Ultrasonography of pediatric cutaneous and subcutaneous masses

Cutaneous and subcutaneous lumps are frequently encountered in the pediatric population and are usually benign. Although some lesions can be diagnosed clinically, ultrasound plays a pivotal role in evaluation by delineating lesion morphology, depth, extent, internal composition, and vascularity. Technological advances in high-frequency transducers and image resolution have significantly improved visualization of superficial soft tissues, enhancing diagnostic confidence. Despite substantial overlap in sonographic appearance among different lesions, specific imaging characteristics can help narrow the differential diagnosis and guide management. This review summarizes both common and uncommon pediatric superficial soft tissue masses, emphasizing their tissue of origin, key ultrasound features, and distinguishing findings that assist in accurate characterization and appropriate clinical decision-making. Conditions covered include epidermal inclusion cysts, sebaceous cysts, hair follicle lesions (hidradenitis suppurativa, pilonidal sinus disease, pilomatricomas, trichilemmal cysts), juvenile xanthogranulomas, dermatofibromas, subcutaneous granuloma annulare, and cutaneous leukemia/lymphoma.