2. Objectives
n
n
n
n
n
n
By the end of 2 session the
student will be able to:
Know the applied anatomy of
the SG
Autonomic innervations of
the SG and its effect function
Inflammatory disorder of the
SG
Obstructive disorders
SG neoplasm's . Clinical
presentation, investigations.
n
n
n
n
n
Epithelial tumors adenomas
Carcinomas , adenoid cystic
carcinoma ,
adenocarcinoma
Non epithelial tumors ,
hemangioma and
lymphangioma
Potential complications
during surgery or trauma
Gustatory sweating
4. Parotid gland
Largest salivary gland
n
It is located in a compartment anterior to the ear and is
invested by fascia that suspends the gland from the
zygomatic arch. The parotid compartment contains the
parotid gland, nerves, blood vessels, and lymphatic
vessels, along with the gland itself
Facial nerve bisects gland
§ Superficial lobe , Deep lobe
§ Superior to mandible anterior to angle of jaw and
auricle
§ Between SCM muscle and mandibular ramus
5. Parotid gland
n
n
n
n
n
Relations
Above: external auditory
meats and TMJ
Below: post belly digastric
Anteriorly: mandible and
masseter ms.
Medially: styloid process and
its muscles separate the
gland from the internal
jugular vein, internal carotid
artery ,the last four cranial
nerves, lateral wall of the
pharynx
7. Anatomy: Parotid Duct
n
n
It is located approximately 1
cm below the zygoma and
runs horizontally.
It passes anteriorly and lie
superficial to the masseter
muscle and then penetrates
the buccinator muscle to open
intraorally
n It is 3 mm in diameter
n 6cm in length
8.
9. Submandibular Gland
n
n
Large superficial lobe and
a small deep lobe, that
connect around the
mylohyoid ms.
Superficial lobe lies at the
angle of the jaw, wedged
bet the mandible and
mylohyoid and
overlapping the digastric
ms.
10. Submandibular gland
relations
n
Superficially:
n
The skin, the platysma, the
capsule (deep fascia), the cervical
branch of
Facial Nerve, and the Facial Vein
Deeply:
the deep aspect lies against the
mylohyoid for the most part. But
posteriorly lies on the hyoglossus
and comes in contact with the
lingual and hypoglossal nerves.
n
n
Both nerves lie on the hyoglossus as
they pass forward to the tongue
11. Submandibular Duct
n
n
n
n
Wharton’s duct passes forward
along the superior surface of
the mylohyoid adjacent to the
lingual nerve.
2-4mm in diameter & about
5cm in length.
It opens into the floor of the
mouth thru a punctum.
The punctum is a constricted
portion of the duct to limit
retrograde flow of bacterialaden oral fluids.
12. Sublingual glands
The ducts of the
sublingual glands are
called Bartholin’s ducts.
n In most cases,
Bartholin’s ducts
consists of 8-20 smaller
ducts of Rivinus. These
ducts are short and
small in diameter
n
13. Sublingual glands
n
The ducts either open…
n individually into the FOM near the
punctum of Wharton’s duct
n on a crest of sublingual mucosa called
the plica sublingualis
n open directly into Wharton’s duct
14. Physiology& Saliva content
n
Normal daily production is 1-1.5L
n
Water 99,5%
n
Organic compounds – mucin, amylase,
lysozym, immunoglobulin A
n
Anorganic compounds – HCO3-, I, K,
Cl, Na, Ca, phosphates and others.
15. Physiology and Function
n
n
About 45% is produced by the parotid gland,
45% by the submandibular glands, and 5% each
by the sublingual and minor salivary glands.
Saliva is produced at a low basal rate throughout
the day, with flow increasing 10-fold during
meals.
Saliva functions to maintain lubrication of the
mucous membranes and to clear food, cellular
debris, and bacteria from the oral cavity.
