Salivary Gland Disorders

Question 1

What are the salivary glands?

Answer 1

Parotid
Submandibular
Sublingual
Minor salivary glands

Question 2

What is the parotid gland

Answer 2

Largest salivary glands
Mainly serous acini

Location:
Posterior aspect of masseter, before ear
Wraps around posterior border of mandible
Divided by facial nerve into deep and superficial lobes
Small ducts coalesce to form Stenson’s duct (6cm in length, pierces buccinator to exit adjacent to max 2nd molar)

Stimulated by parasympathetic fibers from IX

Question 3

What is the submand gland

Answer 3

Size of a walnut, in submand triangle of neck
Partly superficial and partly deep to mylohyoid
Whartons duct opens into floor of mouth lateral to lingual frenum
Lingual nerve loops under Whartons duct from lateral to medial
Produces mixed serous and mucous saliva

Innervated by VII through chorda tympani

Question 4

What is the sublingual gland

Answer 4

Size of an almond
Lies on superior surface of mylohyoid
8-20 ducts open directly into floor of mouth or submand duct

Produces mainly mucous saliva

Innervated by VII through chorda tympani

Question 5

What are the minor salivary glands

Answer 5

Numerous scattered in buccal, labial, lingual mucosa, soft palate, lateral hard palate, floor of mouth

Each cluster has an individual duct leading to the surface of the mucosa

Keeps all mucosa moist with mucous saliva

Question 6

Diagnostic imaging of salivary glands

Answer 6

Plain films
Sialography
CT scans
MRI

Question 7

Salivary gland infection (sialadenitis) causes

Answer 7

Can be acute or chronic
Viral, bacterial, fungal, mycobacterial
> if bacterial often staph aureus
May or may not be related to obstruction
Parotitis often related to changes in fluid balance, e.g. dehydration

Question 8

What is viral parotitis

Answer 8

Mumps

Acute infection
Paramyxovirus
Non suppurative, communicable disease (via urine, saliva or respiratory droplets)
Common in 3-8yo
Painful swelling of one or both parotid/submand glands
Pyrexia, chills, headaches
Symptoms begin 16-18 days after exposure, lasting 5-12 days
Contagious from 1 day before symptoms to 14 days after resolution

Complications include meningitis, pancreatitis, nephritis, oopheritis, orchitis, sterility in males

Mx: prevention via vaccination (MMR, effectiveness 75-95%), symptomatic care, analgesics, antipyretics, hydration

Question 9

Acute bacterial sialadenitis

Answer 9

Parotitis

Most arise from blocked ducts due to stones, or decreased salivary flow rate due to dehydration, debilitation, drugs, Sjogrens etc

Retrograde spread of bacteria through the ductal system

Mx: symptomatic, supportive care - IV fluid hydration, analgesics. Culture causative organism to investigate cause, administer appropriate antibiotics

Question 10

Types of obstructive salivary gland diseases

Answer 10

Sialolithiasis
Mucocele
Ranula

Question 11

What is sialolithiasis

Answer 11

Calcified structures (from calcium salt deposition around a nidus of debris) develop within ductal system

Most common in young and middle aged adults

More commonly submand gland

Can cause recurrent sialadenitis
Larger stones can cause obstruction of salivary flow, episodic pain esp at mealtimes

Mx: removal of stone, may require excision of affected gland if recurrence or stone v deep in gland. Can also do sialoendoscopy to remove smaller stones or laser-fragmented larger stones, but v technically challenging

Question 12

What is a mucocele

Answer 12

Mucous extravasation cyst

Common lesion of oral mucosa, esp children and young adults
Results from traumatic rupture of salivary duct
Spillage of mucin into surrounding soft tissues, presenting as a bluish fluctuant lesion
Often lower lip, sometimes ventral surface of tongue or cheek
May burst and reform

Question 13

What is a ranula

Answer 13

A mucocele on the floor of the mouth
Dome-shaped bluish fluctuant swelling
Mucin spillage from sublingual gland ducts, minor salivary gland ducts or Wharton’s duct
Often in children or young adults

Tx: marsupialisation

Often a mucous RETENTION cyst

Question 14

What is neoplasm of the salivary glands

Answer 14

Swelling increasing in size
Can be painless or have a dull ache
Firm to rubbery texture

7% of HN tumours
Parotid tumours 9x more common than submand, 100x more common than sublingual
Parotid 80% benign (mostly pleomorphic adenoma)
Submand 50% malignant
Sublingual 65-88% malignant

No gender predilection

Question 15

Examples of benign salivary gland tumours

Answer 15

Pleomorphic adenoma
Warthin tumour (papillary cystadenoma lymphomatosum)
Basal cell adenoma

Question 16

Examples of malignant salivary gland tumours

Answer 16

Mucoepidermoid carcinoma
Adenoid cystic carcinoma
Polymorphous low grade adenocarcinoma

Question 17

What is pleomorphic adenoma

Answer 17

Most common salivary gland neoplasm
4th-6th decades
F>M
Slow growing painless mass
Parotid? Mostly in superficial lobe
Minor salivary gland? Mostly lateral palate, submucosal
Rarely can transform into carcinoma ex-pleomorphic adenoma

Question 18

Histology of pleomorphic adenoma

Answer 18

Mixture of epithelial, myoepithelial and stromal components

Epithelial nests, sheets, ducts, trabeculae
Myxoid, chondroid, fibroid and osteoid stroma
No true capsule, may have incomplete connective tissue capsule

Question 19

Tx of pleomorphic adenoma

Answer 19

Complete surgical excision of affected salivary gland

Avoid enucleation and tumour spill

Question 20

What is warthin tumour

Answer 20

Papillary cystadenoma lymphomatosum

Etiology unknown but strong association with smoking
Benign tumour found only in parotid glands
60-70yo
No gender predilection
Slow growing, painless tumour

Question 21

What is mucoepidermoid carcinoma

Answer 21

Most common salivary gland malignancy
5-9% of salivary neoplasms
Most often parotid
F>M, 3rd-8th decades, peak in 5th decade

Low grade: slow growing painless mass
High grade: rapidly enlarging, may have pain
Well circumscribed to partially encapsulated to unencapsulated
Solid tumour with cystic spaces

Question 22

Histology of mucoepidermoid carcinoma

Answer 22

Low grade: mucus cell > epidermoid cells, prominent cysts, mature cellular elements

Intermediate grade: mucus = epidermoid cells, fewer and smaller cysts, increasing pleomorphism and mitotic figures

High grade: epidermoid > mucus cells, solid tumour cell proliferation, can be mistaken for SCCA

Question 23

Tx of mucoepidermoid carcinoma

Answer 23

Influenced by site, stage and grade

Stage I/II = wide local excision

Stage III/IV = radical excision, may have neck dissection and post op radiation therapy

Question 24

What is adenoid cystic carcinoma

Answer 24

Overall 2nd most common salivary gland malignancy
50% in parotid, 50% in minor salivary glands
M>F, 5th decade

Slow growing enlarging mass
Dull pain, paresthesia, facial weakness/paralysis

Question 25

Histology of ACC

Answer 25

Cribriform pattern

Infiltrative proliferation of basaloid cells

Perineural invasion

Question 26

Tx of ACC

Answer 26

Complete local excision
Tendency for perineural invasion, may have to sacrifice facial nerve
Postop radiotherapy

Question 27

Prognosis of ACC

Answer 27

42% local recurrence rate
Distant metastasis to lung
5y survival 75%, 20y survival 13%