Salivary gland disorders, pathology

Question 1

Aplasia

Answer 1

• Failure to develop normally
• Of salivary glands is very rare. It may occur as an isolated event or as part of a hereditary syndrome (e.g Down syndrome)

Question 2

Atresia

Answer 2

• Failure to be tubular
• of ducts is also very uncommon. Submandibular duct most often affected when it does occur

Question 3

Heterotopic salivary tissue

Answer 3

Can be found at various sites in head and neck

Question 4

What is a mucocoele ?

Answer 4

Is a cystic cavity filled with mucus

Question 5

What are the two mucocoele ?

Answer 5

• Extravasation mucocoele (also called mucous extravascation cyst)
• Retention mucocoele (also called mucous retention cyst)

Question 6

Extravasation Mucocoele

Answer 6

Clinical Features/Aetiology

• Presents as a bluish or transparent swelling
• Most commonly affects minor glands especially in the lower lip
• Occurs over a wide age range but most frequently seen in children and young adults
• Asymptomatic
• May discharge only to re-form
• Typically history of trauma associated with the lesion
• Due to ruptured duct with leakage of saliva into surrounding connective tissue
• Leaked saliva elicits an inflammatory reaction

Question 7

Mucous Extravasation cyst

Answer 7

Histopathology
- Lesion appears as a cystic cavity filled with mucin in connective
- Mucin is surrounded by inflamed granulation tissue, typically with lots of macrophages
- Not classed as a true cyst as no epithelial lining

Question 8

Mucous retention cyst (clinical features/aetiology)

Answer 8

• Similar appearance to but less common than extravasation cyst
• Rare on lower lip
• Can affect the major and minor glands
• Represents cystic dilatation of a duct typically due to obstruction

Question 9

Mucous retention cyst (Histopathology)

Answer 9

• Mucin retained within a dilated duct
• Cyst lining is epithelial lining of the duct
• As saliva is retained within the duct and doesn’t escape, there is much less inflammation

Treatment
- Excision

Question 10

Ranula

Answer 10

• Painless soft bluish swelling in floor of mouth
  Clinical features
• Presents as painless soft bluish swelling in floor of mouth
• Unilateral
• 2-3 cm in size
• It is an uncommon form of mucous extravasation cyst arising from sublingual gland
• A ‘plunging ranula’ arises when the mucin passes through and develops below mylohyoid as swelling in neck
  Treatment
• Drainage of the cystic cavity and removal of sublingual gland

Question 11

Acute Bacteria Sialadenitis

Answer 11

• The most common causes are bacterial or viral infection
  Clinical features
• Parotid most often affected
• Decreased salivary flow is major predisposing factor
• Patients present with pain, swelling, tenderness, exudation of pus. There may be redness of overlying skin
• Associated bacteria frequent Staphylococcus aureus, streptococci and oral anaerobes
  Treatment
• Appropriate antibiotics after culture/sensitivity testing

Question 12

Chronic Bacterial sialadenitis

Answer 12

Clinical features
- Usually secondary to duct obstruction
- Obstruction most frequently caused by stones/salivary calculi/mucous plugs (parotid)
- Submandibular gland most often affected
- Typically unilateral
- May be asymptomatic or may be intermittent painful swelling which is usually mealtime related
Treatment
- The gland may recover from mild sialadenitis if the associated obstruction can be removed
- If more extensive sialadenitis, the obstruction can be removed
- If more extensive sialenitis, the obstruction and gland requires to be excised

Question 13

Salivary calculi (Sialoliths/stones)

Answer 13

• Submandibular gland most commonly affected
• Calculi mainly occur in adults
• Caused by mineralisation of phosphates from supersaturated saliva being deposited around a central nidus of cell debris
• Calculi may form within ducts in the gland or in the main excretory duct
• Calculi vary in size, may be more than one, may be round or avoid, rough or smooth and usually yellowish in colour
• Bacteria often grow on the stone surface and elicit an inflammatory response
• No symptoms until stone cause obstruction
• Typically unilateral swelling/pain, often at mealtimes
• Calculi do not cause dry mouth however factors which icnrease saliva saturation e.g. dry mouth, dehydration predisposes to stones
• Treatment varies depending on size and location of stones
• May be possible to remove or breakdown some stones. Alternatively it may be necessary to remove the gland, especially if it has become very damaged by longstanding infection

Question 14

Mumps (Viral Sialadenitis)

Answer 14

• Acute, contagious infection caused by paramyxovirus
• Spreads via saliva
• Mumps causes painful swelling of parotids and other exocrine glands
• Patients also present with fever headache, malaise

Question 15

Necrotising Sialometaplasia (Clinical features)

