Salivary Gland Disorders Flashcards
What are the salivary glands?
Parotid
Submandibular
Sublingual
Minor salivary glands
What is the parotid gland
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
What is the submand gland
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
What is the sublingual gland
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
What are the minor salivary glands
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
Diagnostic imaging of salivary glands
Plain films
Sialography
CT scans
MRI
Salivary gland infection (sialadenitis) causes
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
What is viral parotitis
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
Acute bacterial sialadenitis
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
Types of obstructive salivary gland diseases
Sialolithiasis
Mucocele
Ranula
What is sialolithiasis
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
What is a mucocele
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
What is a ranula
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
What is neoplasm of the salivary glands
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
Examples of benign salivary gland tumours
Pleomorphic adenoma
Warthin tumour (papillary cystadenoma lymphomatosum)
Basal cell adenoma
Examples of malignant salivary gland tumours
Mucoepidermoid carcinoma
Adenoid cystic carcinoma
Polymorphous low grade adenocarcinoma
What is pleomorphic adenoma
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
Histology of pleomorphic adenoma
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
Tx of pleomorphic adenoma
Complete surgical excision of affected salivary gland
Avoid enucleation and tumour spill
What is warthin tumour
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
What is mucoepidermoid carcinoma
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
Histology of mucoepidermoid carcinoma
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
Tx of mucoepidermoid carcinoma
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
What is adenoid cystic carcinoma
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
Histology of ACC
Cribriform pattern
Infiltrative proliferation of basaloid cells
Perineural invasion
Tx of ACC
Complete local excision
Tendency for perineural invasion, may have to sacrifice facial nerve
Postop radiotherapy
Prognosis of ACC
42% local recurrence rate
Distant metastasis to lung
5y survival 75%, 20y survival 13%
