Imaging of salivary gland tumours

INTRODUCTION
ANATOMY AND
PHYSIOLOGY
IMAGING
METHODS
• BENIGN
• MALIGNANT
NEOPLASMS

Introduction
• Saliva is a clear, alkaline, somewhat viscid
secretion from the parotid, submandibular,
sublingual and smaller mucous glands of the
mouth. - Dorland’s Medical Dictionary
• Saliva is a clear taste less, odorless, slightly acidic,
viscous fluid consisting of secretions from the
parotid, submandibular & mucous glands of oral
cavity. - Stedman’s Medical Dictionary

SALIVARY GLANDS
 MAJOR SALIVARY GLANDS (paired structures):
 PAROTID
 SUBMANDIBULAR (SUBMAXILLARY)
 SUBLINGUAL
 MINOR SALIVARY GLANDS (diffusely scattered in oral cavity):
 BUCCAL (cheek)
 PALATINE (palate)
 LABIAL (lip)
 LINGUAL (tongue)
 Secrete 10% of total volume of saliva
 Account for about 70% of mucus secreted

Parotid
Glands of Von r
Mucous
Serous
Mixed
Labial & Buccal Glands
Glossopalatine
Palatine
Posterior tongue
Submandibular &
Sublingual
Anterior tongue
Parotid
Glands of Von Bender
5
Types of Salivary Glands

Development of Salivary Glands
• Individual salivary glands arise as a proliferation of oral
epithelial cells, forming a focal thickening that grows into
the underlying ectomesenchyme.
• Continued growth results in the formation of a small bud
connected to the surface by a trailing cord of epithelial
cells, with mesenchyme condensing around the bud.
• Clefts develop in the bud, forming two or more new buds;
continuation of this process, called branching
morphogenesis, produces successive generations of buds
and a hierarchical ramification of the gland.

• Parotid glands: begin development at 4-6 weeks IU
• Submandibular glands: 6 weeks IU
• Sublingual and minor glands: 8-12 weeks IU
• The cells of the secretory end pieces and ducts attain
maturity during last two months of gestation.
• The glands continue to grow postnatally, with the
volume proportion of acinar tissue increasing and the
volume proportion of ducts, connective tissue, and
vascular elements decreasing up to 2 years of age.

Parotid Gland
• Para: around; otic: ear
• Largest of the glands, 14-28g.
• Situated below the external acoustic meatus,
between the ramus of the mandible and the
sternomastoid.
• The investing layer of the deep cervical fascia
forms a capsule for the gland – parotid
capsule

• The parotid gland is composed of adipose and glandular tissues in
nearly equal proportions.
• The parotid gland is divided into the larger superficial and smaller
deep lobes by the retromandibular or facial vein.
• It is located posterior to the ramus of mandible and drains via the
Stenson's duct traversing superficial to the masseter muscle and
passing through the buccinator muscle before finally opening into
the oral cavity at the ipsilateral 2ndmaxillary molar.
• The distal part of facial nerve and its terminal branches passes
through the parotid parenchyma.
• Multiple nodes are located superficially and within the parotid
gland.
• Accessory parotid gland is noted in 20% subjects and is usually
located anterior to the main parotid and superior to the Stenson's
duct draining in to the latter through an accessory duct.

External Features
• Resembles a three sided pyramid; the apex of the pyramid is
directed downwards.
• Gland has four surfaces:
– Superior (base of the pyramid)
– Superficial
– Anteromedial, and
– Posteromedial.
• The surfaces are separated by three borders:
– Anterior
– Posterior
– Medial

Relations of the Gland
• APEX:
– It overlaps the posterior belly of the digastric;
– The cervical branch of the facial nerve and the two
divisions of the retromandibular vein emerge through
it.
• SUPERIOR SURFACE:
– Is small and concave,
– Related to cartilaginous part of external acoustic
meatus, posterior part of TMJ, superficial temporal
vessels and auriculotemporal nerve.

• ANTEROMEDIAL SURFACE:
– Grooved by posterior border of ramus,
– Related to the masseter, TMJ, posterior border of
ramus, medial pterygoid muscle, and emerging
branches of facial nerve.
• POSTEROMEDIAL SURFACE:
– Molded to the mastoid & styloid process;
– Related to the sternomastoid and posterior belly of
digastric; styloid process and its structures;
– External carotid artery enters the gland through this
surface.

