Considering the anatomy and associated pathology, the lump may represent: • Artery: carotid artery aneurysm, subclavian artery aneurysm, carotid body tumour (i.e. chemodectoma or paraganglioma of the carotid body) • Nerves: neurofibroma, schwannoma • Lymphatics: lymphatic malformations • Lymph nodes: infective, neoplastic (primary or metastatic), granulomatous • Salivary glands: infective, autoimmune, neoplastic • Larynx: laryngocele • Pharynx: pharyngeal pouch • Branchial arch remnant: branchial cyst/sinus/fistula • Skin/superficial subcutaneous: lipoma, epidermal cyst, abscess, dermoid cyst • Muscle/cartilage/bone: sarcomas (e.g. rhabdomyosarcoma, fibrosarcoma, osteosarcoma), cervical rib, torticollis The age of the patient has an enormous bearing upon the pathology you should expect to encounter: • In children, about 75% of neck lumps are benign. Congenital and inflammatory lumps are most common. Thus the differential diagnosis will be weighted in favour of branchial cleft cysts, lymphatic malformations, and lymphadenitis. If malignancy is diagnosed in paediatric neck lumps, it is usually a lymphoma or sarcoma, or sometimes a papillary thyroid carcinoma. • In adults over 40, as many as 75% of lateral neck lumps are malignant. Of the malignant neck lumps, about 80% are metastases and the rest are mostly lymphomas. In fact, ▲ in the absence of signs of infection, a lateral neck mass in an adult is lymphadenopathy due to metastatic carcinoma (usually squamous cell) until proven otherwise. • How long has the lump been there? ■ Less than a few weeks: most likely infective or inflammatory lymphadenopathy, although some patients will present with malignant neck lumps that have only been noticed within the last few days. ■ More than a few weeks: must exclude malignancy. ■ Years, with little change: most likely benign. ■ Note that congenital neck lumps, despite being ‘congenital’, may only ‘appear’ later in life as they may fluctuate in size (e.g. following an infection). • Has the lump got bigger, smaller, or stayed the same size? A lump that is gradually increasing in size must be regarded as a malignancy until proven otherwise. Remember that a progressive increase in size of a malignant neck lump may be reported as a sudden appearance by the patient.