Salivary glands
What is the makeup
of the major salivary glands
• parotid (largest) – serous
acinar cells
• submandibular gland – both
mucous and serous secretory cells
• sublingual gland –
predominantly mucous glands
• 1000 minor salivary glands
– predominantly mucous
What is the drainage
of the salivary glands
• parotid gland – Stensen’ s
duct (opposite upper 2nd molar)
• submandibular gland –
Wharton’s duct
• sublingual gland – 10 small
ducts exit directly into oral cavity
How much does each
salivary gland contribute to total saliva
• parotid – largest gland,
only 25% of total volume of
saliva
• submandibular gland –
second largest, 70% of total
volume of saliva
What are the causes
of sialadenitis
• acute bacterial
• acute viral
• mumps parotitis
• HIV
• granulomatous disease
• TB
• atypical
mycobacteria
• actinomyces
• catch-scratch
disease (suppurative granuloma)
• toxoplasmosis
• tularaemia
• Sjogren’s
syndrome
• sialadenosis
• sarcoidosis
(non-caseating granulomas)
What is the
pathophysiology of bacterial sialadenitis
• stasis
• dehydration with salivary
stasis
• obstructing sialolithiasis
• bacteriology
• Staph
aureus
• Streptococcus
• Haemophilus
• anaerobes
What are the
clinical features of bacterial sialadenitis
• pain, swelling, tenderness
• induration, erythema
• fever
• leukocytosis
• purulent duct discharge
• ± stone
What is the
management of bacterial sialadenitis
• antibiotics
• rehydration
• sialagogues
(medication that promote
secreting saliva)
Pilocarpine
Bethanechol
Cevimeline
• oral hygiene, warm
compress
• bimanual massage to milk the gland
• express stone (± incise
duct opening over lacrimal
probe)
• CT re. ? abscess if fails
to respond
• surgical drainage if
abscess present
What are the
clinical features of chronic sialadenitis
• repeated episodes of salivary
gland pain and inflammation, ± overt acute bacterial
infection
What is the
pathophysiology of chronic sialadenitis
• obstruction of salivary
flow
• duct stricture
• mucous plugging
• calculi
What is the
treatment of chronic sialadenitis
• surgical removal of
offending gland
What are the
clinical features of mumps parotitis
• the most common cause of
viral acute sialadenitis
• occurs predominantly in
children
• bilateral parotid
gland swelling and pain
• low grade fever
• arthralgia, malaise,
headache
• treatment by supportive
measures
What is the effect
of HIV infection on salivary glands
• cystic
enlargement of the major salivary glands
• gradual
painless enlargement of
one or more glands
• benign cyst on USS/CT
• HIV-associated lymphoma
What are the
clinical features of TB sialadenitis
• may be 1° or 2°
• may be diffusely involved or
may be slow growing mass
• often diagnosed after
parotidectomy
What are the
clinical features of atypical mycobacterial sialadenitis
• usually children 1-3 years
• present with a mass, rapidly increases
• often erodes through skin
and drains spontaneously
• treatment by excision
What are the
clinical features of actinomyces sialadenitis
• oropharynx commensal
• associated with
• poor
oral hygiene
• recent
oral trauma
• immunosuppressed
state
• painless
induration and enlargement without
constitutional symptoms
• may erode through skin
• diagnosis by FNA or swab –
sulfur granules and
filamentous Gram-negative rods
• treatment with penicillin
• surgery reserved for
diagnosis
What are the
clinical features of cat scratch disease of the salivary
glands
• granulomatous
lymphadenitis resulting from inoculation
via skin trauma from a
domestic cat
• sterile abscess
• FNA or biopsy may aid
diagnosis
• supportive treatment
What is tularaemia
• caused by Francisella
tularensis, gram-negative
• transmitted by insect
vectors and other routes
• facial insect bite → local
erythematous papule → local lymphadenopathy →
constitutional
symptoms
• aggressive early drainage
of involved nodes may result
in systemic dissemination
of disease
• antibiotic treatment
What is Sjogren’s
syndrome
• a connective tissue
disease thought to be of
autoimmune origin
• hallmarks are
• recurrent
parotid swelling
• keratoconjunctivitis
sicca
• xerostomia
• diagnosis
by clinical and serology
• minor salivary gland
excisional biopsy → characteristic
lymphocytic infiltration
of gland
What is
myoepithelial sialadenitis (MESA)
• middle aged females
• diffuse lymphocytic
infiltration with lymphoepithelial lesions
• destruction of acini
• usually bilateral
• may predispose to lymphoma
development
What is sialadenosis
• describes recurrent bilateral
non-tender parotid swelling
• usually associated with an
underlying disease state,
nutritional
deficiency or drug
side-effect
• may be associated with
• cirrhosis
• diabetes
• alcoholism
• malnutrition
• bulimia
• ovarian insufficiency
