A 7-year-old boy presented with a slowly growing, asymptomatic lump on his left lower neck since birth. His parents denied any medical history of trauma, infection, or surgery. Physical examination showed a 1.3 × 0.7 × 0.6 cm, yellowish, hump-like mass with hairy surface and cartilage-like consistency on the anterior border of the lower third of the left sternocleidomastoid muscle (SCM) (Figure, A). No other anomalies were observed. Ultrasonography revealed a 1.2 × 1.0 × 0.9 cm, hypoechoic, avascular, bulging nodule with an anechoic tubular structure extending to the subcutaneous fat and reaching the surface of the muscular layer. Magnetic resonance imaging (MRI) demonstrated a protuberant nodule with diffuse, slight hyperintensity on T1WI; and 2 mild hyperintense foci surrounded by hypointense tissue on fat-suppressed T2WI (Figure, B). The neck mass was completely excised under general anesthesia in the department of pediatric surgery. Intraoperatively, the mass extended into the anteromedial fascia of the left SCM and did not involve the deeper neck structures. Postoperative histopathologic analysis showed normal-appearing epidermis, multiple pilosebaceous follicles, abundant adipose tissue, and 2 centrally circumscribed segments of cartilage in the subcutis (Figure, C). Van Gieson stain highlighted elastic fibers surrounding individual chondrocytes.