Salivary gland disorders, pathology and presentation Flashcards
What is aplasia?
failure to develop normally
- aplasia of salivary glands is very rare. It may occur as an isolated event or as part of a hereditary syndrome
What is atresia?
failure to be tubular
- atresia of ducts is also very uncommon
What duct is most often affected when atresia does occur?
submandibular duct
What is a mucocoele?
a cystic cavity filled with mucous
What are the 2 types of mucocoele?
- extravasation mucocoele (also called mucous extravasation cyst)
- retention mucocoele (also called mucous retention cyst)
How does an extravasation mucocoele present?
as a bluish or transparent swelling
Where do extravasation mucocoeles most commonly affect?
minor glands especially in the lower lip
What age range do extravasation mucocoles occur in?
a wide age range but most frequently seen in children and young adults
Are extravasation mucocoeles symptomatic?
no, asymptomatic
What is typically associated with extravasation mucocoeles?
typically history of trauma associated with the lesion
What causes an extravasation mucocoele?
- due to ruptures duct with leakage of saliva into surrounding connective tissue
- leaked saliva elicits an inflammatory reaction
What is the histopathology of a mucous extravasation cyst?
- lesion appears as a cystic cavity filled with mucin in connective tissue
- mucin is surrounded by inflamed granulation tissue, typically with lots of macrophages
Why are mucous extravasation cysts not classed as true cysts?
no epithelial lining
What is the treatment of extravasation mucocoeles?
removal of all of the mucocoele (excision) together with the associated ruptured duct and gland where possible to prevent recurrence
What is the appearance of a mucous retention cyst?
similar appearance to a extravasation cyst, but less common
(a bluish or transparent swelling)
What can mucous retention cysts affect?
can affect the major and minor glands
- rare on lower lip
What does a mucous retention cyst represent?
represents cystic dilation of a duct typically due to obstruction
What is the histopathology of a mucous retention cyst?
- 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
Why is there less inflammation from a mucous retention cyst than from a extravasating cyst?
it is the leaked saliva that causes inflammation
- saliva does not leak from a mucous retention cyst but does from an extravasating cyst
What is the treatment for a mucous retention cyst?
excision
How does a ranula present?
- presents as a painless soft bluish swelling in floor of mouth
- unilateral
- 2-3cm in size
What causes a ranula?
it is an uncommon form of mucous extravasation cyst arising from sublingual gland
What is a ‘plunging ranula’?
arises when the mucin passes through and develops below mylohyoid as swelling in neck
What is the treatment of a ranula?
drainage of the cystic cavity and removal of sublingual gland
What is sialadenitis?
inflammation of salivary glands
What are the most common causes of sialadenitis?
bacterial or viral infection
What gland is most often affected by acute bacterial sialadenitis?
parotid
What is a major predisposing factor of acute bacterial sialadenitis?
decreased salivary flow
How do patients with acute bacterial sialadenitis present?
- with pain, swelling, tenderness, exsudation of pus
- there may be redness of overlying skin
What are bacteria frequently associated with acute bacterial sialadenitis?
S. aureus, streptococci, and oral anaerobes
What is the treatment for acute bacterial sialadenitis?
appropriate antibiotics after culture/sensitivity testing
What is chronic bacterial sialadentitis usually secondary to?
duct obstruction
What is duct obstruction more frequently caused by?
stones/salivary calculi/mucous plus (parotid)
What gland is most often affected by chronic bacterial sialadenitis?
submandibular
What are the symptoms of chronic bacterial sialadenitis?
may be asymptomatic or may be intermittent painful swelling which is usually mealtime related
- typically unilateral
What gland is most commonly affected by salivary calculi?
submandibular
What is salivary calculi caused by?
mineralisation of phosphates from supersaturated saliva being deposited around a central industry of cell debris
Where may calculi form?
within ducts in the gland or in the main excretory duct
- mainly occur in adults
What is the appearance of salivary calculi?
calculi vary in size, may be more than one, may be round or ovoid, rough or smooth, and usually yellowish in colour
What often grows on the surface of salivary calculi?
bacteria, which can elicit an inflammatory response
What are the symptoms of salivary calculi?
- no symptoms until stone causes obstruction
- typically unilateral swelling/pain, often at mealtimes
Do salivary calculi cause dry mouth?
no, however factors such as dry mouth and dehydration can predispose someone to stones
What does treatment of salivary calculi depend on?
treatment varies depending on size and location of stones
What are the treatment options for salivary calculi?
- 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
What is the histopathology of chronic bacterial sialadenitis?
- the salivary acini become atrophic and are replaced by fibrous scar tissue
- the salivary ducts within the gland become dilated and there is often hyperplasia of the duct epithelium
- a chronic inflammatory infiltrate with predominantly plasma cells and lymphocytes is seen within the gland
What may progressive chronic inflammation result in?
almost complete replacement of salivary parenchyma by fibrous tissue. This can result in a firm mass within the gland which may be mistaken for a neoplasm
What is the treatment for chronic bacterial sialadenitis?
