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

 

File:Warthin tumor (2).jpg

 

 

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