16. Autonomic Innervations
Parasympathetic Stimulation results in abundant,
watery saliva with a decrease in amylase in saliva
and an increase in amylase in the serum.
n Parasympathetic Interruption to salivary glands
results in atrophy, while sympathetic interruption
doesn’t cause a signifiant change.
n
17. Parasympathetic Innervation
In the case of the parotid, parasympathetic
fibers originate from CN IX
n In the case of the Submandibular and
Sublingual glands, the parasympathetic fibers
originate in CN VII
n
18. Sympathetic Innervation
n
Stimulation by the
sympathetic nervous
system results in a
scant, viscous saliva
rich in solutes with an
increase in amylase in
the saliva and no
change in amylase in
the serum.
n
n
n
n
For all of the salivary glands,
these fibers originate in the
Superior Cervical ganglion
and travel with arteries to
reach the glands:
1) External Carotid artery for
the Parotid
2) Lingual artery for the
Submandibular, and
3) Facial artery in the case of
the Sublingual.
20. 1-Ultrasonography
n
n
Non-invasive is most
useful in the evaluation of
deeply seated masses
and is often helpful in
distinguishing a solid
mass from one that is
cystic.
This technique relies on
the fact that different
tissue densities result in
different degrees of
reflection or echo
production of a beam of
high-frequency sound
waves.
21. 2-Sialography
This technique relies on retrograde
injection of a water soluble radioopaque
fluid, also known as contrast medium, into
the duct system of either the parotid or
submandibular salivary gland.
n A plain radiograph is made, and the
pattern of distribution of the contrast
medium is assessed
n
23. 3-CT SCAN
CT is a cross-sectional radiologic imaging
technique that is particularly useful in the
evaluation of bone lesions.
n Not only can the density and margins of
the lesion in question be evaluated with
this technique but cortical expansion and
fine internal details can often be more
readily appreciated compared with plain
film images. Use of contrast media has
extended the utility of this technique in
areas of soft tissue pathology.
n
24. n Needle
biopsy guided by CT scan can
be employed for difficult-to-reach tumors
such as parapharyngeal space
neoplasms.
n CT sialography, while often employed in
the past, does not offer superior imaging
to high-resolution CT scan or MRI alone
and will rarely alter management.
25. 4-MRI & CT
n
CT scan or MRI is useful
for determining the extent
of large tumors and for
evaluating extraglandular
extension. Additionally, CT
scan or MRI is helpful in
distinguishing an
intraparotid deep-lobe
tumor from a
parapharyngeal space
tumor and for evaluation of
cervical lymph nodes for
metastasis.
27. Minor salivary gland neoplasm's,
alternatively, often are more difficult to
assess on examination, and use of
preoperative CT scan or MRI is important
for determining the extent of tumor, which
otherwise is not clinically appreciable.
n This is particularly apparent for paranasal
sinus salivary gland neoplasms, where
skull base or intracranial extension may
impact resectability.
n
28. 5-Radionuclide Imaging
n
n
Radionuclide imaging relies on the specific
uptake of any one of several isotopes by various
types of tissues or cells. Localization of the
isotope is determined by examining the patient
with a gamma scintillation camera.
The most commonly used isotope, technetium
99m pretechnetate, can demonstrate areas of
high metabolic activity.
29. Radionuclide Studies
Technetium 99m pretechnetate,
is a radioisotope that decays
and emits a gamma ray. Half
life of 6 hours.
n It is useful in identifying
inflammatory conditions such
as osteomyelitis, areas of active
skeletal lesions of fibrous
dysplasia or metastatic
disease
30. 6-Fine needle aspiration biopsy
n
FNAB is performed using a
syringe with a 20-gauge and
after LA ,the needle is advanced
into the mass , the plunger is
activated to create a vacuum in
the syringe the needle is moved
back and forth throughout the
mass with pressure maintained
in the plunger , then pressure
released the needle withdrawn ,
the cellular material was
histologically examined
31. 7-SIALOCHEMISTRY
n
Principally the concentration of Na and K which
is normally change with salivary flow rate , any
changes in the concentration of electrolyte is
indicative of SG disease e.g. elevated Na
concentration with a decreased K concentration
is indicated of SG Sialadenitis
32. 8-Sialoendoscopy
n
n
The SG endoscopic
technique opens new
horizons in the field of
salivary gland diseases.
