By MRCSA in MRCS Part A — 04 Jul 2026

30 NECK LUMPS

# 31 NECK LUMPS

Neck lumps are an examiner's playground. They reward candidates who can map a clinical sign to an anatomical compartment, then collapse the differential by age and behaviour of the lump. The trick is not memorising every lesion — it is having a reproducible system: where is it, who is the patient, and what does it do when they swallow or stick out their tongue?

Triangles of the neck

Sternocleidomastoid (SCM) divides the neck into an anterior and a posterior triangle. Each is further subdivided by the digastric and omohyoid bellies. Knowing which compartment a lump sits in halves the differential.

➡ Anterior triangle — bounded by the midline, mandible and anterior border of SCM. Four subdivisions:

- Submental — between the anterior bellies of digastric and the hyoid. Contains submental lymph nodes draining the tip of the tongue and lower lip.

- Submandibular (digastric) — between the two bellies of digastric and the mandible. Contains the submandibular gland, facial artery and submandibular nodes.

- Carotid — between posterior belly of digastric, superior belly of omohyoid and anterior border of SCM. Contains the carotid sheath (carotid artery, IJV, vagus) and deep cervical nodes.

- Muscular — between superior belly of omohyoid, anterior SCM and midline. Contains the strap muscles, thyroid and larynx.

➡ Posterior triangle — bounded by posterior border of SCM, anterior border of trapezius and middle third of the clavicle. Two subdivisions:

- Occipital — above the inferior belly of omohyoid. Contains the accessory nerve (most superficial structure), cervical plexus and occipital nodes.

- Supraclavicular (subclavian) — below omohyoid. Contains the third part of the subclavian artery, brachial plexus trunks and supraclavicular nodes (including Virchow's on the left).

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The clinical approach

When faced with a neck lump in an exam stem, ask four questions in this order:

1. Midline or lateral? Midline lumps are short list (thyroid, thyroglossal, dermoid, submental node). Lateral lumps open up the full differential.

2. What does it do on swallowing and tongue protrusion? Thyroid lumps rise on swallowing only. Thyroglossal cysts rise on both swallowing AND tongue protrusion (they tether to the hyoid via the thyroglossal tract). Lymph nodes and dermoids do neither.

3. How old is the patient? Cystic hygroma in a neonate. Branchial cyst in a young adult. Reactive nodes in children and teenagers. Metastatic SCC in an older smoker.

4. Painful or painless? Painful suggests infection or rapidly expanding bleed into a cyst. Painless, slow growing in an older patient is malignancy until proven otherwise.

👩‍⚕️ The "Iso of Doom" rule — a solitary, hard thyroid nodule in an older patient (especially male, with hoarseness or rapid growth) is thyroid malignancy until proven otherwise. Solitary cold nodules carry a much higher malignancy risk than nodules in a multinodular goitre.

Midline lumps

Thyroid swellings

Move on swallowing only, because the thyroid is tethered to the pretracheal fascia and therefore to the larynx. Differential includes multinodular goitre, solitary nodule (cyst, adenoma, carcinoma) and thyroiditis. Investigate with USS + FNA; thyroid function tests rarely change the surgical plan but exclude Graves'.

Thyroglossal cyst

The commonest congenital midline neck lump. It is a remnant of the thyroglossal duct — the embryological track along which the thyroid descends from the foramen caecum (junction of anterior two-thirds and posterior third of the tongue) down through (and often around) the hyoid to its final pretracheal position.

Because the cyst is tethered to this tract, it elevates when the tongue is protruded — the single most useful physical sign in the lesson. Classically presents in childhood or young adulthood as a midline, smooth, fluctuant lump just below the hyoid. May contain ectopic thyroid tissue (occasionally the patient's only functioning thyroid — request USS before excising).

Treatment is the Sistrunk procedure: excision of the cyst, the central portion of the hyoid bone, and the tract up to the foramen caecum. Simple excision leaves the tract and recurs.

Dermoid cyst

Sits in the midline, often submental or sublingual. Arises from epithelial rests trapped along fusion lines during embryogenesis. Moves with the skin (it is attached to skin), does not move on swallowing or tongue protrusion. Contains keratin and sometimes hair or sebaceous material.

Lateral lumps — upper neck

Cervical lymph nodes

Far and away the commonest neck lump at every age. Examined in levels I–V (plus VI central compartment, VII superior mediastinal). For MRCS purposes, three patterns matter:

- Reactive lymphadenopathy — tender, mobile, soft. Common in children with URTI. Self-limiting.

