Current Topics in Diagnostic Imaging of the Pediatric Neck Eiji Oguma, M.D. Department of Radiology, Saitama Children s Medical Center NICHIDOKU-IHO Vol. 49 No. 4 61 83 (2004) Summary This article focuses on several major topics in diagnostic imaging of the pediatric neck and describes them in four sections. These topics include imaging features of neck infections, congenital cystic masses of the neck, vascular lesions (infantile hemangioma and vascular malformation), and tumoral lesions of the neck. In section 1, this review discusses the clinical characteristics and imaging findings of respiratory emergencies in children, including croup, epiglottitis, and retropharyngeal abscess. Conventional films still can be used for a preliminary survey in the diagnosis of these respiratory emergencies in children, especially for differentiation between croup and epiglottitis, and for the retropharyngeal space when there is a question of a retropharyngeal abscess. In section 2, diagnostic imaging of congenital cysts and fistulas of the pediatric neck are described. Thyroglossal duct cysts are the most common malformations of the pediatric neck region, and the diagnosis is usually straightforward. Lateral cervical lesions usually are derived from developmental anomalies of the branchial clefts, and the most common lesions are cysts and fistulas of the second cleft. Pyriform sinus fistulas typically present as acute suppurative thyroiditis but frequently make large retention cysts that may obstruct the upper airways in neonates and infants. Complete surgical excision of the fistula is the treatment of choice, and diagnostic imaging provides useful information. Section 3 emphasizes differentiation between infantile hemangioma and vascular malformation according to the classification of the International Society for the Study of Vascular Anomalies (ISSVA). The vast majority of vascular lesions of infancy and childhood can be classified as hemangioma or vascular malformation. Infantile hemangiomas are benign neoplasms that proliferate rapidly in infancy only to involute in early childhood. Vascular malformations are vessel abnormalities that result from developmental anomalies of vascular morphogenesis. They derive from embryonal capillary, venous, arterial, or lymphatic channels, or combinations of these. Several relative lesions of common infantile hemangioma are described. These include rapidly involuting congenital hemangioma (RICH), non-involuting congenital hemangioma (NICH), and Kaposiform hemangioendothelioma (KHE). RICH and NICH have similar clinical and radiologic characteristics. The obvious differences in growth and involutional behavior serve to differentiate RICH, NICH, and infantile hemangioma. KHE is a rare vascular tumor, predominantly of infancy and early childhood, which frequently leads to Kasabach-Merritt syndrome. In the fourth and final section, several pediatric neck neoplastic lesions are discussed. Rhabdomyosarcoma, neuroblastoma, and Langerhans cell histiocytosis are described, with classical images shown as examples.
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