Salivary gland stones
and sialadenitis no
longer are absolute
indications for
sialoadenectomy.
40. Functional Disorders
n
Sialorrhea (Increase in saliva flow)
n Psychosis,
mental retardation, certain
neurological diseases, rabies,
n mercury poisoning
n
Xerostomia (Decrease in saliva flow)
n Mumps,
Sjogrens, syndrome, lupus, postirradiation
n Post surgical
41. Functional Disorders
n Mucocele
n Secondary
to trauma
n 70% occur in lower lip
n Excisional biopsy usually curative
n Ranula
n Sublingual salivary gland mucocele
n Treatment should include removal of sublingual
gland
42. Mucocele
n
n
Mucus is the exclusive
secretory product of the
accessory minor salivary
glands and the most
prominent product of the
sublingual gland.
The mechanism for mucus
cavity development is
extravasation or retention
n
n
Secondary to trauma
70% occur in lower lip
43. Mucocele
"
"
"
"
Extravasation is the leakage of fluid from the
ducts or acini into the surrounding tissue.
Extra: outside, vasa: vessel
Retention: narrowed ductal opening that cannot
adequately accommodate the exit of saliva
produced, leading to ductal dilation and surface
swelling, less common phenomenon.
Lacks a true epithelial lining
44. Treatment of Mucocele
Excision with strict removal of
associated minor salivary glands
n Avoid injury to other glands during
primary wound closure
n
46. Ranula
n
Is a term used for
mucoceles that occur in
the floor of the mouth.
n
The name is derived
form the word rana,
because the swelling
may resemble the
translucent underbelly
of the frog.
47. Ranula
n
n
n
Presents as a blue dome
shaped swelling in the floor of
mouth (FOM).
They tend to be larger than
mucocele & can fill the FOM
& elevate tongue.
Located lateral to the
midline, helping to
distinguish it from a midline
dermoid cyst.
48. Plunging or Cervical Ranula
Occurs when spilled mucin dissects
through the mylohyoid muscle and
produces swelling in the neck.
n Concomitant FOM swelling may or may
not be visible.
n
MRI of plunging ranula
50. Treatment of Ranula
Marsupialization ( deroofing ) has fallen
into disfavor due to the excessive
recurrence rate of 60-90%
n Sublingual gland removal via intraoral
approach
n
51. Obstructive SG Disorders
Sialolithiasis /stone
Sialolithiasis results in
a mechanical
obstuction of the
salivary duct
n Is the major cause of
unilateral diffuse
parotid or
submandibular gland
swelling
n
52. Sialolithiasis
Salivary calculi ( Stone )
The exact pathogenesis of
sialolithiasis remains unknown.
n Thought to form via….
n
an initial organic nidus that progressively
grows by deposition of layers of inorganic
and organic substances.
n
May eventually obstruct flow of saliva
from the gland to the oral cavity.
53. Etiology
Hypercalcemia…in rats only
n Xerostomic meds
n Tobacco smoking, positive correlation
n Smoking has an increased cytotoxic effect
on saliva, decreases PMN phagocytic
ability and reduces salivary proteins
n
54. Sialolithiasis
Reasons of arising
1. Anatomy 2.Components of
saliva
Upwarding route
n Mucus protein
n Longer duct
n Calcium content
n Curve duct
n
55. Reasons sialolithiasis may occur more often in
the SMG
n
n
n
n
n
Saliva more alkaline
Higher concentration of
calcium and phosphate in the
saliva
Higher mucus content
Longer curved duct
Anti-gravity flow
56. Sialolithiasis
"
"
"
Obstruction Phenomenon :Acute ductal
obstruction may occur at meal time when saliva
producing is at its maximum, the resultant
swelling is sudden and can be painful.
