Ultrasound of Neck Masses in Pediatrics

Abstract

US plays an important role in the evaluation of palpable neck masses in pediatric patients. The superficially located structures are easily examined and exquisitely displayed by US using a high-frequency linear array transducer. In most of the cases, US can differentiate cystic from solid lesions. For the cystic lesions, the imaging diagnosis is based on location. The midline or paramedian location of cystic neck masses in pediatrics mostly are thyroglossal duct cyst and dermoid/epidermoid when locating between hyoid bone and thyroid gland, ranula or plunging ranula when locating in sublingual or submandibular spaces, and dermoid/epidermoid again when locating at suprasternal notch. Epiglottic cyst can also be detected in its typical location when there is no intervening air. The laterally-located cystic lesions are branchial cleft cyst, venolymphatic malformation, and phlebectasia of the jugular vein. Lymphatic malformation has its typical location in posterior triangle of the neck. Contents within cystic neck masses in many cases are not echo-free and may appear as pseudo-solid lesions on US. For the solid neck masses in pediatrics, US usually can tell whether it is an enlarged lymph node or not. Like in adult, US may depict the suspicious lymph node for biopsy. The imaging diagnosis of the solid neck masses other than enlarged lymph nodes in many cases are nonspecific and need histological diagnosis. However, there are some typical solid lesions that the diagnosis could be provided, e.g., fibromatosis colli, infantile hemangioma, ectopic thymus, and ectopic thyroid.