Epidermal Cyst on the Face of a Child, Clinically and Dermoscopically Mimicking Pilomatricoma.

Introduction

We present a case of an epidermal cyst on the face of a child, clinically and dermoscopically mimicking pilomatricoma. Pilomatricoma, also called pilomatrixoma or calcifying epithelioma of Malherbe, is a benign skin tumor and one of the most common causes of superficial head and neck masses in children and young adults [1]. It usually manifests as a solitary, asymptomatic, firm nodule on the face (especially eyelids and eyebrows), scalp, neck, or arms [1]. Common differential diagnoses for head and neck pilomatricoma include sebaceous cyst, ossifying hematoma, giant cell tumor, chondroma, dermoid cyst, foreign body reaction, degenerating fibroxanthoma, metastatic bone formation, and osteoma cutis [1]. Pilomatricoma-like changes have been described in epidermoid cysts in patients with Gardner syndrome [1]. Surgical excision of the pilomatricoma is the treatment of choice, with wide resection margins to minimize the risk of recurrences [2].

Case Presentation

In our case, a 6-year-old girl presented clinically with a preauricular, firm, solitary lesion that had been growing slowly for the 2 months before the first visit (Figure 1). Dermoscopy revealed erythematous border, irregular white structures, and brown-blue central pigmentation (Figure 2).

Figure 1

Clinical presentation of a preauricular, firm, solitary lesion on the face of a 6-year-old girl. [Copyright: ©2019 Krtanjek et al.]

Figure 2

Dermoscopy image of the lesion (Dermlite 3Gen PRO HR II, Nikon Coolpix). Erythematous surrounding skin, irregular white structures, and brown-blue central pigmentation. [Copyright: ©2019 Krtanjek et al.]

Based on the clinical and dermoscopic examination, the initial diagnosis was pilomatricoma with differential diagnosis of foreign body reaction. After 1 month, the lesion enlarged quickly; therefore, excision was advised. Histopathology report demonstrated a cyst lined by an epidermis-like epithelium including a granular cell layer, filled with laminated keratin, compatible with a diagnosis of epidermal cyst (Figure 3).

Figure 3

A cyst lined by an epidermis-like epithelium including a granular cell layer, filled with laminated keratin. [Copyright: ©2019 Krtanjek et al.]

Conclusions

We believe that this is the first report of an epidermal cyst on the face of a child with these dermoscopic features. Given its frequent incidence, this diagnosis should be considered when evaluating similar skin lesions, to avoid unnecessary surgical excision.