Gradually reduction of the swelling can result but
it recurs repeatedly when flow is stimulated.
This process may continue until complete
obstruction and/or infection occurs.
57. Sialolithiasis
n
n
The higher frequency of sialolithiasis in the
submandibular gland is associated with several
factors: the pH of saliva (alkaline in the
submandibular gland, acidic in the parotid
gland); the viscosity of saliva (more mucous in
the submandibular gland);
and the anatomy of the Wharton’s duct (the duct
of the submandibular salivary gland opening into
the mouth at the side of the lingual frenum is an
uphill course .Stones are rarely found in the
sublingual gland.
60. Stone Composition
n
Organic; often predominate
in the center
n Glycoproteins
n Mucopolysaccarides
n Bacteria!
n Cellular
n
debris
Inorganic; often in the
periphery
n Calcium
carbonates & calcium
phosphates in the form of
hydroxyapatite
61. Other characteristics:
Despite a similar chemical make-up,
80-90% of SMG calculi are radio-opaque
50-80% of parotid calculi are radiolucent
n 30% of SMG stones are multiple
60% of Parotid stones are multiple
n
62. Submandibular Gland Lithiasis
n
n
Diagnosis
Clinical examination ,
clinial feature and
radiographic examination
Pain and sudden
enlargement of
gland while eating
n Palpation of stone
submandibular duct
n Occlusal radiograph
(80%)
n
63. Diagnostics: Plain occlusal film
Effective for
intraductal stones,
while….
n intraglandular,
radiolucent or
small stones may
be missed.
n
69. Transoral vs. Extraoral Removal
Indication of Transoral Removal
(Sialolithotomy)
n if
a stone can be palpated thru the mouth, it
can be removed trans-orally (TO)
n Or if it can be visualized on a true central
occlusal radiograph, it can be removed TO.
n Finally, if it is no further than 2cm from the
punctum, it can be removed TO.
70. Posterior Stones
n
n
n
n
Deeper submandibular stones (~15-20% of
stones) may best be removed via
sialadenectomy.
Some surgeons say can still remove transorally,
but should be done via general anesthetic.
Floor of mouth (FOM) opened opposite the first
premolar, duct dissected out, lingual nerve
identified.
Duct opened & stone removed, FOM
approximated.
72. Gland excision
Sialoadenectomy
While some believe that a gland with
sialolithiasis is no longer functional, a recent
study on SMGs removed due to sialolithiasis
found there was no correlation between the
degree of gland alteration and the number of
infectious episodes.
n 50% of the glands were histopathologically
normal or close to normal
n A conservative approach to the gland/stone
seems to be justified
n
74. Sialadenitis
"
Awareness of salivary gland infections
was increased in 1881 when President
Garfield died from acute parotitis following
abdominal surgery and associated
systemic dehydration.
76. Pathogenesis
"
"
"
Causes:
1. Retrograde contamination of the
salivary ducts and parenchymal tissues by
bacteria inhabiting the oral cavity.
2. Stasis of salivary flow through the ducts
and parenchyma promotes acute
suppurative infection.
77. Acute Suppurative
More common in parotid gland.
n Suppurative parotitis, surgical parotitis,
post-operative parotitis, surgical mumps,
and pyogenic parotitis.
n The etiologic factor most associated with
this entity is the retrograde infection from
the mouth.
n 20% cases are bilateral
n
79. Risk Factors continued…
n
n
n
n
n
Neoplasms (pressure occlusion of duct)
Sialectasis (salivary duct dilation) increases the
risk for retrograde contamination. Is associated
with cystic fibrosis and pneumoparotitis
Extremes of age
Poor oral hygiene
Calculi, duct stricture
80. Complex picture
n
There must be other factors at work…..
n
Sialolithiasis can produce mechanical
n
obstruction of the duct resulting in salivary stasis
and subsequent gland infection.
