==== Front Cureus Cureus 2168-8184 Cureus 2168-8184 Cureus Palo Alto (CA) 10.7759/cureus.39909 Dermatology Atypical Pediatric Presentation of Pilomatricoma Muacevic Alexander Adler John R Mohr Cassandra 1 Tschen Jaime 2 1 Dermatology, McGovern Medical School, Houston, USA 2 Dermatology, St. Joseph Dermatopathology, Houston, USA Cassandra Mohr cassandramohr@utexas.edu 3 6 2023 6 2023 15 6 e399092 6 2023 Copyright © 2023, Mohr et al. 2023 Mohr et al. https://creativecommons.org/licenses/by/3.0/ 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. This article is available from https://www.cureus.com/articles/139233-atypical-pediatric-presentation-of-pilomatricoma Pilomatricomas are uncommon, benign tumors of the hair follicle, which are often misdiagnosed upon initial inspection. Here we describe the case of a 4-year-old boy who presented with a persistent draining tumor on the left side of his neck for approximately two years. The tumor was originally misdiagnosed as scrofuloderma but, eventually, our patient’s pilomatricoma was identified with biopsy and successfully treated with elliptical excision. We discuss the importance of considering pilomatricoma in the differential diagnosis. pediatric tumor head and neck tumors diagnosis delay scrofuloderma pilomatricoma ==== Body pmcIntroduction Pilomatricomas are frequently misdiagnosed, benign tumors that derive from the hair follicle [1]. They most commonly present on the head and neck as a firm, solitary, slow-growing tumor with a normal to pearly white dermis [2]. The overlying skin may have a blue or red discoloration. A perforating pilomatricoma is a rare clinical variant, presenting as an ulcer or horn-like, crusted nodule [3-5]. Pilomatricomas are also often referred to as calcifying epitheliomas of Malherbe due to frequent calcification of the tumor [6]. On histology, perforating pilomatricomas show transepidermal elimination of the tumor [7]. Though the exact pathophysiology remains unknown, a genetic link has been described in previous studies [8,9]. A mutation in exon 3 of the B-catenin gene involved in hair follicle differentiation has been proposed as a possible mechanism. Additionally, it has been established that the prevalence of pilomatricomas in patients with myotonic dystrophy is higher than in the general population [10-12]. Patients with myotonic dystrophy are also more likely to have multiple pilomatricomas and positive family history. Classic pilomatricomas have a bimodal distribution, presenting typically in children or the elderly. Perforating pilomatricomas, however, are much more common in the elderly [13]. Pilomatricomas typically present in Caucasians and have a slightly higher prevalence among females. When treatment is indicated, surgical excision is the first-line method and commonly results in complete resolution of the lesion. In the approximately 5% of cases that do recur, incomplete resection is the usual culprit. Case presentation A 4-year-old boy presented with a draining tumor on the left side of his neck, located posteriorly and retroauricularly. The tumor had persisted for the past two years. Several months prior to presentation, the lesion had ruptured the surface and was diagnosed as cutaneous tuberculosis (scrofuloderma). The patient took rifampin and doxycycline as prescribed for several months without any noticeable improvement. On physical exam, a 1.3 cm crusted draining tumor was appreciated on the left posterior neck (Figures 1-2).  