• hypothyroidism
• pancreatic insufficiency
• side effect of multiple
drugs
What is the
management of salivary trauma
• exploration and repair of
associated facial nerve injury
(1° anastomosis or graft)
• Stensen’ s duct repaired
over Silastic stent
What is a ranula
• a cyst of the sublingual
gland
• translucent cystic mass in
the floor of the mouth
What is a plunging
ranula
• a ranula that extends
inferiorly and presents as a
neck mass
What is the
distribution of salivary gland tumours
• parotid – 80%
• submandibular – 15%
• remaining in sublingual
and minor salivary glands
What is the
malignancy rate of salivary tumours
• parotid – 80% are benign
• submandibular - <50%
benign
• sublingual and minor -
<40% benign
What is the
pathology of salivary gland tumours
• benign neoplasms
• pleomorphic
adenomas
• Warthin’s
tumour
• oncocytomas
• monomorphic
adenomas
• malignant neoplasms
• mucoepidermoid
carcinoma
• adenoid
cystic carcinoma
• acinar
cell carcinoma
• adenocarcinoma
• polymorphous
low-grade adenocarcinoma
• carcinoma
ex-pleomorphic adenoma
• squamous
cell carcinoma
• undifferentiated
carcinoma
• sarcoma
• primary lymphoma
What is the
incidence of parotid tumours in Australia
• pleomorphic adenoma 46%
• Warthin's tumour 14%
• SCC 12%
• mucoepidermoid carcinoma
4%
• adenocarcinoma 3%
• melanoma 1.7%
• lymphoma 1.7%
• adenoid cystic carcinoma
1%
What is the role of
FNA in parotid masses
• specific but poor
sensitivity (57%) for malignancy
• rarely changes management
decisions (as the position
of the tumour rather than
histology
usually determines type of resection)
What is the
bicellular theory of salivary gland tumour development
• Tumours
arise from stem cells associated
with either the excretory ducts or intercalated ducts
• The excretory
duct reserve cells give rise
to SCC and mucoepidermoid cancers
• Intercalated
duct reserve cells give rise to: pleomorphic adenoma,
oncytoma, adenoid cystic,
acinic and adenocarinomas.
What
role does
Immunohistochemistry play in differentiating malignancy from
benign tumours and
in determining type of cancer
•
Acinic cell carcinoma
express MUC3
•
Mucoepidermoid cancers
express MUC5AC; MUC1
expression is associated with worse prognosis; MUC4 expression
is associated
with better prognosis.
•
When tumour
myoepithelial cells loose p63
immunostaining it suggests that it is a carcinoma
ex-pleomorphic adenoma
•
High Ki-63 expression is
correlated with poor
survival.
What are the
features of pleomorphic adenoma
• 65% of all salivary gland
neoplasms
• most frequently found in parotid
• Annual
incidence: 2 in 100,000
• risk factors:
increasing with radiation
exposure 15-20x
• males more common (2:1) , 4th and 5th
decades
• painless mass with slow
growth
• macroscopic fibrous capsule surrounding the
tumour
• three components:
Epithelial component
Mesenchymal
(stromal)
components: Chondroid stroma (specific for
pleomorphic adenoma)
Ducts component: lined by inner cuboidal epithelial
cells and
outer myoepithelial cell
• microscopic incomplete capsule
with pseudopods, satellite nodules common:
give the recurrence
• malignant transformation 5%
• FNA for preop diagnosis : may not
differentiate bw other carcinoma
What is the
treatment of a pleomorphic adenoma
• resection by parotidectomy
with adequate margin
What are the
features of Warthin’s tumour (papillary cystadenoma)
• second most common benign
tumour of parotid gland
• 6-10% of all
parotid tumours
• older men (60-70yo)
• ↑ in
smokers 8x
• often cystic
• 10% bilateral
• can be multicentric
• brown and cystic on gross
appearance
• cystic spaces lined by two uniform rows
of cells (oncocytic epithelium)
•
lymphoid stroma as the germinal centre (lymphocytic
infiltration)
• rarely undergo malignant
transformation
• FNA for preop diagnosis
• treatment by parotidectomy
What are the
features of salivary oncocytomas
• occur almost exclusively
in parotid gland
• <1% of all salivary
neoplasms
• 6th decade
• benign
• solid
tumour
• usually encapsulated
• the epithelial
cells lined by sheets of large
polygonal cells with eosinophilic granular cytoplasm (oncocytes)
• removed by parotidectomy
What are the
features of salivary monomorphic adenomas
• rare
• include
• basal
cell adenoma
• clear
cell adenoma
• glycogen-rich
adenoma
• benign, non-aggressive
• treated by parotidectomy
What are the
features of mucoepidermoid carcinoma
of the
salivary
glands
• 3rd to 6th decade
• females more common
• 6-9% of all salivary
neoplasms
• most common malignant
tumour of parotid gland
• second most common
malignant tumour of submandibular gland (after adenoid
cystic)
• most occur in parotid
• tan-yellow colour, cystic
• mucoid, epidermoid and
intermediate cells of varying
proportions
• classified as