Calculus formation is more likely to occur in
SMG duct (85-90% of salivary calculi are in the
SMG duct) However, the parotid gland remains
the MC site of acute suppurative infection.
81. Acute Suppurative Parotitis - History
n
n
n
n
Sudden onset of erythematous swelling of the
pre/post auricular areas extend into the angle
of the mandible.
Male above 60 affected more than female
Staphylococcus aureus is the most causative
organism hence it is colonizes around ductal
orifice
Decrease salivary flow
82. Clinical Presentation
Rapid onset of the preauricular swelling
n Erythema
n Pain
n Palpation ( milking ) of the involved gland
will reveal no flow or elicit a thick ,
purulent discharge from the orifice of the
duct
n
83. Bacteriology
n
Purulent saliva should be sent for culture.
n Staphylococcus
aureus is most common
n Streptococcus pnemoniae and S.pyogenes
n Haemophilus Influenzae also common
84. Lab Testing
n
n
n
n
n
n
Parotitis is generally a clinical diagnosis
However, in critically ill patients further
diagnostic evaluation may be required
Elevated white blood cell count
Serum amylase generally within normal
If no response to antibiotics in 48 hrs can
perform MRI, CT or ultrasound to exclude
abscess formation
Can perform needle aspiration of abscess
85. Treatment of Acute Sialadenitis
Symptomatic and supportive care
n Intravenous fluid hydration
n Warm compresses, maximize OH, give
sialogogues (lemon drops)
n External salivary gland massage if
tolerated
n
86. Treatment of Acute
Sialadenitis/Parotitis
Antibiotics!
n 70% of organisms produce B-lactamase or
penicillinase
n Need B-lactamase inhibitor like Augmentin
or Unasyn or second generation
cephalosporin
n Can also consider adding metronidazole
or clindamycin to broaden coverage
n
87. Differentiating diagnosis
n
Tumor in sublingual gland
n
Tumor in submandibular gland
n
Space infection in
submandibular region
n
Lymphadenopathy
89. Minor Salivary Glands
n From
600-1000 minor salivary glands
are located throughout the paranasal
sinuses, nasal cavity, oral mucosa,
hard and soft palate, pharynx, and
larynx. Each gland is a discrete unit
with its own duct opening into the oral
cavity.
90.
91. SALIVARY GLAND
NEOPLASMS 2
Dr. Adel I. Abdelhady
BDS, Msc, (Tanta, Egypt), PhD
(Egypt,USA)
Oral and Maxillofacial Surgery Dept.
College of Dentistry, King Faisal
University, KSA
92. Salivary Glands Neoplasms
n
n
Neoplasms arising in the salivary glands are
relatively rare, yet represent a wide variety of
benign and malignant histological subtypes
The incidence of salivary gland neoplasms as a
whole is approximately 1-2 per 100,000
individuals in the US. An estimated 750 deaths
related to salivary gland tumors occur annually.
Salivary gland neoplasms make up 1% of all
head and neck tumors
93. n
Salivary gland neoplasms present most
commonly in the sixth decade of life.
Malignant lesions typically present after
age 60, while benign lesions usually
present after age 40. Benign neoplasms
occur more frequently in women, but
malignant tumors are distributed equally
between the sexes.
94. n
n
n
Among salivary gland neoplasms, 80% arise in
the parotid glands, 10-15% arise in the
submandibular glands, and the remainder occur
in the sublingual and minor salivary glands
The most common tumor of the parotid gland
is the pleomorphic adenoma, which represents
about 60% of all parotid neoplasms .
Almost half of submandibular gland neoplasms
and the majority of sublingual and minor salivary
gland tumors are malignant.
95. n
Salivary gland neoplasms are rare in
children. Most tumors (65%) are benign,
with hemangiomas being the most
common, followed by pleomorphic
adenomas. In children, 35% of salivary
gland neoplasms are malignant.
