Salivary Gland Pathology

Question 1

What is a mucocele?

Answer 1

Mucous extravasation cyst or phenomenon
- Consists of cavity, wall, lining
- Mucocele is lined with macrophages instead of epithelium

Question 2

How does a mucocele present?

Answer 2

Fluid filled

Erythematous periphery with translucent/blue centre

Burst and comes back in same place

Lower lip

Younger patients

Question 3

What questions should we ask patients about any lump?

Answer 3

• How long has it been there?
• Has it changed in size?
• Pain?

Question 4

How do blisters in pemphigoid/gus differ from mucocele?

Answer 4

Blisters tend to occur in different places
 Recurs but not in exact same place

Question 5

What is a ranula and its features?

Answer 5

Like a mucocele in floor of the mouth which is larger
- Very translucent
- Resembles belly of frog
- Plunging ranula- can affect swallowing and breathing

Question 6

How may a ranula be treated?

Answer 6

Marsupialisation

Question 7

What causes mucoceles?

Answer 7

Trauma to duct of salivary gland resulting in severance and leaking and collects in connective tissue (bite, fight, bike accident)
-> Location of saliva is abnormal- body forms wall of granulation tissue around it to contain it

Question 8

How is a mucocele treated?

Answer 8

• Surgical removal of gland and injured duct
• May heal itself

Question 9

What is a mucous retention cyst?

Answer 9

As a result of dilation of ducts of glands, saliva collects within

** Something expanding may be putting pressure on duct causing this collection

Question 10

What are the clinical features of a mucous retention cyst?

Answer 10

 Upper lip usually
 Older people
 Has epithelial lining
 Can occur within maxillary sinus (may be discovered incidentally on CBCT)

Question 11

What are the histopathological features of a mucocele?

Answer 11

• Cavity- filled with saliva, may have some neutrophils
• Wall- granulation tissue
• Lining- made of macrophages (foam cells)
• On outer surface- epithelium

Question 12

What are the histological features of granulation tissue? (first stage in healing process)

Answer 12

• Macrophages- remove debris, phagocytosis of necrotic tissue or pathogens, they will try to engulf saliva as well (become big and pale- collections of foam cells)
• Plasma cells
• BVs- many capillaries
• Lymphocytes
• Fibroblasts- form collagen (appears pink/brown)

Question 13

What happens to granulation tissue over time?

Answer 13

Becomes more fibrous and less cellular
-> BVs also reduce

Question 14

What else can cause macrophages to become foam cells?

Answer 14

If they engulf lipid, mucous/mucin

Question 15

Where doe sialoliths tend to block minor salivary glands?

Answer 15

Buccal mucosa

Question 16

Why is submandibular gland most likely to get blocked?

Answer 16

• Duct is long and goes in upward direction
• Produces mixed secretion (can thicken if dehydrated or due to medication)
• The duct is also curved- promotes stagnation of saliva

Question 17

What type of sialoliths can occur?

Answer 17

Mucous plug- not seen on plain radiographs

Calcified- seen on plain radiographs (lower occlusal used)

-> both may be palpable

Question 18

How are sialoliths treated?

Answer 18

• Surgery to remove stone (and perhaps part of the gland)
• Retrieval of stone

Question 19

What are the histopathological features of sialoliths?

Answer 19

• Dilated duct
• Calcification
• Lining of duct- becomes stratified squamous epithelium with thin layer of keratin on surface (changes from columnar), due to trauma and friction from jagged edges of sialolith (metaplasia)
• Inflammatory cells within gland- saliva being secreted collects and is moved very slowly within gland causing chronic sialadenitis
• Dark acini- serous
• Pale acini- mucous

Question 20

What is the likely cause of a slow growing lump present in palate with pink appearance with presence of red capillaries and rubbery texture?

Answer 20

 Pleomorphic adenoma- commonest type of salivary gland tumour (can occur anywhere- lip, tongue, lacrimal glands, mucosa but classically seen in palate)

Question 21

What are the layers to consider when evaluating swelling in the palate?