- Tuberculous lymphadenitis ("scrofula") — matted, non-tender, may cold-abscess and form a discharging sinus. Classically posterior triangle. Think of it in patients from endemic areas or with HIV.

- Lymphoma — painless, rubbery, multiple sites, may have B symptoms (fever, night sweats, weight loss). Diagnosed by excision biopsy, NOT FNA — architecture matters for subtyping.

- Metastatic SCC — hard, fixed, in an older smoker. Hunt for a primary in the oral cavity, oropharynx, larynx or skin. Left supraclavicular node (Virchow's) drains the abdomen — think gastric.

Branchial cyst

Classically presents in a young adult (15–30) as a painless, fluctuant swelling at the junction of the upper third and lower two-thirds of the anterior border of SCM (i.e. anterior to SCM, deep to its upper portion). Embryologically a remnant of the second pharyngeal arch / cervical sinus, which fails to obliterate.

FNA classically shows cholesterol crystals — a near-pathognomonic finding and a favourite SBA pearl. Treatment is surgical excision; beware accessory nerve in the posterior triangle and the branches of the facial nerve superiorly.

Parotid tumours

Present as a lump in front of and below the ear, lifting the earlobe. The 80% rule is the high-yield mnemonic:

- 80% of salivary tumours arise in the parotid.

- 80% of parotid tumours are benign.

- 80% of benign parotid tumours are pleomorphic adenoma.

Tumour	Behaviour	Key features
Pleomorphic adenoma	Benign, slow-growing	Commonest. Risk of malignant transformation if left. Excise with cuff of normal tissue.
Warthin's tumour	Benign	Older men, smokers, often bilateral. "Papillary cystadenoma lymphomatosum."
Mucoepidermoid carcinoma	Malignant (commonest)	Variable grade. Painless mass that may invade facial nerve.
Adenoid cystic carcinoma	Malignant	Perineural spread; pain and facial nerve palsy are red flags.

Submandibular gland tumours follow a roughly 50/50 benign:malignant split — a smaller gland is more likely to harbour a malignancy. Sublingual and minor salivary gland tumours are usually malignant.

👩‍⚕️ Facial nerve palsy in a parotid lump = malignancy until proven otherwise. Benign tumours displace the nerve; malignant tumours invade it.

Carotid body tumour (chemodectoma / paraganglioma)

Arises from chemoreceptor cells at the carotid bifurcation. Presents as a pulsatile, mobile-side-to-side-but-not-up-and-down mass at the angle of the jaw. On imaging there is classical splaying of the internal and external carotid arteries at the bifurcation ("lyre sign" on angiography). Bruit may be audible. Do not biopsy — refer for vascular imaging and surgical excision.

Lateral lumps — lower neck

Cervical rib

A bony or fibrous extension from the C7 transverse process. May be asymptomatic or cause thoracic outlet syndrome — neurogenic symptoms (T1 ulnar territory) more commonly than vascular. Palpable as a hard, fixed swelling in the supraclavicular fossa.

Cystic hygroma

A congenital macrocystic lymphatic malformation, almost always presenting at birth or in the first two years. Classic location is the posterior triangle, soft, fluctuant, and brilliantly transilluminant — this last sign distinguishes it from every other neck lump. Strongly associated with Turner syndrome (45,X0) and may be detected antenatally.

Subclavian artery aneurysm

Rare but classically tested. Presents as a pulsatile supraclavicular mass, often associated with cervical rib (chronic compression causes post-stenotic dilatation). Look for distal embolic phenomena in the hand.

Investigations

Investigation	Role
Ultrasound	First-line for almost every neck lump. Distinguishes solid from cystic, characterises thyroid nodules (U1–U5), guides FNA.
FNA / FNAC	Cytological diagnosis of solid lesions. Pathognomonic for branchial cyst (cholesterol). NOT used for suspected lymphoma.
Excision biopsy	Mandatory for suspected lymphoma — needs architecture for subtyping.
CT neck (+ chest)	Staging of malignancy, anatomical mapping before surgery.
MRI	Soft-tissue characterisation, particularly parotid tumours and assessment of facial nerve involvement.

[Image: MCQs banner]

Test yourself

A patient presents with a painless lump in the anterior triangle of the neck that moves upwards on swallowing and protrusion of the tongue. What is the most likely diagnosis?