low, intermediate and high grade
• low grade types – behave
like benign neoplasms but may invade locally and
metastasize
• high grade types –
aggressive, high rate of metastasis, resemble SCC
histologically
(may require mucin stain to differentiate)
What are the features
of adenoid cystic carcinoma of
the salivary
glands
• 6% of all salivary
neoplasms
• most common malignancy of
submandibular and minor glands
• 4th to 6th decade
• females more common
• perineural invasion is
typical
• treatment – resection with
adjuvant radiotherapy
• good 5 year survival but
poor 10-20 year survival
What are the
features of acinic cell carcinoma of the salivary glands
• 1% of all salivary
neoplasms
• almost all in parotid
gland
• females in 5th decade
• bilateral in 3%
• benign early course but 20
year survival 50%
What are the
features of adenocarcinoma of the salivary glands
• most common in minor
salivary glands, followed by parotid
• 15% of malignant parotid
neoplasms
• aggressive tumours, likely
to recur and metastasize
What are the
features of polymorphous low-grade adenocarcinoma
of the salivary
glands
• second most common
malignancy of minor salivary glands (after adenoid cystic)
• characterized by perineural
spread
• complete resection has
favourable prognosis
What are the features
of carcinoma ex-pleomorphic adenoma
• malignant tumour that has
arisen from a pleomorphic adenoma
• 2-5% of all salivary
tumours
• presents as a sudden
increase in size of a slow growing mass that has been present
for
10-15 years
• metastases common
• very poor prognosis
• surgery followed by
radiotherapy
What are the
features of SCC of the salivary glands
• rare, <2% of salivary
tumours
• most common in
submandibular gland
• requires exclusion
of
• high-grade mucoepidermoid
carcinoma
• contiguous spread from an
adjacent SCC
• metastasis
from a cutaneous primary
• males in 7th decade
• high rate of metastasis
• surgery followed by
radiotherapy
What are the
features of undifferentiated carcinoma of the salivary
glands
• 3% of all salivary tumours
• occurs late in life
• extremely aggressive with
low survival rates
What are the
features of sarcoma of the salivary glands
• rare
• requires exclusion of
metastatic spread or direct invasion
What are the
features of primary salivary gland lymphoma
• rare
• requires proof of
no
known extra-salivary lymphoma
lymphoma arose from
salivary gland parenchyma
• prognosis good
• surgery reserved for
diagnosis
What is the approach
to salivary gland tumours
• a mass in region of
parotid considered a neoplasm until proved otherwise
• incisional or excisional
biopsy or tumour enucleation are to be avoided
• exclude other head and
neck primaries
• ? role FNA
• parotidectomy with
preservation of facial nerve
• superficial
parotidectomy for most benign and low-grade malignant
neoplasms
• total
parotidectomy for high-grade malignancies
• facial nerve preserved
unless grossly invaded with tumour
• immediate nerve graft
reconstruction if facial nerve is resected
• neck dissection for
clinically positive nodes only (no
proven benefit for elective
dissection
of a clinically negative neck)
What is the role of FNA in the diagnosis of parotid gland
enlargement
•
Sensitivity
>90% and specificity >95%.
•
Positive
predictive value of 85% and negative predictive value of 77%
•
Useful means of
differentiating benign and malignant lesions
If pre-operative
investigations have not been able to differentiate benign and
malignant disease
would you resect the facial nerve on the basis of frozen
section
• If the
lesion was not diagnosed as malignant
on pre-operative FNA then usually a superficial
parotidecomy
is performed and the final
pathology awaited.
• Frozen
section has a high false negative and positive rate and so if malignancy is
diagnosed on final
pathology and margins are positive a second operative, if
necessary resecting
the facial nerve can be performed.
What is the role of
facial nerve monitoring
•
Used when the surgeon is
inexperienced or in
difficult cases – large tumour distorting anatomy or in
re-operative
procedures.
What are the
complications of parotidectomy
Immediate
• facial
nerve injury – 10% transient, 1% permanent
• Bleeding
– requiring re-operation or haematoma
• Skin
flap necrosis
Early
•
Infection in skin
•
Salivary fistula
Late
• Numbess
in auriculotemporal nerve – numbess of ear
• Frey’s
syndrome:
u Sweating and redness in
the cheek skin during
eating or thinking food producing strong salivation
u 10-50%:
re-innervation of divided sympathetic nerves to skin by divided
post-ganglionic
secretormotor fibers to parotid from auriculotemporal nerve.
u Division
of tampanic branch of IX on the promontory of middle ear
produces relief in 50%
of cases.
