Most children in the ED with a neck mass are not in distress; the leading diagnoses are reactive adenopathy or acute lymphadenitis from viral or bacterial infection A common concern, however, is deciding which neck mass bears the diagnosis of malignancy and requires biopsy or further evaluation Table 48.2 lists common nonemergent causes of neck mass History To facilitate differential diagnosis development, it is crucial to determine both the patient’s age when the mass was first noticed, as well as current symptom duration A neck mass presenting at several weeks of life may represent birth trauma with hemorrhage into the sternocleidomastoid and resulting torticollis Conversely, congenital cysts may not come to attention until they have enlarged with infection or inflammation, often increasing in size with recurrence Details of chronicity, size, progression, and evidence of inflammation (e.g., dimples, sinuses, drainage over time), can help to distinguish between infection and neoplasm Although longer duration is concerning for malignancy, the duration the “node” is present is not reliable in discriminating benign from malignant TABLE 48.2 COMMON CAUSES OF NECK MASS Lymphadenopathy secondary to viral or bacterial infection Cervical adenitis (bacterial) Hematoma Benign tumors—lipoma, keloid Congenital cyst (squamous epithelial cysts)