• SUPERFICIAL SURFACE:
– Covered by skin, superficial fascia with superficial
parotid lymph nodes; parotid fascia, and deep
parotid lymph nodes.
• From the anterior border emerges:
– Parotid duct,
– Terminal branches of facial nerve.

Parotid Duct
• Thick walled, 5cm long.
• Emerges from the middle of the anterior border of the gland.
• Runs forward and slightly downwards on the masseter, where it is related
to the upper and lower buccal branch of the facial nerve, and the
accessory parotid gland.
• At the anterior border of the masseter it turns medially to pierce the
buccal pad of fat, buccopharyngeal fascia and the buccinator to run
forward between the muscle and the oral mucosa.
• Before finally piercing it opposite the crown of the upper second molar.

Blood Supply
• Arterial supply: External carotid artery and its
branches;
• Venous drainage: External jugular vein

Nerve Supply
PARASYMPATHETIC SUPPLY
Inferior salivatory nucleus
9th cranial nerve
Otic ganglion
Auriculotemporal nerve
Gland
SYMPATHETIC SUPPLY
Vasomotor
Plexus around the external
carotid artery

Lymphatic Drainage
• Drains first to the parotid lymph nodes then to
the upper deep cervical lymph nodes

• (a) Diagram shows the location of the Stenon duct. 1 = parotid gland, 2 = Stenon
duct, 4 = masseter muscle, 5 = surface of the mandible, 6 = buccal muscle, large
arrow = retromandibular vein and external carotid artery.(b) Panoramic US
image shows a dilated Stenon duct in a patient with sialolithiasis and
inflammation. 1 = inflamed left parotid gland, 2 = dilated Stenon duct, 3 =
stone, 4 = masseter muscle, 5 = surface of the mandible, 6= buccal muscle, large
arrow = retromandibular vein and external carotid artery.

• This illustration represents a horizontal section through the
lateral portion of the pharynx and mandible at the level of the
mastoid process. The parotid gland is traversed by the facial
nerve, and the deep portion of the gland narrows and is
bounded by the posterior of the ramus of the mandible, muscles
of the styloid process and medial pterygoid muscle. Right:
Tumors that arise within the deep portion of the gland may
expand into the lateral pharyngeal space and produce swelling of
the lateral pharyngeal wall.

• This lateral view of the head
shows the anatomic position
and relationship of the parotid
and submandibular glands to
the ear, zygomatic arch,
mandible and masseter
muscle. The parotid gland duct
(Stensen's duct) crosses the
masseter muscle and
penetrates the buccal tissues.
Lobules of accessory parotid
tissue are located along the
course of the duct.

Non-contrast axial CT
image show normal
appearing parotid (white
arrows) gland in a young
subject

• Also called submaxillary gland
• The submandibular gland is the second largest salivary gland and is
located in the floor of the mouth adjacent to the posterior body of
mandible along the free edge of the mylohyoid muscle.
• Partially enclosed between two layers of the deep cervical fascia.
• In submandibular triangle formed by anterior and posterior bellies of
digastric muscle and inferior margin of mandible
- Weighs 50% of parotid gland
• The amount of adipose tissue is relatively lower than that of parotid gland.
The lingual nerve and submandibular ganglion are noted superficial to the
submandibular gland while the hypoglossal nerve lies deep to it.
• It drains through the Wharton's duct in the anterior sublingual region at
the papilla in paramidline location.

Superficial Part
• It has
– Inferior,
– Lateral, and
– Medial surfaces.

Relations
• INFERIOR SURFACE: covered by
– Skin
– Platysma
– Cervical branch of facial nerve
– Deep fascia
– Facial vein
– Submandibular lymph nodes

• LATERAL SURFACE:
– Submandibular fossa
– Medial pterygoid muscle
– Facial artery
• MEDIAL SURFACE may be divided into three parts:
– Anterior part: related to mylohyoid muscle, nerves and vessels.
– Middle part: hyoglossus, styloglossus, lingual nerve, submandibular ganglion,
hypoglossal nerve
– Posterior part: styloglossus, stylohyoid ligament, 9th nerve.

Deep Part
• Small in size,
• Lies deep to the mylohyoid, and superficial to the hyoglossus and
styloglossus.
• Posteriorly it is continuous with the superficial part around the posterior
border of the mylohyoid;
• Anteriorly it extends up to the posterior end of the sublingual gland.

