salivary neoplasms Flashcards
what is the mechanism of oncogenesis for most salivary neoplasms?
chromosomal translocations
how can chromosomal translocations be visualised?
fluorescence in situ hybridisation (fluorescent probes will be separated)
describe the site prevalence of salivary neoplasms (3)
- most in parotid, least in sublingual
- parotid most likely to be benign
- sublingual most likely to be malignant
where are most benign salivary neoplasms found?
parotid gland
which salivary gland has the highest proportion of malignant salivary neoplasms?
sublingual
give some features of benign salivary gland neoplasms (4)
- well-differentiated, encapsulated
- slow-growing, presenting late
- non-invasive, non-metastatic
- symptoms usually cosmetic or pressure-induced
what are the two most common salivary neoplasms?
pleomorphic adenoma
Warthin tumour
list benign salivary gland neoplasms (10)
- pleomorphic adenoma
- Warthin tumour
- myoepithelioma
- oncocytoma
- basal cell adenoma
- lymphadenoma
- cystadenoma
- sebaceous adenoma
- canalicular adenoma
- ductal papilloma
describe pleomorphic adenoma
(what, clinical, age)
- commonest salivary neoplasm
- benign but may undergo malignant transformation over time
- 30-60yo
- painless, slow-growing, discrete, mobile rubbery mass; nodular
- > 75% in parotid, less in submandibular or minor glands
- may have pseudopodia (extensions)
pleomorphic adenoma histology (3)
- haphazard arrangement of pleomorphic epithelial cells centred around ductal structures
- bilaminar ducts containing mucin
- myxochondroid stroma +/- cartilage-like material or bone
pleomorphic adenoma age group
30-60yo
pleomorphic adenoma management (2)
- excision with wide margin
(radiotherapy resistant) - monitor for malignant change
pleomorphic adenoma commonest site
superficial lobe of parotid
why are the pseudopodia of a pleomorphic adenoma important?
enucleation may leave parts of tumour in situ –> recurrence
why may some pleomorphic adenomas be difficult to remove?
- may be mostly formed of myxochondroid stroma = jelly-like, fragile
- prone to rupture and seeding of multiple foci
describe Warthin tumour (demographic, clinical)
- > 60yo males with smoking history
- mainly in parotid (lower pole)
- benign, mobile, firm/fluctuant, well-defined mass
- may be single/multiple, bi/unilateral
Warthin tumour demographic
> 60yo males with smoking history
Warthin tumour commonest site
lower pole of parotid
Warthin tumour histology (3)
- papillary structures growing into cystic spaces
- lymphocyte-dense stroma - similar to lymph node with lymphoid follicles
- pseudostratified columnar epithelium, usually bilaminar- densely eosinophilic cytoplasm
Warthin tumour treatment
excision (low recurrence rate
list the 5 main malignant salivary neoplasms
- mucoepidermoid carcinoma
- adenoid cystic carcinoma
- acinic cell carcinoma
- carcinoma ex-pleomorphic adenoma
- polymorphous adenocarcinoma
prognostic factors of malignant salivary neoplasms (5)
- stage at presentation (most important)
- grade
- CN involvement (affects management)
- perineural invasion (poor)
- site (parotid»)
describe mucoepidermoid carcinoma (age, site, clinical, histology)
- wide age range
- minor glands of palate or parotid, often a firm painless swelling
histology: - grade varies - mucous, epidermoid and intermediate cells differentiate grades
– more mucous = lower
– more epidermoid = higher - majority have prominent cystic component (= lower grade)
which is the most common malignant salivary neoplasm?
mucoepidermoid carcinoma
mucoepidermoid carcinoma common sites (2)
minor glands of palate
parotid
mucoepidermoid carcinoma treatment (2)
low grade (cystic mucus-filled) = excision with margin
high grade (solid epidermoid) = surgery +/- radiotherapy
describe adenoid cystic carcinoma (site, symptoms, histology)
- any gland
- slow-growing, highly infiltrative
- late diagnosis = pain, altered sensation, nerve palsy
histology: - uniform hyperchromatic cells, sometimes true ducts, angulate peripheral layer
- pseudocysts in cribriform/swiss-cheese pattern (degeneration of intercellular spaces)
- areas with tubular patterns
adenoid cystic carcinoma histology (3)
- uniform hyperchromatic cells, sometimes true ducts, angulate peripheral layer
- pseudocysts in cribriform/swiss-cheese pattern (degeneration of intercellular spaces)
- areas with tubular patterns
adenoid cystic carcinoma treatment
surgery but difficult to fully excise (infiltrative)
describe acinic cell carcinoma (grade, age, site, histology)
- most are low to intermediate grade but still invasive
- young and middle aged pts
- parotid gland = serous acinar origin, serous granules, PAS stain
- multiple histological subtypes
- commonly recurs
acinic cell carcinoma common site
parotid (serous acinar origin)
describe carcinoma ex-pleomorphic adenoma (what, types, histology)
- develops from pre-existing pleomorphic adenoma = slow growth then suddenly enlarging/developing malignant symptoms
- intracapsular type (behaves like pleomorphic adenoma)
- minimally invasive type (4-6mm invasion)
- invasive type (>4-6mm, worse prognosis)
- histological evidence of pleomorphic adenoma but may be obliterated by scar tissue, wide variation
describe polymorphous adenocarcinoma (site, prognosis, histology)
- minor glands, esp on palate
- overall good prognosis but local recurrence
- various histological patterns
polymorphous adenocarcinoma site
minor glands, esp on palate
give two conditions that may mimic salivary neoplasm
- necrotising sialometaplasia (benign, inflammatory)
- IgG4 sclerosing disease
surgical complications of parotid gland tumour surgery (8)
- Frey’s syndrome
- greater auricular nerve damage (ear lobe paraesthesia)
- temporal nerve weakness
- permanent facial nerve weakness, facial asymmetry
- haematoma
- necrosis near incision
- salivary fistula or sialocele
- recurrence
what is Frey’s syndrome?
uncharacteristic sweating near parotid glands in response to food stimulus
what are the three different types of parotid gland surgical intervention
- extracapsular dissection
- superficial parotidectomy (superficial to facial nerve)
- total parotidectomy
pros and cons of extracapsular dissection of parotid tumours
+:
- decreased risk of Frey’s syndrome, nerve damage, facial deformity
- decreased operating time and smaller flap size
-:
- careful case selection
- specific training and experience, less room for error
