Salivary glands 1

Question 1

What are the functions of the facial nerve?

Answer 1

Motor and sensory branches

Controls the muscles of facial expression

Taste sensation from anterior 2/3 of tongue (via chorda tympani)

Supplies parasympathetic fibres to the submandibular gland & sublingual glands via the chorda tympani. This increases saliva flow from the glands.

It also supplies parasympathetic innervation to the nasal mucosa and the lacrimal gland via the pterygopalatine ganglion. 

Question 2

What are the branches of the facial nerve & which structures do they innervate?

Answer 2

The facial nerve pierces the parotid gland but doesn’t innervate it.

The extra-cranial terminal branches are:

Temporal branches: supply the frontalis, orbicularis oculi and corrugator supercilii muscles.

Zygomatic branches: supply the orbicularis oculi muscle.

Buccal branches: supply the orbicularis oris, buccinator and zygomaticus muscles.

Marginal mandibular branch: supplies the depressor labii inferioris, depressor anguli oris and mentalis muscles.

Cervical branch: supplies the platysma muscle in the neck.

Question 3

What can cause lumps in the neck?

Answer 3

Lymph nodes – can become enlarged due to an infection (reactive), metastatic cancer, lymphoma (cancer of lymph nodes)

Salivary glands- whole gland swollen, sialosis (inflammation of saliva gland), obstruction, infection.

Within the gland – tumour, stone, lymph node

Outside the gland – stone, lymph node, parotid duct stones in cheek, submandibular stones in floor of mouth.

Thyroid – midline at base of neck which moves when swallowing. Covers thyroid cartilage.

Developmental cysts – thyroglossal duct cysts

Other tumours

Question 4

Describe the lymphatic drainage of the head and neck.

Answer 4

IO pathology tends to drain to submandibular and submental nodes first.

Lump in submandibular gland – look inside the mouth for lesions.

Parotid and submandibular glands also contain lymph nodes.

Scalp & skin at back of neck – drains into parotid lymph nodes in and around the gland.

Parotid lump – check scalp, skin of face and back of neck for infections / tumours causing the lymphadenopathy

Question 5

List the different salivary glands.

Answer 5

Major glands: parotid (EO structure), submandibular (partly IO and partly EO – wraps itself around back of mylohyoid muscle), sublingual (IO)

Parotid gland has two lobes: superficial lobes and deep lobes in relation to facial nerve.

Minor glands: palate, lips (all IO)

Question 6

Which examinations are carried out for SG?

Answer 6

EOE, IOE
If swelling present, carry out bimanual palpation of submandibular gland
Facial nerve assessment
Check tonsillar fossa

Question 7

Describe the assessment of SG swelling in detail.

Answer 7

EOE – stand behind pt. Pt should be relaxed sat up or laying back in chair.

Systematic approach to LN assessment: Submandibular -> submental -> Sternocleidomastoid -> supraclavicular -> posterior triangle (trapezius then back of head)

IOE – systematic: ST, BM, gingivae: palatal, lingual and buccal. Dorsal, ventral and lateral surface of tongue, floor of mouth, hard and soft palate. Salivary glands – saliva from parotid ducts & submandibular ducts via buccal mucosa.

Quantity of saliva & quality of saliva – clear?

Challacombe scale for xerostomia

Duct orifices: Pus? Due to infection, Stones -> may get mealtime symptoms.

Bimanual palpation of submandibular gland (put finger inside the mouth on one side of tongue back to wisdom tooth & gently push down. Other hand feels for the submandibular gland for swelling, lump, stones)

Facial nerve assessment (where lumps in parotid gland observed)

Raise eye brows against resistance, close eyes as tight as possible to resistance, puff out cheeks to resistance, purse lips, bear teeth. Ask if there has been a change to taste / hearing sounds louder than usual. Facial weakness? – may be due to parotid swelling. Malignant tumours disrupting function of facial nerve on that side.

Parotid gland swelling - checking the tonsillar fossa (tumours may extend to oropharynx.

Question 8

If a patient has a neck or salivary gland lump for >3 weeks. What is the course of action?

Answer 8

Urgent 2WW referral (suspected cancer)

Question 9

What happens when a patient is referred for 2WW?

Answer 9

Clinical assessment: site, size, attachment (deep structures/skin), MH, fitness for surgery.

