Calcifying Acne: An Unusual Extraoral Radiographic Finding

Calcinosis cutis is a condition of accumulation of calcium salts within the dermis leading to the formation of a calcified mass. This complication has been reported in acne vulgaris and other systemic metabolic disorders. This paper presents a rare case of calcinosis cutis in a 14-year-old male which was found at a routine orthodontic assessment.


Introduction
Acne vulgaris (AV) is a benign dermatological condition resulting from overproduction of sebum by the skin's sebaceous glands. e condition commonly occurs in adolescents and young adults. It primarily a ects the face, upper back, and chest, producing two types of lesions, in ammatory lesions and comedones. Physical sequelae of the condition such as scar formation and hyperpigmentation are common, but rarer sequelae such as cutaneous calci cations are infrequently reported in the literature [1,2].
Calcinosis cutis occurs as a result of the deposition of calcium salts in the dermis and subcutaneous tissues. is complication has not only been reported in AV and systemic metabolic disorders such as hyperparathyroidism, infection, or connective tissue disorders but can also occur following trauma to an area of the skin. Calcinosis cutis can be subdivided into 4 groups based on aetiology: dystrophic, metastatic, iatrogenic, and idiopathic [3]. e dystrophic type occurs in patients with normal calcium and phosphate levels but con ned to areas where tissue has been damaged following infection, in ammation, or connective tissue diseases.
is paper presents a case report of dystrophic calcinosis cutis in a 14-year-old male, resulting from in ammatory facial acne.

Case Report
A Caucasian male aged 14 years attending an orthodontic clinic for a routine assessment presented with an incidental radiographic nding. A well-de ned calci ed mass was visible at the apex of the maxillary right permanent canine on the orthopantomogram (OPG) radiograph ( Figure 1).
A lateral cephalometric radiograph showed that this mass was signi cantly superior to the dentition in the antral inferior nasal region ( Figure 2). e mass was a well-de ned spherical lesion, measuring 1.5 by 1 cm with a radiopaque, homogeneous internal structure. It lay superior to the canine fossa and anterior to the maxillary sinus anterior wall. is calci ed mass had not been present on the OPG radiograph taken previously, at age 10 years ( Figure 3).
From the age of 12, it was reported that the patient su ered with facial AV. He attended a consultant dermatologist who treated the condition successfully. e calcied mass was previously assessed at dermatological review. Despite the fact that it was a solitary lesion, it was diagnosed as dystrophic calcinosis cutis. e dermatologist advised no intervention as there was a signi cant risk of facial scarring if surgically removed. e mass was asymptomatic and presented little risk of infection. e patient was placed on annual review with his dermatologist.
Although the mass was palpable and mobile, the patient's dermis was intact and acne-free. e mass was not visible clinically on extraoral examination. Facial pro le and contour were normal. Orthodontically, he presented with a Class III incisor relationship on a Class III skeletal base with crowding in the maxillary arch. Both the patient and his parents were given the option of orthognathic surgery to treat his malocclusion and underlying signi cant skeletal relationship discrepancy. After extensive discussions and reviews with a maxillofacial surgeon, they opted for orthodontic treatment only, namely, alignment of the maxillary arch teeth on a non-extraction basis, followed by permanent retention. e orthodontic treatment was uneventful and successful.

