A 41-year-old patient with a 4-year history of an asymptomatic, slowly growing erythematous nodule on her left earlobe specifically in the piercing site.

The clinical exam found a patient in good general condition with, on skin examination, an erythematous nodule, well limited, smooth, located in the piercing site, measuring 10×10 mm in size (Fig. 1a). The right earlobe was normal.

Figure 1: (a) Cutaneous sarcoidosis on left earlobe: Clinical presentation. (b) Dermoscopic examination reveals diffuse orangish color as well as well-focused linear-irregular vessels and whitish linear areas, scar-like whitish areas are also visible. (c) Typical histopathological features of sarcoidosis: Epithelioid granuloma without caseous necrosis.

What is your diagnosis?

Dermoscopy of the nodule was performed using Dermlite DL4 revealing branching and multiple vessels and yellowish-orange structureless areas (Fig. 1b). Faced with this dermoscopic aspect, the diagnosis of a granulomatous pathology was evoked in particular cutaneous sarcoidosis or a foreign body granuloma.

A skin biopsy of the nodule was performed revealing multiple well-formed granulomas in the dermis, composed of epithelioid cells, histiocytes, a few multinucleated giant cells, and lymphocytes, with no evidence of caseous necrosis (Fig. 1c).

Thus, the diagnosis of cutaneous sarcoidosis was confirmed.

The systematization assessment was normal.

The patient was treated with intralesional injection of steroids and topical steroids with good outcomes.

Herein we report a case of cutaneous sarcoidosis on the site of piercing of the earlobe mimicking a keloid. In fact, sarcoidosis is a chronic, multisystem inflammatory disease of unknown etiology [1–3].

Cutaneous sarcoidosis can present as specific or nonspecific lesions, depending on the presence or absence of sarcoidal granulomas. Specific lesions include macules, papules, plaques, subcutaneous nodules, ulcerations, and more. Nonspecific lesions are reactive conditions such as erythema nodosum, calcification, erythema multiforme, prurigo. Due to its diverse clinical presentations, sarcoidosis is often referred to as a “great imitator”[4].

Sarcoidosis can sometimes occur on the scars, its prevalence in this context is estimated at around 5%. Scar Sarcoidosis is characterized by the infiltration of surgical scars, tattoos, skin piercing, and other sites of trauma [5].

Scar sarcoidosis mainly affects women in 60% of cases, with an average onset around the age of 45. The time between the modification of the scar and the trauma is on average 20 years [6].

The exact mechanism remains unclear, but foreign body inoculation during minor trauma has been proposed as a trigger for granuloma formation in predisposed individuals [7].

Dermoscopy is a non-invasive tool to aid the diagnosis of cutaneous sarcoidosis and differentiate it from hypetrophic and keloid scars [8].

The most significant dermatoscopic feature of cutaneous sarcoidosis is the presence of translucent, orange, ovoid structures. Additionally, bright white streaks, central scar-like areas and linear blood vessels, are commonly observed. Hair follicle plugs are relatively infrequent [9].

The dermoscopic features of keloids and hypertrophic scars have been rarely reported. It is distinguished by the lack of yellow-orange structures. Dermoscopy typically shows that keloids display vascular patterns in most cases (90%), with arborizing vessels being the most frequent, followed by irregular linear and comma-shaped vessels. In contrast, hypertrophic scars are characterized by the presence of scarring and fibrosis, presenting as erythematous or white patches with absent or limited vascularization in a few cases (27%) [10–12].

Histology demonstrates the classic tuberculoid granulomas of sarcoidosis [13].

The treatment of localized forms of cutaneous sarcoidosis is generally based on the use of topical corticosteroids. Topical corticosteroids are widely used due to their ease of use and relative safety, although there are no significant studies available to date. Intralesional injections of triamcinolone, 5-10 mg/ml once monthly, are reported to be effective. Topical tacrolimus can also be used as an alternative to local corticosteroid therapy [14].

The management and outlook of cutaneous sarcoidosis hinge primarily on the extent of systemic implication. Scar-related sarcoidosis typically indicates chronic disease affecting various organs but can also manifest acutely or signal a recurrence of sarcoidosis in remission, or even serve as an initial symptom of systemic sarcoidosis [15,16].

In our patient, clinical aspect was consistant with the diagnosis of keloid scar. However, dermoscopy revealed yellow-orange areas with linear vessels, compatible with granulomatous cutaneous disorder. The dermoscopy findings changed the diagnosis and led to the correct management.

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