Surgery chapters
Disorders of the salivary glands
Anatomy of the parotid, submandibular and sublingual glands, salivary stones, sialadenitis and mumps, ranula, Sjogren's syndrome, salivary tumours (pleomorphic adenoma, Warthin, mucoepidermoid, adenoid cystic) and parotidectomy with its complications.
- The smaller the gland, the more likely a tumour is malignant: most parotid tumours are benign (commonest pleomorphic adenoma), while sublingual and minor gland tumours are mostly malignant.
- Stones form mostly in the submandibular gland (about 80%) because its saliva is thick and the duct runs uphill; most are radio-opaque; present with pain and swelling at mealtimes.
- A parotid lump is treated by superficial parotidectomy (not enucleation, which leaves pseudopodia and causes recurrence); watch for facial nerve injury, great auricular numbness and Frey's syndrome.
On this page
Overview
There are three pairs of major salivary glands (parotid, submandibular, sublingual) and hundreds of minor glands in the mouth and throat. Surgical problems are obstruction (stones), infection, cysts, autoimmune disease and tumours.
PGET usually has one MCQ here, most often on parotid tumours, submandibular stones or complications of parotidectomy.
Surgical anatomy
Parotid gland
- The largest gland; lies in front of the ear over the ramus of the mandible and masseter, from the zygoma down to the tail in the neck. Enclosed in a tough fascia (so swelling is painful, as in mumps).
- Structures passing through it (superficial to deep): facial nerve and its branches, retromandibular vein, external carotid artery (dividing into maxillary and superficial temporal arteries), plus intraparotid lymph nodes.
- The facial nerve splits the gland into a superficial lobe (about 80%) and a deep lobe (about 20%). Deep-lobe tumours may bulge into the parapharyngeal space and push the tonsil and soft palate medially.
- Duct (Stensen's): crosses the masseter, pierces the buccinator and opens opposite the upper second molar.
- Secretion is serous; parasympathetic supply comes from the glossopharyngeal nerve via the otic ganglion and auriculotemporal nerve.
Submandibular gland
- Lies in the submandibular triangle, wrapped around the posterior edge of the mylohyoid.
- Duct (Wharton's): runs forward in the floor of the mouth to open beside the frenulum of the tongue. It runs upwards against gravity.
- Mixed seromucous (thicker) saliva.
Nerves at risk in submandibular gland excision:
| Nerve | Relation | Effect of injury |
|---|---|---|
| Marginal mandibular branch of facial nerve | Runs in the skin flap, superficial to the gland, near the facial vessels (incision placed 3-4 cm below the mandible) | Weak depressor of the lower lip; asymmetric smile |
| Lingual nerve | Deep to the gland; hooked to it by the submandibular ganglion; loops under Wharton's duct | Numb tongue, loss of taste in anterior two-thirds |
| Hypoglossal nerve | Deep, below the gland on hyoglossus | Tongue deviates to the injured side |
Sublingual gland
- Under the floor of mouth mucosa; drains by many small ducts. Source of the ranula.
Salivary stones (sialolithiasis)
| Feature | Submandibular | Parotid |
|---|---|---|
| Share of all stones | About 80% | About 20% |
| Radio-opaque? | Mostly (about 80%) | Mostly radiolucent |
| Why | Thick, mucous, alkaline saliva rich in calcium; long duct running uphill | Watery saliva; strictures more common here |
- Symptoms: painful swelling of the gland at mealtimes ("meal-time syndrome") that settles over an hour or two; may become infected (pus at the duct opening).
- Examination: a stone may be felt bimanually in the floor of mouth.
- Investigations: ultrasound (first line); plain occlusal X-ray shows radio-opaque submandibular stones; sialography (contrast into the duct) shows strictures and stones (never during acute infection); sialendoscopy; CT.
- Treatment:
- Stone in the anterior duct (palpable): intraoral removal by slitting the duct over the stone.
- Small stones: basket retrieval or sialendoscopy; medium ones broken by lithotripsy.
- Stone deep in the hilum or gland with repeated attacks and a damaged gland: excision of the submandibular gland.
