Clinical analysis and review of literature on pilomatrixoma in pediatric patients

Abstract

Background: Pilomatrixoma is a benign tumor that originates from the hair follicle matrix. It usually presents as a hard, slow growing, solitary mass that can be easily misdiagnosed as other skin masses. The aim of this study was to clinically analyze a case series of pilomatrixoma in pediatric patients from Korea.

Methods: A total of 165 pediatric patients from 2011 to 2018 with a histological diagnosis of pilomatrixoma were included. A retrospective review was performed using the electronic medical records, including patient demographics, number and location of the mass, clinical and imaging presentation, and postoperative outcomes.

Results: There were 61 male and 104 female patients with 152 solitary and 13 multiple pilomatrixomas. Among solitary pilomatrixomas, the lesion commonly occurred in the head and neck (84.2%), followed by upper limbs (11.2%), lower limbs (3.3%), and trunk (1.3%). The pilomatrixoma lesion presented as the following types based on our clinical classification: mass (56.02%), pigmentation (25.31%), mixed (12.65%), ulceration (4.82%), and keloid-like (1.2%). Ultrasonography showed a high positive predictive value (95.56%). There were no specific complications observed except for two cases of recurrence.

Conclusion: Pilomatrixoma has various clinical feature presentations and commonly occurs in the head and neck. Ultrasonography is a helpful diagnostic tool. Surgical removal of the lesion is the main treatment method with a low recurrence rate.

Keywords: Benign neoplasms; Pediatrics; Pilomatrixoma.

Fig. 1.

Patient’s age at operation.

Fig. 2.

Affected regions in solitary pilomatrixoma. (A) Distribution of pilomatrixoma on the whole body. (B) Distribution of pilomatrixoma on the head.

Fig. 3.

Locations of multiple pilomatrixoma.

Fig. 4.

Clinical documentation of the different types of pilomatrixoma. (A) Mass type. (B) Typical mass type with the “tent sign.” (C) Pigmentation type with clearly demarcated vessels. (D) Pigmentation type with melanin-like pigmentation. (E) Mixed type. (F) Ulceration type. (G) Keloid-like type.

Fig. 5.

The ultrasound image shows a well-defined heterogeneous hyperechoic nodule with low echoic rim and internal calcifications in the subcutaneous layer of the right calf. Note the increased echogenicity in the surrounding subcutaneous fat layer and conspicuous acoustic shadowing.