Figure 1 Ulcerated tumor in the patient's neck (distant view) Figure 2 Ulcerated tumor in the patient's neck (closer view) Upon injection of the anesthetic for excisional biopsy, a white chalky substance was drained. A smear of the material performed prior to the biopsy showed epithelial cells with a few ghost cells (Figure 3). Figure 3 Smear of chalky material obtained after infiltration of anesthesia; characteristic ghost cells (arrows); hematoxylin and eosin 200x The elliptical excision was completed without any complications. Final histopathology report of the epidermal channel described epithelial and ghost cells characteristic of a perforating pilomatricoma (Figures 4-5). A sinus containing tumor fragments with hemorrhage and both acute and chronic inflammation was seen. Moderate peripheral acanthosis was visualized at the opening of the sinus. The tumor showed no cytologic atypicalities and a small nasal oír (matricial) component, with the bulk of the tumor composed of sheets of ghost cells. Figure 4 Perforating tumor (arrows) with disrupted epidermis; hematoxylin and eosin 10x Orientation: top of image is on the left. Figure 5 Characteristic ghost cells (circled) in tumor nest; hematoxylin and eosin 40x On follow-up at three months, the surgical site had healed without any evidence of recurrence. Discussion Pilomatricoma was first described in 1880 by Malherbe and Chenantais [14]. It was originally suspected to originate from the sebaceous glands [15]. Over time, it was discovered that these benign tumors originated from the hair follicle, and the term 'pilomatricoma' came into use through Jones and Campbell in 1969 [16]. These cutaneous, firm lesions are often mistaken for similar yet more common lesions such as keratoacanthomas, neurofibromas, chondromas, and fibroxanthomas [1]. Our case of a rare clinical variant, perforating pilomatricoma, was incorrectly identified as scrofuloderma. This was likely due to the unique clinical characteristics of the perforating pilomatricoma involving tumor drainage and ulceration. The clinical differential diagnosis for a perforating pilomatricoma includes pyogenic granuloma, arteriovenous malformation, epidermal inclusion cyst, and soft tissue sarcomas [17]. Scrofuloderma, like pilomatricoma, often presents as a painless, subcutaneous, slow-growing lesion [18]. Scrofulodermas also typically present with purulent discharge which was consistent with our patient’s presentation. Scrofuloderma is diagnosed with a skin biopsy, showing multinucleated giant cells, caseous necrosis, and mixed inflammatory cells. In our case, histopathology was consistent with a perforating pilomatricoma, presenting with islands of epithelial cells, ghost cells, and basophilic cells [19]. Our case demonstrates the importance of clinicopathological correlations. Lesions exhibiting ghost cells include pilomatricomas, craniopharyngiomas, calcifying cystic odontogenic tumors, and odontomas. However, the tumor location would only be characteristic of a pilomatricoma or pilomatrix carcinoma. Further, the head and neck location is characteristic of many benign and malignant tumors. However, the ghost cells and draining sinus narrowed the diagnosis to perforating pilomatricoma.  The most reliable diagnostic modality for pilomatricomas remains biopsy with pathologic evaluation. Once diagnosed, pilomatricomas have an excellent prognosis following complete excision. No other treatment modalities provide a definitive diagnosis and cure. The recurrence rate after excision has been reported to be approximately 2.6% [20]. Correct diagnosis and early intervention of pilomatricomas are important to avoid potential transformation into a pilomatrix carcinoma. This transformation, however, is much more likely to occur on the head and neck of middle age to elderly patients and occurs very rarely in children. Nevertheless, the rate of malignant transformation of pilomatricomas is difficult to establish due to the difficulty in distinguishing the malignant transformation of a benign pilomatricoma from a de novo pilomatrix carcinoma. Conclusions Pilomatricomas are rare, benign lesions that typically present on the head and neck region of children or the elderly. Our case was a rare perforating type which, likely due to the tumor’s ulcerating characteristics and the fact that our patient was not in the typical age category for this lesion, was