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 ] .
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.]
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.
- Usefulness of dermoscopy for the diagnosis of epidermal cyst: the ‘pore’ sign Ghigliotti G, Cinotti E, Parodi A. Clin Exp Dermatol.2014;39(5):649-650.
- The diagnosis of pilomatrixoma in children is not as easy as it may seem: a review of 126 cases [in Spanish] Fernández Atuan R, Álvarez García N, González Ruiz Y, Siles Hinojosa A, Rihuete Heras MA, Elías Pollina J. Cir Pediatr.2017;30(1):46-49.