Ultra-High-Frequency Ultrasound Reveals Insights into Pilomatricoma in Children

Acoustic shadowing is a phenomenon that occurs in ultrasound imaging, where sound waves are blocked or attenuated by a dense structure, leading to a shadowing effect behind it. This effect can provide valuable insights into the internal structures of tissues and organs, aiding in the diagnosis and evaluation of various medical conditions.

In a recent study published in Frontiers in Medicine, researchers investigated the use of ultra-high-frequency ultrasound in the evaluation of paediatric pilomatricoma based on histopathologic classification. Pilomatricoma, also known as calcifying epithelioma of Malherbe, is a benign tumour derived from hair cortex cells and is one of the most common benign tumours in children.

The study aimed to explore the ultra-high-frequency ultrasonographic features of pilomatricoma in a large paediatric cohort and determine the associations of these features with different histological subtypes of pilomatricoma. The research included patients who underwent preoperative ultra-high-frequency ultrasonographic evaluation and had a pathological diagnosis of pilomatricoma.

A total of 133 patients with pilomatricoma were included in the study, with 147 pilomatricoma lesions analyzed. The findings revealed that pilomatricoma presented as heterogeneous, well-demarcated, and hypoechoic tumours located between the deep dermis and subcutaneous tissue on ultra-high-frequency ultrasonography. The most common features observed were internal echogenic foci, hypoechoic rim, and posterior acoustic shadowing.

Histologically, the pilomatricoma lesions were classified into four stages: early, fully developed, early regressive, and late regressive stages. Three calcifying types, including scattered dots, clumps, and arcs, were observed on histological examination, which corresponded well with grey-scale imaging on ultra-high-frequency ultrasonography. Each calcifying type was significantly different in various histological stages, with scattered dots mainly present in early and fully developed stages, while arc-shaped calcifications were present in regressive stages.

The study also compared the ultrasonographic features of pilomatricoma with infantile hemangiomas and skin cysts. Infantile hemangiomas were found to be well-defined and hypoechoic on ultrasound, while skin cysts showed more frequent posterior enhancement and less frequent posterior shadowing compared to pilomatricoma.

In conclusion, the study demonstrated that ultra-high-frequency ultrasound is a useful tool for the diagnosis and evaluation of pilomatricoma in paediatric patients. The identification of specific ultrasonographic features, such as calcifying types and hypoechoic rim, can aid in the staging of pilomatricoma and improve diagnostic accuracy. Further research with larger samples and prospective studies are needed to validate these findings and enhance our understanding of pilomatricoma evaluation using ultra-high-frequency ultrasound.