Neck masses commonly present in infants and young children.These masses are typically congenital/developmental, infectious or neoplastic in origin. While neoplasm remains a primary concern, they are fortunately quite rare in children in comparison to benign soft tissue etiologies such as hemangiomas, lymphatic malformations, developmental cysts, pseudotumor (fibromatosis colli) or lymph nodes (including infectious phlegmon/abscess). Sonographic screening remains a critical initial tool in the evaluation of the pediatric neck mass.
Educational Goals / Teaching Points
Identify neck masses in children, describing the imaging findings of congenital/developmental lesions (hemangiomas, lymphatic malformations, branchial remnant/thyroglossal duct cysts) as well as common lymph nodes including post-infectious sequelae of phlegmon/abscess.
Recognize common pseudotumor of the infant neck (fibromatosis colli) resulting in neonatal torticollis.
Identify imaging findings of malignant neoplasms typically round/blue cell tumors such as lymphoma, neuroblastoma and rhabdomyosarcoma.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Standard screening neck sonographic imaging technique utilizes high megahertz linear transducer. Primary imaging goal is locating the neck mass and distinguishing cystic versus solid lesion. Clarification of distinct smooth margin of solid lesions with internal homogeneous echotexture are common features that suggest benign etiology. Color Doppler flow is a crucial component in the sonographic evaluation of a pediatric neck mass. Increased color Doppler flow seen within a solid mass raises concern for neoplastic etiology. However, if the increased color Doppler flow is significant, infectious and hemangiomatous etiologies are more likely considerations.
Focal enlargement of the sternocleidomastoid muscle (pseudotumor) suggests fibromatosis colli, a common infantile condition that manifests as neonatal torticollis. Lymph nodes have a characteristic hypoechoic, ovoid, uniform sonographic presentation with central linear echogenicity. Disrupted/heterogeneous architecture of lymph nodes with increased color Doppler flow suggests a developing infectious phlegmon.
Lack of response to antibiotic therapy and continued enlargement of a neck mass renders malignant etiology a concern with subsequent consideration for surgical excision/pathologic examination. Although rare, malignancy in the pediatric neck tends to be small, round blue cell tumors (lymphoma, neuroblastoma and rhabdomyosarcoma).
Neck masses in children are overwhelmingly benign with three basic categories to consider: congenital/developmental, infectious versus rare neoplastic origin. Sonography is an ideal primary screening imaging modality to differentiate solid vs cystic neck lesion, also using color Doppler to aid diagnosing common benign entities such as hemangiomas, lymphatic malformations, developmental cysts, pseudotumor (fibromatosis colli) or lymph nodes (including infectious deterioration into phlegmonous/abscess formation). Although rare, neck neoplasms in children tend to be small, round, blue cell tumors (lymphoma, neuroblastoma and rhabdomyosarcoma).