Answer 15

• It is more common in males than females
• More frequently seen in older patients and in smokers
• It mainly affects minor salivary glands, especially those in the hard palate
• Presents as a large, deep ulcer
• May be painful
• Slow to heal, often takes several weeks
  Treatment
  None required, it slowly resolves itself. Biopsy is usually curative

Question 16

Sjogren’s syndrome

Answer 16

• Is an autoimmune disease of unknown cause
• characterised by lymphocytic infiltration and acinar destruction of lacrimal and salivary glands (and other exocrine glands)
  Clinical features
• Onset middle age
• Females are much more commonly affected than males
• Systemic symptoms including fatigue, joint pain, peripheral neuropathy
• Complications of dry mouth - caries, periodontal disease, difficulty with swallowing, speech, taste, predisposition to infections
• There may be swelling of salivary glands, esp parotids
• Eye problems due to dry eyes
• Connective tissue disease in 2 sjogren’s syndrome

Question 17

What are the two forms of sjogren’s syndrome that exist?

Answer 17

• Primary sjogren’s syndrome
• Secondary Sjogren’s syndrome

Question 18

Primary sjogren’s syndrome

Answer 18

Patients have dry eyes and/or a dry mouth with no associated connective tissue disease

• Increased risk of developing lymphoma in affected glands

Question 19

Secondary sjogren’s syndrome

Answer 19

Patients have dry eyes and/or, a dry mouth and a connective tissue disease, e.g. rheumatoid arthritis

Question 20

What are the diagnostic tests for sjogren’s syndrome?

Answer 20

• One test is a labial gland biopsy taken from the lower lip. The biopsy aims to sample 5-8 minor glands
• The biopsy is examined, in particular noting focal periductal collections of 50 or more lymphocytes
• The number of foci of one or more focus of 50 > lymphocytes in 4mm^2 of salivary tissue is counted
• A score of more or more is suggestive of sjogren’s syndrome
  Management
• Multidisciplinary
• Systemic symptoms e.g. joint pain, fatigue normally assessed and managed by rheumatology
• Opthalmology for eye symptoms
• Dry mouth - as for other causes of dry mouth - stimulation and/or replacement
• Some saliva replacement products specifically licensed for use in sjorgren’s
• The systemic acetyl choline esterase inhibitor pilocarpine may be prescribed by specialists to stimulate saliva production in patients with sjogren’s
• caries prevention

Question 21

Sialadenosis

Answer 21

• This is a non-inflammatory, non-neoplastic, bilateral, symmetrical swelling of salivary glands
• Predominantly parotid glands affected
• Painless
• Associated with malnutrition, anorexia, bulimia, alcoholism, diabetes mellitus, certain drugs and hormonal disturbances
• Results in hypertrophy of serous acini
• Not entirely understood but changes likely due to salivary gland innervation problem secondary to peripheral autonomic neuropathy

Question 22

Diagnosis of salivary gland tumours

Answer 22

The clinical and radiological findings are very important in the diagnosis of salivary gland tumours
Tissue may be obtained to attempt to confirm a definitive diagnosis by various methods

• Fine needle aspiration (FNA) - a needle is used to aspirate cells from the lesion and the cell features examined
• Core biopsy - a larger hollow needle is used to remove a core of tissue
• Open biopsy - a surgical incision is made then an incisional biopsy of the lesion taken
• ## Excision - all of the tumour is removed for diagnosis and treatment

Question 23

What are the current WHO classification of salivary gland tumours

Answer 23

1) Malignant tumours
2) Benign tumours
3) Non-neoplastic epithelial lesions
4) Benign soft tissue lesions
5) Haematolymphoid tumours

Question 24

Mucoepidermoid carcinoma

Answer 24

• Most frequently affects the parotids but can occur in others including minor glands
• Can be seen in children and young adults
• More common in females than males
• It is locally invasive, it can recur and can metastasise
  Treatment
• Complete excision of the tumour

Question 25

Pleomorphic adenoma

Answer 25

• Most common type of all salivary gland tumours
• Most frequently occurring of 12 primary benign epithelial tumours
• Slightly more common in females than males
• Occur at any age, peak incidence 5th and 6th decades
• Benign, painless, slow growing, ‘rubbery’ lump
• Usually solitary although recurrences may be multifocal
• Most are associated with gene rearrangements in PLAG1 or HMGA2
  Treatment
• Complete excision. If incompletely excised pleomorphic adenoma has a high recurrence rate
  Malignant transformation can occur in pleomorphic adenoma, usually in long standing lesions. Transformed tumours, called carcinoma ex pleomorphic adenoma, are typically high grade malignancies with poor prognosis