Discussion
Acne vulgaris is a dermatological disease caused by changes in the hair follicle and its associated sebaceous gland, jointly called the pilosebaceous unit. AV a ects approximately 80% of the population between 12 and 25 years of age. It does not display race or gender prevalence di erences [4]. ree factors are required for the development of AV, these being sebum, androgens, and the bacterium Propionibacterium acnes. AV begins with the release of androgens, which in turn leads to the increased production of sebum in the sebaceous glands and intrafollicular hyperkeratosis [4]. e resulting skin lesions can be either comedones or in ammatory in nature.
Comedones are subdivided into blackheads and whiteheads. A blackhead is a comedone which is open to the skin surface allowing the contents to escape. e black colour is due to melanin pigmentation. e whitehead is a closed comedone, which does not allow its contents to escape.
In ammatory lesions arise if the walls of a closed comedone rupture. Lipoid tissue is expressed into the surrounding dermis. is sets up a foreign body in ammatory reaction and coupled with P. acnes leads to infection and the formation of acne lesions including papules, pustules, nodules, and/or cysts [5].
Healing of the AV in ammatory lesions can occur via two processes. Firstly, healing by brous tissue can lead to scar formation, while secondly, the epidermis portion of the remaining comedone walls sends out sheaths of epithelium to encapsulate any in ammatory material. e encapsulated mass can become thickened by the evaporation or absorption of uid. is thickened mass, coupled with necrotic tissues, which are produced as part of healing, provides an ideal environment for the formation of calci cations known as calcinosis cutis [4][5][6].
Calcinosis cutis is characterized by abnormal deposits of calcium salts in the dermis and/or hypodermis. It often presents as multiple hard pale plaques, nodules, or papules; however, it can present as a singular lesion also [4,5]. Based on its aetiology, it is divided into 4 subtypes: dystrophic, metastatic, iatrogenic, and idiopathic.
Dystrophic calcinosis cutis occurs in areas of tissue damage secondary to infection, in ammatory processes, connective tissue diseases, or cutaneous neoplasms [7]. It is the most common form of ectopic calci cation and develops around local tissue damage without any alteration to calcium or phosphate metabolism, for example, in AV. In contrast, metastatic calci cation is due to changes in the metabolism of calcium or phosphate, which leads to precipitation of calcium in the skin [3]. Idiopathic calci cation arises without any underlying tissue damage or metabolic disorder, while iatrogenic calci cation is secondary to medical interventions which can damage tissue or lead to disturbances in calcium and phosphate metabolism. An international multicenter cohort study [8] found an overall frequency of calcinosis cutis of 22% in patients with connective tissue diseases; however, there are no speci c data relating to incidence of dystrophic calcinosis cutis in the literature [8].
Dystrophic cutaneous calci cation secondary to longterm acne was rst reported in 1928 by Hopkins [9] and later    Case Reports in Dentistry by Leider [10] who found radiographic evidence of calcinosis cutis in four of six patients with long-term AV. Other medical studies have shown that these calci cations can be identi ed in as many as half of all cases of long-term AV (i.e., 7 years or more) [11,12]. Interestingly, the patient in our case report had only su ered with AV for 2 years. In addition, it is the only reported case of dystrophic calcinosis cutis reported in the orthodontic setting. Diagnosis of dystrophic calcinosis cutis is based on serological investigations, suitable imaging, and biopsy if required [1,2,4]. Histopathological examination would show a focus of a well-circumscribed, round, basophilic substance, which would stain black with the Von Kossa stain. It may be located in the upper dermis, surrounded by thick collagen bers and sometimes by epithelioid and multinucleated giant cells [13].
Due to its radiopaque nature, dystrophic calcinosis cutis can be visualized on plain lm radiographs; however, other useful modalities which could have been used include cone beam computed tomography (CBCT) and ultrasound [1]. ese imaging modalities can be used either singularly or in combination to improve localization; however, if CBCT is to be used, one must consider the e ects of a higher radiation dose [1,2]. In addition to serological assessment for connective tissue disease, full biochemical assessment is required to exclude any abnormality of systemic calcium homeostasis-this should include serum calcium, phosphate, alkaline phosphatase, vitamin D, and parathyroid hormone (PTH) estimation [14]. Di erential diagnoses include osteoma cutis, calci ed lymph nodes or cysts, and areas of calci ed necrotic materials such as caseous granulomas in tuberculosis. While dystrophic calcinosis cutis results in calci cation of areas in the skin, osteoma cutis causes ossication of the dermis and subcutaneous tissue. It can be deemed that primary ossi cation occurs in the absence of a preexisting cutaneous disorder, while secondary osteoma cutis occurs when bone forms in a preexisting lesion [15].
In cases of di use calcinosis cutis, such as metastatic or iatrogenic, medical management is required to correct the systemic imbalance.
is includes the use of warfarin, bisphosphonates, minocycline, ceftriaxone, diltiazem, aluminium hydroxide, probenecid, intralesional steroids, and intravenous immunoglobulin [14]. For cases of singular lesions, such as that highlighted in our case, surgical treatment is preferred. Methods include surgical excision, curettage, laser therapy, and lithotripsy [16]. Surgical management in this case report was contraindicated, given the risk of facial scarring postoperatively. e mass was asymptomatic and considered at low risk of reinfection. Facial pro le and dermal contour were normal. e location of this calci ed mass would have posed a problem, however, had the patient opted for orthognathic surgery for his Class III malocclusion. As both he and his parents opted for a conservative orthodontic approach, no surgical intervention was necessary, and annual observation of this lesion by his dermatologist continued.

Conclusions
Dystrophic calcinosis cutis can occur as a sequela of longterm AV or alongside underlying metabolic disorders.
Dentists should be aware of this phenomenon, as it can occur in the facial region and may present as an incidental nding on routine dental radiographs, both intra-and extraoral.

Conflicts of Interest
e authors declare no con icts of interest.