Epidemiologic Comparison of Epidermal Cysts and Pilomatrixomas in Pediatric Patients: A 13-Year Single-Institution Study

Background/Objectives: Epidermal cysts and pilomatrixomas are 2 of the most common benign skin lesions in children, yet comprehensive epidemiologic data comparing their distribution remain limited. This study aimed to evaluate the prevalence of these lesions in pediatric patients over a 13-year period at a single institution. Methods: A retrospective review was conducted of patients aged 0 to 18 years who underwent excisional biopsy with histopathologic confirmation between 2012 and 2025. Cases diagnosed as epidermal cysts or pilomatrixomas were included for comparative analysis. Age was categorized into 4 groups (0–4, 5–9, 10–14, and 15–18 y), and lesion locations were grouped into head and neck, upper extremities, lower extremities, and trunk. Results: Among 731 pediatric patients, 118 (16%) had epidermal cysts, and 161 (22%) had pilomatrixomas. Epidermal cysts demonstrated a relatively even age distribution, whereas pilomatrixomas were concentrated in the first decade of life, particularly in the 5- to 9-year age group. Both lesions showed a female predominance. The head and neck region was the most common site for both lesions; however, pilomatrixomas exhibited a higher proportion of upper-extremity involvement and were rarely observed on the trunk. Conclusions: This long-term single-institution study provides internally consistent epidemiologic data on 2 common pediatric skin lesions. Age-, sex-, and site-specific distribution patterns identified in this cohort may assist clinicians in improving preoperative diagnostic suspicion and counseling.