Mucoepidermoid carcinoma is the most
common salivary gland malignancy in
children
96. History of the Mass or Swelling
Initial history should focus on
n the presentation of the mass,
n growth rate,
n changes in size or symptoms with meals,
n facial weakness or asymmetry, and
n associated pain.
n A thorough general history will give insight into
possible inflammatory, infectious, neoplastic or
autoimmune etiologies
97. History
n
A thorough history is important in managing
patients with suspected salivary gland
neoplasms. A diverse variety of pathologic
processes, including infectious, autoimmune,
and inflammatory diseases, can affect the
salivary glands and may masquerade as
neoplasms. While most masses of the parotid
gland ultimately will be diagnosed as true
neoplasms, submandibular gland
enlargement most commonly is secondary to
chronic inflammation and calculi.
98. n
n
The majority of patients with
salivary gland neoplasms
present with a slowly
enlarging painless mass.
Parotid neoplasms most
commonly occur in the tail of
the gland.
Submandibular neoplasms
often present with diffuse
enlargement of the gland,
while sublingual tumors will
produce a palpable fullness
in the floor of the mouth
99. n
n
n
n
Minor salivary gland tumors will have a varied
presentation depending on the site of origin.
Painless masses on the palate or floor of mouth
are the most common presentation of minor
salivary neoplasm.
Laryngeal salivary gland neoplasms may
produce airway obstruction, dysphagia, or
hoarseness.
Minor salivary tumors of the nasal cavity or
paranasal sinus can present with nasal
obstruction or sinusitis.
Lateral pharyngeal wall protrusions with resultant
dysphagia and muffled voice should raise
suspicion of a parapharyngeal space neoplasm.
100. Clinical Examination
n
n
n
n
Physical examination : of salivary gland masses should occur in
the setting of a thorough general head and neck examination.
Note size, mobility, fixation to surrounding structures, tenderness,
and extent of the mass. Perform bimanual palpation of the lateral
pharyngeal wall for deep lobe parotid tumors to assess for
parapharyngeal space extension. Similarly, bimanual palpation for
submandibular and sublingual masses will reveal the extent of the
mass and will assess fixation to surrounding structures.
Pay attention to surrounding skin and mucosal sites, which drain to
the parotid and submandibular lymphatics. Regional metastases
from skin or mucosal malignancies may present as salivary gland
masses.
A careful neurologic examination focusing on the cranial nerves will
give clues as to neural infiltration and extent of malignant lesions.
101. Facial paralysis:
n
indicates malignancy. The
significance of painful salivary
gland masses is not entirely
clear. Pain may be a feature
associated with both benign and
malignant tumors. Pain may
arise from suppuration or
hemorrhage into a mass or from
infiltration of a malignancy into
adjacent tissue .Facial paralysis
could also occur in non
malignant condition such as
acute suppurative parotitis
109. Pleomorphic Adenoma
( BENIGN TUMOUR )
n Pleomorphic adenoma is the most common
n
n
benign salivary tumor at all sites.
Approximately 80% of all pleomorphic adenomas
occur in the parotid, and despite their slow
growth they can become extremely large if
neglected.
This tumor is thought to arise from both salivary
gland ducts and myoepithelial cells and is a true
“mixed tumor.” Because of its derivation, can
occur, from cellular, glandular, and myxoid types
to cartilagenous and histologically, many
different patterns even ossified forms. These
features can be seen in different areas of the
same tumor, accounting for its name,
pleomorphic (Greek for many forms).
110. n
Plemorphic adenoma is one of the very few
tumors that can undergo change from benign
to malignant . Mixed SG tumors is poorly
encapsulated and had a tendency toward
local recurrence if only enucleated .