- the gland may recover from mild sialadenitis if the associated obstruction can be removed
- if more extensive sialadenitis, the obstruction and gland requires to be excised
What is mumps (viral sialadenitis)?
- acute, contagious infection caused by paramyxovirus
- spreads via saliva
What does mumps cause?
- painful swelling of parotids and other exocrine glands
- patients also present with fever, headache and malaise
What are some significant complications of mumps?
orchitis, oophoritis, nephritis
What is HIV-associated salivary gland disease?
may be the first clinical sign of HIV infection
What does HIV-associated salivary gland disease cause?
- swelling of major glands (most frequently parotid) and may be bilateral
- gland swelling is occasionally painful and soft to palpate
- multiple cysts are seen on imaging of the glands
What does the histopathology of HIV-associated salivary gland disease show?
- histopathology of glands shows multiple large cysts and dense lymphoid tissue
- the features are suggestive but NOT definitively diagnostic
What are the clinical features of necrotising sialometaplasia?
- more common in males than females
- more frequently seen in older patients and smokers
- 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
What is the aetiology of necrotising sialometaplasia?
uncertain but it likely arises due to ischaemia or infarction secondary to trauma
Why are biopsies of necrotising sialometaplasia often taken?
the appearance of the slow healing ulcers are suspicious for oral cancer or a salivary gland cancer
What does the histopathology of necrotising sialometaplasia show?
- features include necrosis of salivary acini, inflammation and hyperplasia/metaplasia of salivary ducts
- the changes in the duct epithelium can be mistaken for cancer too
What is the treatment for necrotising sialometaplasia?
none required, slowly resolves itself, biopsy is usually curative
What is Sjögren’s syndrome?
an autoimmune disease of unknown cause characterised by lymphocytic infiltration and acinar destruction of lacrimal and salivary glands (and other exocrine glands)
How do patients with Primary Sjögren’s syndrome present?
patients have dry eyes and/or a dry mouth with no associated connective tissue disease
How do patient’s work Secondary Sjögren’s syndrome present?
patients have dry eyes and/or a dry mouth and a connective tissue disease e.g. Rheumatoid arthritis
Who does Sjögren’s syndrome affect?
- onset of Sjögren’s syndrome is in middle age
- females are much more commonly affected than males
What do systemic symptoms of Sjögren’s syndrome include?
fatigue, joint pain, peripheral neuropathy
What are the complications of dry mouth (caused by Sjögren’s syndrome)?
caries, periodontal disease, difficulty with swallowing, speech, taste, predisposition to infection
Other than dry mouth, what issues can be caused by Sjögren’s syndrome?
- there may be swelling of salivary glands, esp. parotids
- eye problems due to dry eyes
- connective tissue disease in secondary Sjögren’s syndrome
- patients with primary sjögren’s syndrome have an increased risk of developing lymphoma in affected glands
What is sialedenosis?
- a non-inflammatory, non-neoplastic, bilateral, symmetrical swelling of salivary glands
- predominantly parotid glands affected
- painless
What is sialedenosis associated with?
malnutrition, anorexia, bulimia, alcoholism, diabetes mellitus, certain drugs and hormonal disturbances
What does sialadenosis result in?
hypertrophy of serous acini
What percentage of salivary gland tumours account in the minor salivary glands?
15-20%
What percentage of major salivary gland tumours occur in the parotid?
90%
What percentage of minor salivary gland tumours arise in the palate?
55%
What percentage of minor salivary gland tumours arise in the upper lip?
20%
What methods of biopsy can be used in the diagnosis of salivary gland tumours?
- fine needle aspiration (FNA)
- core biopsy
- open biopsy
- excision
What are the current categories in the WHO classification of salivary gland tumours?
- malignant tumours
- benign tumours
- non-neoplastic epithelial lesions
- benign soft tissue lesions
- haematolymphoid tumours
What is mucoepidermoid carcinoma?
- the most common of the 22 primary epithelial salivary gland malignant tumours in the WHO classification
- it is locally invasive, it can recur and can metastasise
- up to 80% have MAML2 gene fusions
What and who does mucoepidermoid carcinoma affect?
- more frequently affects the parotids but can occur in others including minor glands
- can be seen in children and young adults
- F>M
What is the most common type of ALL salivary gland tumours?
pleomorphic adenoma
What percentage of all parotid tumours does pleomorphic adenoma account for?
approx. 60%
When is the peak incidence of pleomorphic adenoma?
5th and 6th decades, but can occur at any age
How does pleomorphic adenoma present?
- benign, painless, slow growing, ‘rubbery’ lump
- usually solitary although recurrences may be multifocal
- most are associated with gene rearrangements in PLAG1 or HMGA2