Submandibular Duct
• Thin walled, 5cm long.
• Emerges at the anterior end of the deep part of the gland
• Runs forward on the hyoglossus between lingual and hypoglossal nerves.
• It opens on the floor of the mouth, on the summit of the sublingual
papilla at the side of the frenulum of the tongue.

Blood Supply and Lymphatic Drainage
• Arterial supply: Facial artery.
• Venous drainage: Common facial or lingual vein.
• Lymph: Passes to the submandibular lymph nodes.

Nerve Supply
PARASYMPATHETIC SUPPLY
Superior salivatory nucleus
7th cranial nerve
submandibular ganglion
CN VII nerve
Gland
SYMPATHETIC SUPPLY
Vasomotor
Plexus around the facial
artery

• (a) US image shows a nondilated Wharton duct (arrow) in a slim patient.
Arrowheads = submandibular gland, 1 = mylohyoid muscle. (b)Diagram
shows the course of the Wharton duct (arrow). Arrowheads =
submandibular gland, 1 = mylohyoid muscle, 2 = sublingual gland.

Sublingual Gland
• Smallest of the three major glands
• Almond shaped and weighs about 3-4 g
• Lies above the mylohyoid muscle and below the mucosa
of the floor of the mouth.
• Medial to the sublingual fossa and lateral to
genioglossus.

Sublingual gland
• The Wharton's duct and lingual nerve separate the
sublingual gland from the medial genioglossus
muscle.
• It opens via multiple ducts usually 20 in number
(known as ducts of Rivinus) directly into the floor of
mouth along sublingual papillae and folds.
• Occasionally, some of the ducts unite to form the
Bartholin's duct that drain into the Wharton's duct.

• 15 ducts emerge from the gland, most of
which open directly into the floor of the
mouth.
• A few join the submandibular duct.
• Blood supply: from lingual and submental
arteries.
• Nerve supply is same as that for
submandibular gland.

Minor salivary glands
• - Except for the gingiva and anterior hard palate,
minor salivary glands (500-1000, 1-5 mm each)
are located throughout the submucosa of the oral
cavity
- More numerous in posterior hard palate
- Each salivary unit has its own simple duct
- Most of these minor salivary glands are
mucinous with the main exception of Ebner’s
glands which are serous glands located in the
circumvallate papillae of the tongue

Innervation
• Salivary glands are innervated, either directly or indirectly, by
the parasympathetic and sympathetic arms of the autonomic nervous
system. Both result in increased amylase output and volume flow.
• Parasympathetic innervation to the salivary glands is carried via cranial
nerves. The parotid gland receives its parasympathetic input from
the glossopharyngeal nerve (CN IX) via the otic ganglion, while the
submandibular and sublingual glands receive their parasympathetic input
from the facial nerve (CN VII) via the submandibular ganglion.
• Direct sympathetic innervation of the salivary glands takes place via
preganglionic nerves in the thoracic segments T1-T3 which synapse in
the superior cervical ganglion with postganglionic neurons that release
norepinephrine, which is then received by β-adrenergic receptors on the
acinar and ductal cells of the salivary glands, leading to an increase in
cyclic adenosine monophosphate (cAMP) levels and the corresponding
increase of saliva secretion.

SALIVARY GLAND FUNCTION
 SECRETION OF SALIVA
• DIGESTIVE ENZYMES
• MOISTENING OF FOOD
• PROTECTIVE FUNCTION

PATHOLOGY AND IMAGING
• The common clinical indications of salivary gland imaging are
pain and swelling.
• Imaging is useful in identifying the masses of salivary glands
and also in differentiating them from the masses/pathologies
of adjacent cervical spaces, especially parapharyngeal,
masticator, and submental spaces and mandibular lesions.
• Nodal masses, peripheral nerve schwannomas, and
masseteric hypertrophy may mimic tumors of salivary glands
clinically.

• In proven cases of salivary gland tumors, imaging helps in
delineating the extent of the lesion and invasion of adjacent
cervical spaces, skull base, mandible, and nerves/meninges.
• The disease of major salivary gland can be broadly categorized
into the inflammatory, neoplastic, systemic, and congenital
conditions.