What is the Minor
starch-iodine test
• affected skin area covered
with iodine solution and
allowed to dry
• area dusted with rice
starch powder
• patient given a lemon
sweet
• absorption of wet iodine
by the starch gives it a deep
blue-purple colour
• the area affected can be
measured (and guide botulinum
A therapy)
What are the
treatment options for Frey’s syndrome
• botulinum A toxin
• (enters cytoplasm or
peripheral nerve cells by
receptor-mediated endocytosis, on
the cytoplasmic
side of the cell membrane it breaks down the SNAP-25 protein
which is
essential for the exocytosis of acetylcholine vesicles)
• Division of tampanic
branch of IX on the promontory of middle ear produces relief
in 50% of cases.
What is the role of
chemotherapy and radiotherapy in salivary gland
tumours
• adjuvant radiotherapy has
improved local control and survival in patients at high
risk
of recurrence
• adjuvant chemotherapy
of little benefit
reserved
for palliation of unresectable, previously
irradiated
tumours
What
techniques have been used to identify the facial nerve at
parotidectomy
• posterior
belly of digastric - nerve runs on
its belly near the muscle origin
• transverse
process axis - nerve crosses
superior and anterior to tip of transverse
process of C2
• styloid
process - styloid
process lies deep to, above and in front of the main trunk
• tragal
pointer - its
triangular process points to the nerve, which is 5-6mm inferior
and medial
• posterior
facial vein - vein is
traced upwards to the lower nerve division, which
is then
followed to the main nerve trunk
• sulcus
between bony ridge at
antero-inferior margin of external meatus and
anterior
margin of
mastoid - nerve is
found in this V-shaped sulcus, 2-3mm
deep
• digastric
groove - nail of
finger placed with its volar surface on this will be in
contact with
the nerve
• mastoid
origin of
sternomastoid - two-finger technique, nerve is 1.5cm deep
to
the index
finger tip placed on lateral surface of mastoid perpendicular to
the other
index finger
placed on the sternomastoid, along its fibres and flush with the
lower
border of
mastoid process
• ledge
on inferior wall of
beginning of bony ear canal - nerve is 4-5mm deep to
this
• angle
between tympanic plate
and digastric - nerve bisects angle
• mastoid
process - nerve
penetrates gland medial to and anterior to mid-point of
mastoid process
• parastyloid
compartment - nerve
traverses this space
• 3D
position – 26.3mm deep
to skin, 18.8mm caudal to the summit of the
antitragus
• tympano-mastoid
fissure - nerve exits
from stylo-mastoid foramen 6-8mm medial
to its inferior
end
• tympano-mastoid
notch - the
stylo-mastoid foramen is 1cm medial to the notch
• drop
off point of
tympano-mastoid fissure - the stylo-mastoid
foramen is
approx 7.2mm
and nerve 3-6mm deep to this point
The main trunk
of the facial nerve is 8mm
deep to the tympano-mastoid suture line at the level of the
digastric muscle.
What is the Superficial
musculoaponeurotic
system
• The SMAS is a superficial
fascial layer that extends throughout the
cervical facial region. In the
lower face, the SMAS
invests the facial muscles and is continuous with the platysma
muscle. Superiorly,
the SMAS ends at the level of the
zygoma because
of attachments of the fascial layers to the zygomatic arch.
• In the lower face, the
facial nerve always runs deep to the platysma and SMAS and innervates the muscles on their undersurfaces (except for the buccinator,
levator anguli
oris, and mentalis muscles).
• The SMAS also
helps the surgeon identify the location of the facial nerve
during dissection
toward the midline of the face, where the nerve
can be found running on top of the masseter muscle just
below the SMAS.
What is the
distribution of salivary calculi
• most common in
submandibular duct
• opening
is above gland, encouraging
stasis
• submandibular saliva
contains more
mucus and calcium and is more
alkaline
• usually young to middle
age patients
How should a
salivary calculus be investigated
• history –
• intermittent painful
swelling after eating (induced by
lemon juice)
• examination –
• obstructed duct
demonstrated by lemon juice on tongue
not producing salivary flow
from that
duct
• stone may be visible or
palpable
• plain radiograph
• (submandibular 80%
radio-opaque, parotid
70% radio-opaque)
• USS
• (demonstrates stones to
0.5mm, gland fibrosis, confirm
not lymph node)
• Sialography
• (stones, duct shape and
stenoses)
• (cannulation difficulties,
can be painful)
• MRI
• CT scan
• endoscopy
What are the
treatment options for salivary calculi
• conventional surgery
• salivary
papillotomy
• gland
resection
• endoscopy
• forceps
• suction
• basket snare
• laser
lithotripsy
• shockwave
lithotripsy
• extracorporal lithotripsy
with endoscopy
• extracorporeal lithotripsy
without endoscopy