improperly diagnosed as scrofuloderma. A pilomatricoma should be in the differential diagnosis when presented with a firm, solitary, slow-growing tumor in the head and neck of a child or elderly adult. Ulceration and drainage of the lesion can be indicative of the rare perforating clinical variant even among the pediatric population. To ensure diagnostic accuracy and proper management of these lesions, it is best to perform a biopsy for pathological evaluation. Once diagnosed, pilomatricomas often resolve completely with surgical excision, as described in this case. Human Ethics Consent was obtained or waived by all participants in this study The authors have declared that no competing interests exist. ==== Refs References 1 Pilomatricoma: an unusual dermatologic neoplasm Hawaii J Med Public Health DeRosa DC Lin-Hurtubise K 282 286 71 2012 https://pubmed.ncbi.nlm.nih.gov/23115748/ 23115748 2 Pilomatricoma of the head and neck: a retrospective review of 179 cases Arch Otolaryngol Head Neck Surg Lan M Lan M Ho C Li W Lin C 1327 1330 129 2003 https://jamanetwork.com/journals/jamaotolaryngology/fullarticle/484046 14676160 3 Pilomatricoma of the head and neck: a retrospective review of 179 cases Arch Otolaryngol Head Neck Surg Lan MY Lan MC Ho CY Li WY Lin CZ 1327 1330 129 2003 14676160 4 Proliferating pilomatricoma: a histopathologic simulator of matrical carcinoma J Cutan Pathol Kaddu S Soyer HP Wolf IH Kerl H 228 234 24 1997 9138114 5 Proliferating pilomatricoma--case report An Bras Dermatol Kondo RN Pontello Junior R Belinetti FM Cilião C Vasconcellos VR Grimaldi DM 94 96 90 2015 26312685 6 Pilomatrixoma (calcifying epithelioma) Arch Dermatol Forbis R Helwig EB 606 618 83 1961 13700704 7 A clinical review of 209 pilomatricomas J Am Acad Dermatol Julian CG Bowers PW 191 195 39 1998 9704827 8 Pilomatrixoma masquerading as giant chalazion Ophthalmology Lloyd M Eagle RC Wasserman BN 1936 125 2018 30454715 9 Surgical excision of pilomatrixoma of the head and neck: a retrospective review of 26 cases Ear Nose Throat J Thomas RW Perkins JA Ruegemer JL Munaretto JA 544 546 78 1999 https://pubmed.ncbi.nlm.nih.gov/10485145/ 10 Pilomatricomas associated with myotonic dystrophy Arch Dermatol Chiaramonti A Gilgor RS 1363 1365 114 1978 686751 11 Syndromes associated with multiple pilomatricomas: when should clinicians be concerned? Pediatr Dermatol Ciriacks K Knabel D Waite MB 9 17 37 2020 31618803 12 Mutation analysis of multiple pilomatricomas in a patient with myotonic dystrophy type 1 suggests a DM1-associated hypermutation phenotype PLoS One Rübben A Wahl RU Eggermann T Dahl E Ortiz-Brüchle N Cacchi C 0 15 2020 13 Proliferating pilomatricoma in a 9-year-old girl Pediatr Dermatol McCormack L Trivedi A Lal K Amano S Elaba ZR McIntyre J Wiss K 1187 1188 37 2020 32985708 14 Note sur l'epithelioma calcifie des glandes sebaces Progr Med Malherbe A Chenantais J 826 828 8 1880 15 De l'epithélioma calcifié: étude histologique Ann Dermatol Syphilol Dubreuilh W Cazenave E 257 268 3 1922 16 Pilomatricoma can differentiate not only towards hair matrix and hair cortex, but also follicular infundibulum, outer root sheath and hair bulge Exp Dermatol Kurokawa I Yamanaka K Senba Y Sugisaki H Tsubura A Kimura T Mizutani H 734 737 18 2009 19469893 17 Six cases of perforating pilomatricoma: anetodermic changes with expression of matrix metalloproteinases J Dermatol Watabe D Mori S Akasaka T Motegi SI Ishikawa O Amano H 82 85 47 2020 31677179 18 Scrofuloderma: a diagnostic challenge An Bras Dermatol Mello RB Vale EC Baeta IG 102 104 94 2019 30726475 19 Cytopathological findings of proliferating pilomatricoma misdiagnosed as a malignant parotid gland tumor Diagn Pathol Kurose N Yamashita M Nakano M 65 13 2018 30153836 20 A new case of the pilomatrixoma rare in the preauricular region and review of series of cases Oral Maxillofac Surg Pinheiro TN Fayad FT Arantes P Benetti F Guimarães G Cintra LT 483 488 22 2018 30284072