((Thyroglossal cyst::☑️ Midline lump tethered to the hyoid; moves on both swallowing AND tongue protrusion.))
((Branchial cyst::Anterior to SCM at upper/middle third junction; does not move with tongue protrusion.))
((Dermoid cyst::Attached to skin; moves with skin, not deep structures.))
((Thyroid nodule::Moves with swallowing only — tethered to pretracheal fascia, not tongue.))
((Lymph node::Neither swallowing nor tongue protrusion shifts a node.))

👩‍⚕️ Movement on tongue protrusion is the single most discriminating sign in midline neck lumps.

Which of the following features is NOT characteristic of a thyroglossal cyst?

((Midline neck lump::Characteristic — thyroglossal cysts are virtually always midline.))
((Moves with swallowing::Characteristic — tract attaches to the hyoid.))
((Moves with tongue protrusion::Characteristic — duct connects to foramen caecum.))
((Anterior to sternocleidomastoid::☑️ Thyroglossal cysts are midline; SCM relations describe branchial cysts.))
((Contains thyroid tissue::Characteristic — may contain ectopic (sometimes only) thyroid tissue.))

A thyroglossal cyst must be excised. Which operation is performed?

((Sistrunk procedure::☑️ Excises cyst, central hyoid AND tract to foramen caecum — prevents recurrence.))
((Block dissection::Used for nodal clearance in head and neck malignancy.))
((Simple excision::Leaves the tract behind — high recurrence rate.))
((Total thyroidectomy::Wrong organ — the cyst is a duct remnant, not thyroid pathology.))
((Subtotal excision::Incomplete removal of the tract recurs.))

👩‍⚕️ Always image the neck before Sistrunk — the cyst may contain the patient's only functioning thyroid tissue.

A 20-year-old presents with a painless fluctuant mass in the anterior triangle of the neck, posterior to the sternocleidomastoid at the junction of the upper ⅓ and lower ⅔. What is the most likely diagnosis?

((Thyroglossal cyst::Midline structure — wrong location.))
((Branchial cyst::☑️ Classic — young adult, anterior to SCM at upper third / lower two-thirds junction.))
((Cystic hygroma::Posterior triangle, neonates, transilluminant.))
((Lymphoma::Firm, rubbery, often multiple — rarely fluctuant.))
((Reactive lymphadenopathy::Tender, mobile and usually follows a URTI.))

A patient has a lump deep to SCM at the junction of the upper and middle third. FNAC shows cholesterol crystals. What is the diagnosis?

((Branchial cyst::☑️ Cholesterol crystals on FNAC are pathognomonic.))
((Thyroglossal cyst::Cytology shows squamous/thyroid epithelium, not cholesterol.))
((Cystic hygroma::Contains chylous lymph, not cholesterol crystals.))
((Sebaceous cyst::Contains keratin and is attached to skin.))
((Lymph node::FNAC shows lymphoid tissue — reactive, lymphomatous or metastatic.))

👩‍⚕️ Cholesterol crystals on FNAC = branchial cyst. Classic one-line SBA.

Which embryological structure gives rise to a branchial cyst?

((First pharyngeal arch::Gives rise to muscles of mastication, mandible, malleus and incus.))
((Second pharyngeal arch::☑️ Failure of obliteration of the cervical sinus of His.))
((Third pharyngeal arch::Stylopharyngeus, common and internal carotid, inferior parathyroids.))
((Fourth pharyngeal arch::Cricothyroid, superior parathyroids, laryngeal cartilages.))
((Thyroglossal duct::Gives rise to thyroglossal cysts, not branchial cysts.))

A newborn presents with a large, soft, transilluminant swelling in the posterior triangle of the neck. What is the most likely diagnosis?

((Cystic hygroma::☑️ Congenital lymphatic malformation — posterior triangle, brilliantly transilluminant.))
((Branchial cyst::Anterior triangle in young adults, not neonates.))
((Thyroglossal cyst::Midline structure.))
((Haemangioma::Vascular, blanches with pressure, does not transilluminate brilliantly.))
((Dermoid cyst::Attached to skin, midline, does not transilluminate.))

Cystic hygroma is associated with which chromosomal abnormality?

((Turner syndrome::☑️ 45,X0 — cystic hygroma is a classic antenatal/neonatal finding.))
((Down syndrome::Trisomy 21 — duodenal atresia, AVSD, Hirschsprung's.))
((Edwards syndrome::Trisomy 18 — rocker-bottom feet, overlapping fingers.))
((Patau syndrome::Trisomy 13 — holoprosencephaly, cleft lip and palate.))
((Klinefelter syndrome::47,XXY — tall stature, gynaecomastia, infertility.))

