Select location (midline vs anterior triangle vs posterior triangle), mobility with swallowing/tongue protrusion, tenderness, fluctuance, transillumination, systemic symptoms, and ultrasound findings → differentiate thyroglossal duct cyst, branchial cleft cyst, cystic hygroma, reactive/suppurative adenitis, lymphoma, or dermoid.
⚠️ Red flags: supraclavicular node, rapidly growing firm mass, systemic symptoms (fever, weight loss, night sweats) → excisional biopsy, chest X‑ray for mediastinal mass.
Select midline vs lateral, movement with tongue protrusion (thyroglossal), transillumination (cystic hygroma), tenderness (adenitis), fluctuance (abscess), supraclavicular location, and systemic symptoms (fever, weight loss, night sweats) → differentiate congenital (thyroglossal, branchial, dermoid, cystic hygroma) from infectious (viral, bacterial, atypical mycobacteria) from malignant (lymphoma, metastatic).