Salivary Glands

Question 1

What is the structure of the parotid gland?

Answer 1

They are divided into superficial and deep parts, which are separated by the facial nerve and its divisions

They are surrounded by a connective tissue capsule called the investing layer of the deep cervical fascia

Question 2

What is the name of the parotid duct?

Answer 2

Stenson’s duct

This pierces the buccinator and drains into the oral cavity next to the 2nd upper molar

Question 3

What structures lie within the parotid gland?

Answer 3

Lateral to medial:
Facial nerve
Retromandibular vein
External carotid artery
Parotid lymph nodes

Question 4

What are the tributaries of the retromandibular vein?

Answer 4

Maxillary vein
Superficial temporal vein

Question 5

What is the blood supply to the parotid gland?

Answer 5

Posterior auricular and superficial temporal branches of the external carotid artery

Question 6

What is the autonomic innervation of the parotid gland?

Answer 6

Parasympathetic supply from the glossopharyngeal nerve -> otic ganglion -> auriculotemporal nerve

Sympathetic innervation from the superior cervical ganglion

Question 7

What is the name of the submandibular duct?

Answer 7

Wharton’s duct

This opens just laterally to the frenulum

Question 8

What is the blood supply to the submandibular gland?

Answer 8

Facial and lingual branches of the external carotid artery

Question 9

Where is the incision made for submandibular gland surgery?

Answer 9

Tranverse line 3 cm below the lower border of the mandible

This avoids damage to the marginal mandibular nerve

Question 10

Which structures are at risk from submandibular gland surgery

Answer 10

Marginal mandibular nerve
Lingual nerve
Hypoglossal nerve
Nerve to the mylohyoid

Facial artery and vein

Question 11

What is the parasympathetic nervous supply of the submandibular gland?

Answer 11

Fibres in the chorda tympani branch of the facial nerve which then join the lingual nerve.

These synapse in the submandibular ganglion.

Question 12

Where are most salivary gland tumours found?

Answer 12

80% are parotid (80% benign)
15% are submandibular (50% benign)
5% are sublingual (20% benign)

Question 13

What are the different salivary gland tumours?

Answer 13

Benign:
Pleomorphic adenoma (most common salivary neoplasm)
Warthin’s tumour

Malignant:
Mucoepidermoid carcinoma (most common malignancy)
Adenoid cystic carcinoma
Acini cell carcinoma
Adenocarcinomas and squamous cell carcinomas

Question 14

How are pleomorphic adenomas treated?

Answer 14

Superficial parotidectomy

Question 15

What are the risk factors for salivary gland tumours?

Answer 15

Local radiation
EBV infection
Smoking (specifically linked to Warthin’s tumours)
Genetics

Question 16

How do salivary gland tumours generally present?

Answer 16

Slow growing and painless masses

If malignant, facial nerve palsies, local invasion and overlying skin changes are more likely

Question 17

Which tumour is associated with facial nerve palsy?

Answer 17

Adenoid cystic carcinoma

(Causes perineural invasion)

Question 18

How to investigate salivary gland tumours?

Answer 18

Bedside, bloods, imaging (ultrasound, FNAC, staging CT neck + thorax, MRI to assess for neural invasion)

Question 19

How to manage salivary gland tumours?

Answer 19

MDT

Surgical:
Resection +/- lymph node dissection +/- reconstruction

Surgery Options:
Superficial parotidectomy - facial nerve left in place
Total conservative parotidectomy - saves the facial nerve
Radical parotidectomy - sacrifices the facial nerve
Extended parotidectomy - involves surrounding local structures

Non-Surgical:
Adjuvant radiotherapy for high grade disease, perineurial invasion, lymph node spread and residual disease

These tumours don’t usually respond to chemotherapy

Question 20

What are the complications of salivary gland surgery?

Answer 20

Early:
Haematoma (expanding haematomas in the neck can cause local compression)
Facial nerve injury
Marginal mandibular nerve injury

Late:
Frey’s syndrome after a parotidectomy (damage to the auriculotemporal nerve followed by inappropriate regeneration -> gustatory sweating and flushing)
Salivary gland fistulation