Inflammation (sialadenitis)
| Condition | Key features | Treatment |
|---|---|---|
| Mumps (viral parotitis) | Commonest cause of acute painful parotid swelling, usually children; bilateral in most; fever; complications orchitis (adults), pancreatitis, meningitis, deafness | Symptomatic; MMR vaccine prevents |
| Acute bacterial (suppurative) parotitis | Dehydrated, elderly, postoperative patients or a duct stone; tender red swelling, pus from Stensen's duct | Rehydration, oral hygiene, IV antibiotics (Staphylococcus aureus commonest); drain an abscess (ultrasound shows it; fluctuation is late because of the tough fascia) |
| Recurrent parotitis of childhood | Repeated swelling, age 3-6; "snowstorm" sialectasis on sialography | Antibiotics, duct washouts; usually improves by puberty |
| HIV-associated | Painless parotid swelling with multiple lymphoepithelial cysts | Antiretrovirals, aspiration |
| Chronic sialadenitis | Usually submandibular, secondary to stones | Remove stone or gland |
Postoperative acute parotitis is prevented by keeping the patient well hydrated with good oral hygiene; it is a sign of poor fluid management.
Cysts
- Mucocele: small bluish cyst of a minor gland, usually on the lower lip, from trauma. Excise with the underlying gland.
- Ranula: mucous extravasation cyst from the sublingual gland; translucent bluish swelling in the floor of mouth like a frog's belly.
- Plunging ranula: extends through or behind the mylohyoid into the neck as a soft, painless submandibular swelling.
- Treatment: excision of the sublingual gland (with the ranula). Simple incision and drainage leads to recurrence.
Sjogren's syndrome
- Autoimmune destruction of salivary and lacrimal glands by lymphocytes; mostly middle-aged women.
- Primary (dry eyes and mouth alone) or secondary (with RA, SLE, primary biliary cholangitis).
- Dry mouth (xerostomia), dry eyes (keratoconjunctivitis sicca), parotid swelling, dental decay, candidiasis.
- Tests: anti-Ro and anti-La, Schirmer test, labial (lip) gland biopsy shows focal lymphocytic infiltrate.
- Treatment is symptomatic: artificial tears and saliva, fluoride.
- Increased risk of B-cell non-Hodgkin lymphoma (MALT): a new firm or growing parotid swelling needs investigation.
Salivary gland tumours
Where and how likely malignant
| Gland | Share of tumours | Proportion malignant |
|---|---|---|
| Parotid | Commonest site (most tumours) | About 15-20% (80-90% benign) |
| Submandibular | Fewer | About 30-40% (60-70% benign) |
| Sublingual | Rare | About 90% |
| Minor glands (palate commonest) | Some | Most are malignant |
"The smaller the gland, the more sinister the swelling."
Classification (simplified)
| Benign | Malignant (low grade) | Malignant (high grade) |
|---|---|---|
| Pleomorphic adenoma | Acinic cell carcinoma | High-grade mucoepidermoid |
| Warthin tumour (adenolymphoma) | Low-grade mucoepidermoid | Adenocarcinoma |
| Other monomorphic adenomas | Adenoid cystic carcinoma (slow but relentless) | Squamous cell carcinoma, carcinoma ex pleomorphic adenoma |
Benign tumours
| Feature | Pleomorphic adenoma | Warthin tumour |
|---|---|---|
| Frequency | Commonest salivary tumour overall | Second commonest benign parotid tumour |
| Patient | Middle-aged, women slightly more | Older men, smokers |
| Site | Usually superficial lobe, below or in front of the ear (lifts the ear lobe) | Almost only in the parotid tail |
| Feel | Firm, rubbery, lobulated, slow-growing | Soft, cystic, may fluctuate |
| Bilateral | Rarely | About 10% bilateral or multifocal |
| Pathology | Mixed epithelial and myxoid/chondroid stroma; incomplete capsule with pseudopodia | Cystic spaces lined by oncocytic cells with lymphoid stroma |
| Scan | - | Takes up technetium-99m ("hot") |
| Malignant change | Possible (carcinoma ex pleomorphic adenoma) after many years | Essentially none |
Pleomorphic adenoma must not be enucleated. Its capsule is incomplete with finger-like pseudopodia, so shelling it out leaves tumour behind and causes multifocal recurrence. Remove it with a cuff of normal tissue (superficial parotidectomy or careful extracapsular dissection).
Malignant tumours
- Mucoepidermoid carcinoma: the commonest malignant parotid tumour (and commonest salivary malignancy in children); behaviour depends on grade.
- Adenoid cystic carcinoma: commonest malignancy of the submandibular and minor glands; notorious for perineural spread (pain, facial nerve palsy), local recurrence and late lung metastases. Swiss-cheese (cribriform) pattern.
- Acinic cell carcinoma: low grade, may be bilateral.
Clinical signs that a parotid lump is malignant:
- Facial nerve weakness (the most important sign)
- Rapid growth, pain
- Hard, fixed, skin involvement or ulceration
- Neck lymph nodes
- Deep-lobe extension (trismus, parapharyngeal mass)
A benign parotid tumour does not paralyse the facial nerve, however large it becomes. Facial palsy with a parotid mass means malignancy until proven otherwise.
