Expansion
Position, movement and age narrow the differential rapidly
Expansion
Midline
- Thyroid: moves on swallowing
- Thyroglossal cyst: moves on swallowing and on tongue protrusion; commonest midline neck swelling in a child
- Dermoid cyst
Anterior triangle
- Lymph nodes (much the commonest)
- Branchial cyst: young adult, anterior border of sternocleidomastoid, upper third
- Carotid body tumour: pulsatile, mobile side to side but not up and down
- Salivary gland: submandibular or parotid
Posterior triangle
- Lymph nodes, cystic hygroma in infants
Approach: age is the strongest discriminator. In children most lumps are inflammatory or congenital; in adults over 40 a persistent lump is malignant until proven otherwise.
Investigation is by ultrasound with fine needle aspiration. In a suspected metastatic node, excision biopsy should be avoided, since it compromises subsequent neck dissection and seeds the field; the correct pathway is panendoscopy with biopsy of the likely primary in the head and neck.