Imaging Armamentarium for Salivary Gland Imaging
Includes:
• Plain radiography
• Sialography (conventional, CT, MRI)
• High-resolution ultrasonography (HRUS)
• Computed tomography (CT)
• Magnetic resonance imaging (MRI)
• Radionuclide scintigraphy
Referrence:Pictorial essay: Salivary gland imaging Rajul Rastogi , et al.,

Plain Radiography
• This is the simplest, oldest, and cheapest way of studying the
salivary glands. It is useful in detecting ductal calculi,
calcifications (as in hemangioma and lymph nodes), and
adjacent osseous lesions. Only one-fifth of the salivary ductal
calculi are radiolucent.
• Parotid gland radiography requires posteroanterior projection
with extended chin, open mouth, and cheeks blown out to
delineate Stenson's duct lesion.
• Submandibular gland radiography requires posteroanterior
and ipsilateral oblique projection with extended chin, open
mouth, and tongue depressed by patients’ finger

• Plain radiograph of the submandibular region in AP (A) and
lateral oblique (B) projection showing soft tissue swelling
associated with a small calculus (arrow) visible on lateral
oblique view taken with depressed tongue

Sialography
• It refers to the evaluation of the ductal system of the salivary
glands. It is considered the gold standard technique for
studying the ductal morphology.
• It is commonly used for parotid and submandibular glands
and its main indication is chronic sialadenitis unrelated to
sialolithiasis.
• Acute sialadenitis is a contraindication for sialography.
Irregular pooling of contrast and ductal obstruction without
presence of calculus are indirect signs of malignancy.

• Sialography is rarely used for sublingual imaging
because of numerous small ducts opening directly
into the floor of mouth.
• Sublingual glands may however be visualized in an
anatomic variation where the Bartholin's duct is
outlined following injection of the contrast medium
into the Wharton's duct.

• This test is performed by injecting oil / water soluble iodine containing
contrast solution into the Stenson’s / Wharton’s duct.
• Water soluble diatrizoate meglumine and iodipimide meglumine are
preferred because of their low viscosity and ease of injection. Water
soluble agents also cause very little foreign body reaction.
• This imaging modality is very rarely used in sublingual imaging because
the ducts are numerous and small.
• They open directly to the floor of the mouth. Sublingual Sialography is
possible only in patients with anatomic variations like filling up of
Bartholin’s duct from injection of Wharton’s duct during submandibular
Sialography.
• Since about 80% of salivary gland calculi are radio opaque, plain film study
is a must before Sialography.

Procedure:
• Stenson’s duct / Wharton’s duct is progressively dilated
gently. Infiltration of local anesthetic agent may be
necessary. Sialographic canula is connected to a contrast
laden syringe and is inserted into the duct. After
fluoroscopically verifying the position of the canula, the
contrast material is slowly injected. Irregular contrast pooling
and ductal obstruction are considered features of malignancy.

• Conventional sialography
of submandibular (A)
and parotid glands (B)
showing ductal system

• However, 3DCT performed especially with cone-beam CT
following injection of the contrast medium into the ductal
system without intravenous injection of contrast can provide
images similar to or better than conventional sialography and is
often referred to as CT sialography.
• MR Sialography, by contrast, delineates the ductal system of
the gland without injection of ductal/intravenous contrast by
utilizing the highly fluid-sensitive sequences similar to that
used for magnetic resonance cholangiopancreatography
(MRCP).
• MR Sialography can be performed in patients of acute
sialadenitis. Prior administration of a sialogogue agent may
improve ductal visualization in MR Sialography.
• MR Sialography has poor spatial resolution as compared to
conventional sialography.

• MR sialography shows
bilateral Stemson's duct
(arrows)

High-resolution Ultrasonography
• It is a quick and noninvasive method of evaluating parotid and
submandibular glands. Both glands appear homogeneously hyperechoic
on HRUS, and retromandibular vein can be noted within the parotid gland.
• It is performed by a high-frequency linear (7-10 MHz) transducer.
• It helps in differentiating cystic from solid lesions and also aids in guiding
the exact site of Fine N eedle A spiration C ytology (FNAC) in suspected
salivary gland lesions.
• It fails to demonstrate the parotid gland in its entirety because of
intervening mandible. It also does not clearly demonstrate the
intraglandular facial nerve branches.