👩‍⚕️ Antenatal cystic hygroma → karyotype to exclude Turner syndrome.

A 60-year-old smoker presents with a slow-growing painless lump in front of the ear, lifting the earlobe. Facial movements are normal. What is the most likely diagnosis?

((Pleomorphic adenoma::☑️ Commonest parotid tumour; benign, slow, painless, no facial nerve involvement.))
((Mucoepidermoid carcinoma::Commonest parotid malignancy — would more often involve the facial nerve.))
((Warthin's tumour::Benign, older male smokers, often bilateral — possible but less common than pleomorphic.))
((Adenoid cystic carcinoma::Malignant; perineural spread causes pain and facial palsy.))
((Parotid lymphoma::Rare; usually presents with diffuse swelling rather than a discrete lump.))

👩‍⚕️ 80% salivary tumours are parotid; 80% parotid tumours are benign; 80% of those are pleomorphic adenoma.

A 45-year-old presents with a pulsatile lump at the angle of the jaw. Imaging shows splaying of the internal and external carotid arteries. What is the diagnosis?

((Carotid body tumour::☑️ Paraganglioma at the bifurcation — classic "lyre sign" splaying ICA and ECA.))
((Branchial cyst::Fluctuant, not pulsatile; FNA shows cholesterol crystals.))
((Carotid aneurysm::Pulsatile but does not splay the bifurcation.))
((Metastatic lymph node::Hard and fixed, not pulsatile; no vascular splaying.))
((Glomus jugulare::Skull base lesion presenting with pulsatile tinnitus and lower cranial nerve palsies.))

A 70-year-old smoker presents with a hard, fixed lump in the left supraclavicular fossa. What is the most appropriate first investigation to find the primary?

((USS-guided FNA of the node::Cytology helps confirm metastatic SCC but does not localise the primary.))
((CT neck, chest, abdomen and pelvis::☑️ Left supraclavicular (Virchow's) node drains the abdomen — gastric primary must be excluded.))
((Excision biopsy::Reserved for suspected lymphoma; risks seeding if SCC.))
((Panendoscopy alone::Useful for head and neck primary but misses an abdominal source.))
((PET-CT::Useful adjunct but not first line in most UK pathways.))

👩‍⚕️ Left supraclavicular node = Virchow's = think abdominal (gastric) primary.

A young adult presents with painless, rubbery, mobile lymphadenopathy in multiple cervical levels and night sweats. What is the most appropriate diagnostic investigation?

((FNA cytology::Insufficient — lymphoma diagnosis and subtyping require nodal architecture.))
((Excision lymph node biopsy::☑️ Provides whole-node architecture needed to subtype lymphoma.))
((Core biopsy::Acceptable second-line but excision remains gold standard.))
((USS neck::Useful for mapping but does not give a tissue diagnosis.))
((Bone marrow biopsy::Part of staging once lymphoma is confirmed, not the initial diagnostic test.))

Revision summary

➡ Anterior triangle = midline → SCM; posterior triangle = SCM → trapezius → clavicle.

➡ Movement: thyroid = swallowing only; thyroglossal = swallowing + tongue protrusion; nodes and dermoid = neither.

➡ Thyroglossal cyst — midline, from foramen caecum, treated by Sistrunk (cyst + central hyoid + tract).

➡ Branchial cyst — 2nd pharyngeal arch remnant; anterior to SCM at upper ⅓ / lower ⅔ junction; FNA = cholesterol crystals.

➡ Cystic hygroma — neonate, posterior triangle, brilliantly transilluminant, associated with Turner syndrome (45,X0).

➡ Parotid 80/80/80 rule — 80% salivary in parotid, 80% benign, 80% pleomorphic adenoma. Facial nerve palsy = malignancy.

➡ Carotid body tumour — pulsatile, splays bifurcation (lyre sign), do not biopsy.

➡ Lymphadenopathy — TB matted/cold abscess; lymphoma rubbery/painless → excision biopsy; metastatic SCC hard/fixed in older smoker; Virchow's (left supraclavicular) = abdominal primary.

➡ Cervical rib → thoracic outlet syndrome and subclavian aneurysm in the supraclavicular fossa.

➡ First-line investigation for almost every neck lump = USS ± FNA. Suspected lymphoma = excision biopsy. Malignancy staging = CT.