Radiological: USS, MRI, CT (if tumour suspected)

Pathology: biopsy techniques (for diagnosis) – incisional biopsy or fine needle aspiration cytology or core biopsy.

Question 10

How are Salivary gland tumours described?

Answer 10

Tumours of major SG (parotid, submandibular and sublingual) and minor SG

Parotid gland tumours are more commonly affected (60-70%) -> then submand -> then sublingual -> then minor glands

However, malignancy more likely in minor glands -> then sublingual -> submand -> parotid (more likely to benign).

Question 11

Some tumours can be benign (don’t metastasize) but can be locally aggressive. E.g. basal cell carcinoma. Why is this harmful?

Answer 11

If not controlled, will recur and destroy local tissues. Need a good margin around the carcinoma when excised.

Question 12

What is an adenolymphoma? (Warthin’s tumour)

Answer 12

Benign tumour. Common. Often in parotid gland – in lower pole. Lifts lobe of ear up. Soft, smooth, fluid filled lump. Mobile. Not fixed to skin or deep tissues.

M>F ages 50-70 yrs old. Smokers

Multifocal (will have more than one tumour in same gland) or may be bilateral - have tumour on both sides.

Question 13

What is a pleomorphic salivary adenoma (PSA)?

Answer 13

Most common salivary gland tumour.

Benign (10% recurrence rate – higher if outer capsule broken)

Often in parotid gland – in lower pole. Lifts lobe of ear up. Firmer, smooth, fluid filled lump. Mobile. Not fixed to skin or deep tissues. Slow growing but needs excision to remove as has risk of malignancy.

Surrounded by thick capsule – good because it makes surgery easier. However, breach in capsule allows tumour tissue within capsule to leak out into wound = increasing risk of tumour coming back.

80% of parotid tumours. 50% of other gland tumours.

Epidemiology: F>M, ages 20-60 yrs.

Question 14

Pleomorphic salivary adenomas have a small chance of malignant transformation. True / False?

Answer 14

True – also known as ‘Carcinoma arising in pleomorphic salivary adenoma or Carcinoma ex PSA’

Question 15

Describe a carcinoma ex PSA.

Answer 15

Rate: 1% per year

Approx 1% of parotid tumours

Very aggressive, rapid growth, poor prognosis

Can result in facial weakness

Skin redness & ulceration.

Question 16

What is an Adenoid-cystic carcinoma?

Answer 16

More aggressive tumour that can affect any gland (e.g. breast/skin sweat glands/nose) – difficult to control. More common in other glands.

Makes up 10% of parotid tumours.

Less common than PSA.

Peri-neural spread – wrapped around microscopic nerves and travels up to spine/head/brain.

More likely to produce facial weakness

Question 17

Give examples of salivary gland tumours with variable characteristics.

Answer 17

Mucoepidermoid tumour

Acinic cell tumour

Question 18

How are SG tumours assessed and staged?

Answer 18

2WW referral. Assessment and imaging.

Diagnosis – clinical suspicion, biopsy

Staging: MRI, CT. TNM staging of malignant tumours for oral cancer.

    T – size 

    N- degree of spread to regional LN 

    M- metastasis

Question 19

How are SG tumours managed?

Answer 19

Surgery – primary tumour removed and regional LN sampled

Superficial parotidectomy, total parotidectomy

Radiotherapy – primary site and regional LN

Chemotherapy – in addition to radiotherapy to improve outcomes

Reconstruction to improve patients QoL to avoid OAF.

Question 20

What are the complications of salivary gland surgery?

Answer 20

Skin numbness

Facial nerve weakness – mostly recovers but no guarantee.

Scarring (heals well but not always – keloid scar not aesthetic)

Sialocoele – collection of saliva under skin. When it bursts it can produce a fistula - seeps through skin.

Frey’s syndrome (Gustatory sweating)

Question 21

What is Frey’s syndrome (Gustatory sweating) ?

Answer 21

Neurological disorder caused by damage/trauma/surgery to or near parotid glands.

Nerves supplying glands damaged = these nerves try to rejoin and nerve fibres from saliva gland end up communicating with nerve fibres supplying sweat glands.

Symptoms: Redness, sweating on skin of cheek area adjacent to ear.

Starch iodine test can be used to detect it – blue/black stain formed.

Easy to treat with botox (targets Acetylcholine at nerve synapses preventing its’ release).