113. Warthin’s Tumors (Adenolymphoma )
This benign tumor is almost exclusively found
in the parotid. It occurs mostly in men and is
more common in smokers. It is thought to
derive from salivary duct cells that are
entrapped in lymph nodes during embryonic
development.
n The tumor consists of large cystic spaces
with a surrounding columnar epithelium and a
stroma of lymphocytes. Surgically these
tumors may be multiple in one parotid gland
or bilateral, or involve lymph nodes adjacent
to the parotid gland.
n
114. Salivary Glands
n Mixed
malignant tumour
Long standing pleomorphic adenoma
n Older age group
n Worse prognosis
n Lymph node mets 15%
n Distant mets 30%
n 5 year survival 40% - 50%
n 15% year survival 20%
n
118. Malignant Tumors
Mucoepidermoid carcinoma (MEC) is the
most common malignant salivary gland
neoplasm in both adults and children, and the
most common salivary gland cancer of the
parotid and minor salivary glands. This tumor
can be of low grade or high grade depending on
its histology. Low-grade MECs have multiple
macrocysts and abundant mucus-producing
cells.
n High-grade varieties have multiple squamous
cells and very few mucus-producing cells or
cysts,
n
119. n
The respective ratio of mucus producing
cells to squamous cells will determine the
clinical aggressiveness of the tumor . Lowgrade MECs can be very slow growing
and nonmetastasizing, and can generally
behave like a benign tumor.
n
High-grade MECs can exhibit aggressive
growth and invasion resulting in widespread
metastasis and death. Highgrade tumors
usually show increased pleomorphism and
meiotic figures. High-grade lesions may
metastasize to cervical lymph nodes or
spread hematogenously to the lung, liver,
and bone.
120. n
n
The infiltrative nature of this lesion and the
frequency of perineural involvement with spread
along the nerve mandate wide resection
margins. Perineural spread is a bad prognostic
sign for both local recurrence and distant
metastasis.
Clinical and radiologic examination of this tumor
frequently underestimate its true extent, and
follow-up of 15 to 20 years is required as late
recurrences occur
121. Low-Grade Adenocarcinoma
n Low-grade
adenocarcinoma occurs
almost exclusively in the minor
salivary glands and is second only to
mucoepidermoid carcinoma at these
sites. It arises from terminal duct cells
n
local recurrence will occur with
inadequate excision due to perineural
involvement .
122. Salivary Glands
n
Adenocystic carcinoma (Cylindroma)
n
Commonly involves submandibular (35% - 40%),
only 7% of parotid malignancies
Slowly growing
Perineural invasion
30% lymph node mets, 50% distant mets
5 year survival 75%
10 year survival 30%
20 year survival 13%
n
n
n
n
n
n
128. Parotid Gland
n
n
Site of Tumor
The surgical principles of treating parotid tumors are
dictated by the histopathology of the tumor and the
need to preserve the facial nerve. Diagnostic imaging
with computed tomography (CT) or magnetic
resonance (MR) is desirable for superficial lobe
tumors but is essential for suspected deep-lobe
neoplasms, especially those with a parapharyngeal
component.
Since 80% of parotid tumors are benign and 80% of
these are pleomorphic adenomas, a solitary mass in
the parotid with no features of malignancy is most
likely . Open biopsy of such a mass is therefore
contraindicated as this will rupture the “capsule” and
increasing the complexity of subsequent surgery and
chances of recurrence.
129. Fine-needle aspiration biopsy (FNAB)
for cytology is the preferred method of
diagnosis.
Clinically only one-third of malignant
tumors will have symptoms or signs
of malignancy, such as pain,
ulceration of skin, facial nerve palsy,
or metastatic cervical nodes.
130. n
n
n
Thus virtually all parotid tumors will initially be
treated as benign unless FNAB shows definite
malignancy or there is clinical evidence of
malignancy
The majority of tumors occur in the superficial lobe,
and superficial lobectomy with preservation of the
facial nerve has been the standard operation for
many years. .