Answer 21

Epithelium (if it looks uniform it is unlikely to be coming from here)

Lamina propria connective tissue (BVs, fibrous tissue, minor salivary glands, nerves)

Bone

Consider if it is close to teeth- abscess (check if TTP, radiograph, sensibility test, fluctuant texture)

Question 22

What is meant by pleomorphic in terms of cancer?

Answer 22

cells change in size, shape and appearance

Question 23

What is meant by pleomorphic in terms of adenoma?

Answer 23

variety of tissue appearances (no 2 are the same under microscope)

Question 24

How is a Pleomorphic Adenoma treated?

Answer 24

Excisional biopsy
 If larger- may be an incisional biopsy (then removed)

Question 25

What are the histopathological features of Pleomorphic Adenomas?

Answer 25

Myopepithelial cells in sheets or duct shapes- source Fibrous tissue- dense/hyalinised -> lack of nuclei and fibrous cells Myxomatous tissue- soft and jelly like -> difficult to remove surgically Fat tissue Appears appearing like bone and cartilage Incomplete capsule- tumour can grow through gaps

Question 26

What is the main complication for pleomorphic adenoma?

Answer 26

If it remains for long periods of time- it can undergo malignant transfer (5%)  Carcinoma ex-pleomorphic adenoma

Question 27

How long is the follow up after a PA removal?

Answer 27

5 year follow up for Pleomorphic Adenoma  Recurrence is more likely in tumours that arise from minor glands

Question 28

What is the most common salivary gland site for Pleomorphic Adenoma?

Answer 28

Parotid

Question 29

What are the tissue layers to consider when we see swelling in the face?

Answer 29

- Skin (epidermis) - Epithelium - Dermis (fibrous connective tissue)- muscle, nerve endings, blood vessels, fibroblasts, collagen, lymphatics, sweat glands, hair, sebaceous glands, nails in some regions - Bone (osteoma) - Muscle (myoma) - Fat (lipoma)

Question 30

What is the likely cause of an asymptomatic slo growing swelling below the ear which has been present for many years?

Answer 30

Warthin's tumour

Question 31

What is another swelling covered in normal skin that can be seen in head and neck?

Answer 31

Epidermal cyst (sebaceous cysts are also possible) - Usually on scalp or back of neck

Question 32

What are the clinical features of Warthin's tumour?

Answer 32

- Slow growing - Occurs exclusively within parotid gland - Associated with smoking - Can be bilateral - Can be multifocal- more than one tumour within one gland (entirely separate)

Question 33

How does warthin's tumour originate?

Answer 33

Originates from entrapment of lymphoid tissue within salivary gland tissue (or VV) during foetal development

Question 34

How does Warthin's tumour appear histologically?

Answer 34

- Round - Well defined fibrous capsule (all contained within this) - Dark staining- lymphoid tissue (contains germinal centres- formation of lymphocytes occurs here) - Pink cells- lining of cystic spaces (contains protein) - Columnar epithelium - Plaque cells replace salivary gland acini in major glandular tissue around warthins tumour (dry mouth) - Congestion and inflammation within the gland can occur around tumour (pressure leading to stagnation of saliva resulting in sialadenitis)

Question 35

How is Warthin's tumour treated?

Answer 35

Surgical removal- easy due to capsule -> Malignant potential and recurrence is very rare

Question 36

What are the histological features of Adenoid Cystic Carcinoma?

Answer 36

- Made up of small cuboidal cells with dark nuclei (cells are not pleomorphic- they are regular in shape and size) - May have tubular, sheet, Swiss cheese appearance (cribriform) - Spaces in cribriform regions- not cysts but contain ground substance of connective tissue within them (good prognostic indicator) - Perineural invasion is common- malignant cells grow along the myelin sheath (whirlpool appearance), can be multiple instances of this within one malignant lesion

Question 37

How do carcinomas usually metastasise?

Answer 37

LN then blood

Question 38

How does adenoid cystic carcinoma spread?

Answer 38

Goes straight to blood then other areas of body, commonly the lungs -> Metastases to LN comes as third stage