Congenital Squamous epithelial cyst (congenital or posttraumatic) Pilomatrixoma (Malherbe calcifying epithelioma) Hemangioma and cystic hygroma (lymphangioma) Branchial cleft cyst Thyroglossal duct cyst Laryngocele Dermoid cyst Cervical rib Inflammatory Infection Cervical adenitis—streptococcal, staphylococcal, fungal, mycobacterial, cat-scratch disease, tularemia Adenopathy—secondary to local head and neck infection Secondary to systemic “infection”—infectious mononucleosis, Cytomegalovirus, toxoplasmosis, others Retropharyngeal abscess Focal myositis—inflammatory muscular pseudotumor Lemierre syndrome “Antigen” mediated Local hypersensitivity reaction (sting/bite) Serum sickness, autoimmune disease Pseudolymphoma (secondary to phenytoin) Mucocutaneous lymph node syndrome (Kawasaki disease) Sarcoidosis Caffey–Silverman syndrome Trauma Hematoma Sternocleidomastoid tumor of infancy (fibromatosis colli) Subcutaneous emphysema Acute bleeding Arteriovenous fistula Foreign body Cervical spine fracture Neoplasms Benign