Superficial lobectomy is suitable for benign and lowgrade malignant tumors, and even in high-grade
malignancies only branches of the nerve that are
actually infiltrated will be sacrificed. If the nerve or
portions of it have to be resected, immediate grafting
is recommended. In deep-lobe tumors a total
parotidectomy is performed, with the superficial lobe
being dissected first to expose the nerve
131. Good margins with surrounding normal
salivary gland tissue are more difficult to
obtain on deep-lobe tumors, which tend to be
large as they are often detected late. In highgrade tumors, surrounding tissues such as
skin, masseter, and mandible may require
sacrifice, as dictated by the need to obtain
clear margins.
n In these instances consideration should be
given to neck dissection.Where clinically
positive nodes are present, a modified radical
neck dissection is usually the operation of
n In high-grade tumors postoperative radiation
therapy is usually indicated. Chemotherapy
has not been shown to convey a survival
benefit for these lesions.
n
132. n
A, Large neglected pleomorphic
adenoma of the left parotid gland. B,
Axial computed tomography scan
showing tumor in the superficial lobe. C,
Operative photograph showing
superficial parotidectomy with initial
dissection of the upper and lower
branches of the facial nerve trunk.
133. Submandibular Gland
n
n
50% of tumors will be malignant, adenoid cystic
carcinoma being the most common. In benign
neoplasms removal of the submandibular gland
with an extracapsula dissection of the tumor and 2
to 3 mm of surrounding soft tissue is sufficient.
If indicated the overlying platysma superficially
and the mylohyoid muscle deeply will be excised.
In most malignant tumors with N0 necks, the
cervical incision necessary for removal of level I
will dictate extending levels I to III.
134. n
n
The adenoid cystic carcinoma does not usually
metastasize via the lymphatics; this to a
supraomohyoid neck removing instead it spreads
hematogenously and neck dissection may not be
indicated. The mandibular branches of the facial,
lingual, and hypoglossal nerves are all in close relation
to the submandibular gland.
If these nerves appear to be involved by cancer, they
should be traced until the nerve appears normal.After
resection, frozen sections should be sent from the cut
nerve trunk to confirm clearance, although “skip”
lesions do occur. Radiation may be useful
postoperatively.
136. The Retromolar Fossa
n Although this is a relatively unusual site for
minor salivary gland tumors, virtually 100%
are malignant and are low-grade
mucoepidermoid carcinomas. The surgeon
should be aware that a cystic soft tissue
mass distal to the third molar, with or
without radiographic mandibular
involvement, is unlikely to be a mucocele,
and incisional biopsy should be
undertaken to confirm the diagnosis.
.
137. Intrabony Tumors
n
Although intrabony (central) salivary gland tumors
are rare, the vast majority are malignant lowgrade
mucoepidermoid carcinomas.13 These are mostly
seen in the third molar region of the mandible and
are frequently multilocular.
n
The tumors are often diagnosed radiologically as
ameloblastomas, or odontogenic keratocysts.
Resection with a 1 cm margin and sacrifice of the
inferior alveolar nerve and overlying soft tissue in
areas of perforation are required.
138. n
Neck dissection is usually not necessary,
but if the neck has been opened widely for
mandibular resection a supraomohyoid neck
dissection can be undertaken. A
reconstruction plate is placed and either
primary reconstruction with a fibular or deep
circumflex iliac artery microvascular flap or
secondary posterior iliac crest
corticocancellous reconstruction may be
used
139. The Sublingual Gland
n
n
.
Less than 1% of all salivary gland tumors occur in the
sublingual gland but almost 100% are malignant.
Surgical approach will be dictated by the histology
and required access for margins.
In most cases we have preferred a lip split and
mandibulectomy to allow good visualization of the
tumor, direct examination of the mandibular lingual
cortical plate, and the ability to trace back the lingual
nerve when necessary
Other Intraoral Sites
n
Interestingly, the proportion of benign to malignant
tumors varies according to site, with virtually all
upper lip tumors being benign and a higher
proportion of lower lip tumors being malignant.
Salivary gland neoplasms of the tongue and buccal
mucosa tend to be malignant and require wide soft