Mexico, Mexico 3 Mycology, Hospital General Dr. Manuel Gea González, Ciudad de Mexico, Mexico 4 Epidemiology, Hospital General de Acapulco, Secretaría de Salud, Guerrero, Mexico 5 Otorhinolaryngology, Hospital General de Acapulco, Secretaría de Salud, Guerrero, Mexico 6 Dermatology, Private Practice, Ciudad de México, Mexico Key words: plaque-like osteoma cutis, primary osteoma cutis, secondary osteoma cutis Citation: Romero Navarrete M, Vega Memije M-E, Arenas Guzmán R, Castillo Solana A, Reyes López GE, Ruiz Esmenjaud J. Dermoscopic and histopathological findings in osteoma cutis involving the face and scalp. Dermatol Pract Concept. 2019;9(1):24-27. DOI: https://doi. org/10.5826/dpc.0901a07 Published: January 31, 2019 Copyright: ©2019 Romero Navarrete 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. Authorship statement: All authors have contributed significantly to this publication. Corresponding author: Marina Romero Navarrete, De la Nao 1809-501 Fraccionamiento La Bocana, Acapulco, Guerrero, México, 39670. Email: marinaromero@live.com.mx Letter | Dermatol Pract Concept 2019;9(1):7 25 ous cellular tissue of the frontal region and nasal pyramid (Figure 4A,B). Laboratory values such as thyroid and lipid profile, blood chemistry, and serum calcium and phosphorus levels were within normal ranges. Discussion Osteoma cutis, first described by Wilkens in 1858, is a benign tumor of bone in the dermis or hypodermis [1]. It is classi- fied as primary or secondary. The primary forms represent 14%-15% of all cutaneous ossifications and can be present in association with Albright hereditary osteodystrophy, pro- gressive ossification, fibrodysplasia, or progressive osseous heteroplasia, as well as isolated, osteoma, generalized or multiple facial miliaria and plaques; and occasionally they present with transepidermal bone elimination. Secondary forms have a previous trauma, infection, inflammation, or neoplasia [1,2]. The term osteoma cutis in plaque was given by Worret and Burgdorf in 1978 [3]. This entity can be congenital or be present in the first year of life. It is associated with nei- ther metabolic calcium nor phosphorus alteration, nor with previous trauma or infections. It is composed of one or more plaques of bone tissue. Figure 1. Clinical features: Plaque-like tumor on the patient’s scalp, forehead, and nose. [Copyright: ©2019 Romero Navarrete et al.] Figure 2. Dermoscopic image: Well-limited, concentric structures in linear arrangement with an erythematous and nacreous pink border. [Copyright: ©2019 Romero Navarrete et al.] Figure 3. Histopathology: Clusters of mature bone and bone trabec- ulae with osteocytes, blood vessels, and connective tissue (hematox- ylin and eosin, 40×). [Copyright: ©2019 Romero Navarrete et al.] Figure 4. X-ray: Forehead and nasal pyramid with punctiform le- sions in the skin and subcutaneous cellular tissue. [Copyright: ©2019 Romero Navarrete et al.] 26 Letter | Dermatol Pract Concept 2019;9(1):7 We searched PubMed using the key words osteoma cutis, primary osteoma cutis, plaque-like osteoma cutis, acquired plate-like, plate-like osteoma cutis, and primary osteoma cutis. We found 20 publications concerning primary osteoma cutis [1,2], and with our report there are 21 (Table 1). Previous reports found 57% of osteoma cutis occurring in males and 43% in females, with an age range from 10 to 77 years, median 37.8. Our patient had the most frequently found topogra- phy, with clinical features similar to those of previously Osteoma cutis is also used to name similar lesions that are acquired after the first year of life [1]. Its pathogenesis is unknown, and it has been related to the abnormal migra- tion of osteoblast to the skin or a metaplasia of fibroblast to osteoblasts. The case described in this report corresponds to a primary plaque osteoma cutis in an adult woman, with 9 years of evo- lution without reported abnormality in calcium, phosphorus, or any previous trauma or infection. Histopathology showed mature bone cluster in the subcutaneous cellular tissue. Table 1. Publications Describing Plaque-Like Osteoma Cutis: 1985-2017 Author Year Sex Age at Onset (years) Topography Histo­ pathology Dermo­ scopy Evolution (years) Transepidermal Elimination of Bone Katz M et al 1985 F 24 Thorax Yes No 2 No Cottoni F et al 1993 M 31 Forehead Yes No 20 Yes Henrich DE et al 1997 F 69 Scalp Yes No 15 Yes Fazeli P et al 1999 F 66 Thigh, knee Yes No 30 Yes Boschert MT et al 2000 M 77 Hand Yes No 5 No Grandhe N et al 2004 M 50 Scalp Yes No 1 Yes Douri T et al 2006 F 25 Scalp Yes No N/A No Ayavini NAM et al 2006 F 20 Forehead, parietal region Yes No 4 No Cohen PR et al 2007 M 48 Temporal region Yes No Childhood No Haro R et al 2009 M 35 Scalp, forehead, cheek Yes No 14 Yes Aneiros FJ et al 2010 M 25 Forehead Yes No 18 months No Salhi A et al 2010 M 22 Postauricular Yes No 18 months No Vashi N et al 2011 M 50 Scalp, cheek, thorax, thighs Yes No 31 No Wu M et al 2011 M 40 Scalp, nose, thorax, lower extremities Yes No 13 No Talsania N et al 2011 M 25 Scalp Yes No Birth No Orme CM et al 2014 M 53 Scalp Yes No Childhood No Ma HJ et al 2014 F 25 Parietal region, forehead Yes No 5 No Coutinho I et al 2014 F 10 Parietal region Yes No 9 No Swaroop MR et al 2016 M 28 Scalp Yes No 4 No Moreira AG et al 2017 F 44 Scalp, forehead Yes Yes 20 No Romero Navarrete M et ala 2019 F 18 Scalp, forehead, nose Yes Yes 9 No a Our case. Letter | Dermatol Pract Concept 2019;9(1):7 27 uncommon entity and our case is the second one that includes dermoscopic findings. References 1. Haro R, Revelles JM, Angulo J, et al. Plaque-like osteoma cutis with transepidermal elimination. J Cutan Pathol. 2009;36(5):591-593. 2. Moreira AG, Mastrangelo MFE, Carvalho QD, Cuzzi T, Canedo de MT, Raso BP. Primary isolated osteoma cutis on the face. Dermatol Online J. 2017;23(4):1-4. 3. Worret WI, Burgdorf W. Congenital plaque-like osteoma of the skin in an infant [in German]. Hautzart. 1978;29(1):590-596. reported cases; it is the second case described with dermo- scopic findings [1,2]. Previously reported treatments include surgery in 40% of cases [1,2]. One patient was treated with 0.025% retinoic acid [2]. Two cases with follow-up at 6 months and 2 years reported no new lesions or recurrences [1,2]. Conclusions We report the first primary plaque-like osteoma cutis case in Mexico with histopathological correlation. This is an