Investigation
- Ultrasound first (is the lump inside the gland?), with ultrasound-guided FNAC or core biopsy.
- MRI (or CT) for deep-lobe tumours, malignant tumours and surgical planning.
- Open (incisional) biopsy is contraindicated: it risks spilling tumour and damaging the facial nerve.
Treatment
| Situation | Operation |
|---|---|
| Benign tumour of superficial lobe | Superficial parotidectomy (or partial/extracapsular dissection by experienced surgeons) |
| Deep-lobe tumour | Total (conservative) parotidectomy, preserving the facial nerve |
| Malignant tumour with nerve not involved | Total parotidectomy keeping the nerve; neck dissection if nodes; radiotherapy for high-grade, close margins, adenoid cystic, or tumours over 4 cm |
| Malignant tumour invading the nerve | Radical parotidectomy (nerve removed) with immediate nerve grafting (great auricular or sural nerve) and neck dissection |
| Submandibular tumour | Excision of the gland (benign) or wide clearance of the submandibular triangle with neck dissection (malignant) |
Finding the facial nerve trunk at parotidectomy:
- Tragal pointer (Conley's pointer): the nerve lies about 1 cm deep and inferior to the tip of the tragal cartilage.
- Upper border of the posterior belly of digastric.
- Tympanomastoid suture (the nerve exits the stylomastoid foramen just deep to it).
- Retrograde: trace a peripheral branch back.
Complications of parotidectomy
| Complication | Points |
|---|---|
| Facial nerve weakness | Usually temporary (neurapraxia), most often the marginal mandibular branch; permanent palsy is uncommon when the nerve is preserved |
| Great auricular nerve numbness | Very common: numb ear lobe (nerve usually divided) |
| Frey's syndrome (gustatory sweating) | Sweating and flushing of the cheek when eating; damaged auriculotemporal parasympathetic fibres regrow into skin sweat glands. Confirmed by the starch-iodine (Minor's) test. Treat with botulinum toxin, antiperspirant; prevented by an SCM or temporalis fascia flap or a barrier membrane |
| Salivary fistula / sialocele | Saliva leaks from the cut gland; usually settles with pressure, aspiration or botulinum toxin |
| Haematoma, infection, hollow cheek, keloid | Less common |
Expect: the commonest salivary tumour (pleomorphic adenoma) and why it recurs after enucleation, Warthin tumour in elderly smokers (bilateral, hot on technetium scan), the commonest malignant parotid tumour (mucoepidermoid), perineural spread of adenoid cystic carcinoma, facial palsy meaning malignancy, the "smaller gland, more malignant" rule, submandibular stones (80%, radio-opaque, mealtime swelling), acute parotitis in the dehydrated postoperative patient, mumps, ranula, Sjogren's with lymphoma risk, structures within the parotid, nerves at risk in submandibular excision, and Frey's syndrome with the starch-iodine test.
Quick revision
- Parotid tumours mostly benign; sublingual and minor gland tumours mostly malignant.
- Pleomorphic adenoma: commonest; pseudopodia; superficial parotidectomy, not enucleation.
- Warthin: old male smokers, bilateral, parotid tail, hot on technetium.
- Mucoepidermoid: commonest parotid cancer; adenoid cystic: perineural spread.
- Facial palsy + parotid lump = malignancy.
- No open biopsy; use ultrasound-guided FNAC or core biopsy.
- 80% of stones in submandibular gland, 80% of these radio-opaque.
- Submandibular excision risks marginal mandibular, lingual and hypoglossal nerves.
- Frey's syndrome: gustatory sweating, starch-iodine test, botulinum toxin.
Written by The House Job from standard references (Bailey & Love).
FAQ
Why does a pleomorphic adenoma recur after simple enucleation?
Its capsule is incomplete and tumour sends finger-like pseudopodia into surrounding gland, so shelling it out leaves tumour cells behind that grow back as multiple nodules.
Why are stones more common in the submandibular gland?
Its saliva is thicker and richer in calcium and mucus, and Wharton's duct is long and runs upwards against gravity, so saliva stagnates.
What does facial nerve weakness with a parotid lump mean?
It strongly suggests a malignant tumour invading the nerve, because benign tumours push the nerve aside rather than paralysing it.
What is Frey's syndrome?
Sweating and flushing over the parotid area while eating, caused after parotidectomy by parasympathetic fibres of the auriculotemporal nerve regrowing into skin sweat glands.
What is a plunging ranula?
A mucus collection from the sublingual gland that tracks through or behind the mylohyoid into the neck; it is cured by removing the sublingual gland.