• HRUS images
showing normal
parotid and
submandibular
glands (top row)
and
retromandibular
vein in the parotid
gland (arrow)

• When combined with color Doppler imaging, it helps in assessing
the vascularity and nature of the lesion (malignant lesions of
salivary glands are highly vascular as compared to their benign
counterparts – peripheral vascularity with hypovascular central area
in the tumoral lesion is highly suggestive of pleomorphic adenoma).
• RI and PI values of greater than 0.7 and 1.2, respectively, coupled
with high PSV (greater than 44.3 cm/s), ill-defined margins, and
nodal involvement with central vascularity are highly indicative of
malignant salivary gland lesion

• In experienced hands, it helps in differentiating intra-parotid
nodes from true intraparenchymal lesions, picking soft
calcifications/diffuse lesions and detecting major ductal
dilatation with intraductal calculi.
• However, it cannot optimally evaluate the deep lobe of the
parotid gland.
HRUS images show altered echopattern of the parotid gland with ductal
dilatation (thin arrow) and small calculus (thick arrow) at its terminal end

CT and MRI
• These cross-sectional studies help in true and near complete
imaging of the salivary glands.
• MRI, because of its multiplanar capability and higher soft
tissue resolution, has an upper hand over CT in demonstrating
the extent of lesion and their perineural/meningeal spread.
• However, CT (especially cone-beam CT) demonstrates the
osseous lesions/extension and calcification/calculus better
than MRI.
• Noncontrast CT may be enough in cases of sialolithiasis.
However, ductal system is not optimally evaluated by any of
these techniques.

• Non-contrast axial CT
image showing
submandibular
sialolithiasis on right
side (white arrow) and
normal gland on left
side

• Non-contrast
T2W axial &
coronal images
(top row) and
T1W axial and
coronal images
showing parotid
(thick white
arrows) and
submandibular
glands (thin
white arrow)

• These studies are often performed after intravenous injection of the
contrast media for better delineation of the anatomy and the extent of
lesion.
• Diffusion-weighted (DW) images and gadolinium-enhanced dynamic MR
(Gd-MRI) imaging have proven to be very useful in differentiating benign
from malignant tumors.
• DW images can be used to calculate apparent diffusion coefficient (ADC)
values, which are different for different salivary gland tumors.

• Gd-MR with dynamic imaging using 120 s as cut-off for time to peak
enhancement and 30 % wash-out ratio can differentiate benign and
malignant tumors as the latter take less time for peak enhancement and
show rapid wash-out.
• Plateau type of time–intensity curve in dynamic Gd-MR coupled with low
ADC values is also highly suggestive of malignancy.
• Proton MR Spectroscopy has also been described for differentiation of
benign from malignant tumors by some authors.
• Choline/creatinine ratios are significantly lower in malignant than in
benign salivary gland tumors.

PET Scan
• Very sensitive for metastatic LN < 8mm
• Helpful for previously treated H + N cancers
• Positron emission tomography (PET) imaging using 2-deoxy-2-[18F]
fluoro-d -glucose (FDG) can be used to differentiate benign from
malignant tumors of the salivary glands as the former appear as cold
spots with the exception of Warthin's tumor and oncocytoma
PET/CT Scan
• Has increased value in salivary gland tumour staging
• Pittsburgh study(55pts) showed
• sensitivity of 74.4%
• specificity of 100%
Angiography or MRI-Angio
• Can be used to assess carotid artery involvement

Radionuclide Imaging
• It is a rarely used technique for salivary gland imaging. Sodium
pertechnetate (Tc[99]) is actively concentrated and secreted by salivary
gland cells while it is not taken up by majority of neoplastic lesions, hence
the latter appear as cold spots. Warthin's tumor is an exception to the rule
and appears as a hot spot.
• Actively dividing cells take up Gallium-67; hence it is useful in detecting
diffuse inflammatory/neoplastic processes such as sarcoidosis and
lymphoma.

Salivary Gland Neoplasms
• Diverse histopathology
• Relatively uncommon
– 2% of head and neck neoplasms
• Distribution
– Parotid: 80% overall; 80% benign
– Submandibular: 15% overall; 50% benign
– Sublingual/Minor: 5% overall; 40% benign

Staging
• AJCC Cancer Staging Manual (sixth edition)
• Based on tumor size, local extension of tumor,
nodal metastasis, and distant metastasis
• Histologic grade, patient age, and tumor site
are important additional factors that should
be considered in future staging systems

TNM
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor 2 cm or less in greatest dimension without gross
extraparenchymal extension
T2 Tumor more than 2 cm but not more than 4 cm in greatest
dimension without gross extraparenchymal extension
T3 Tumor more than 4 cm and/or tumor having gross
extraparenchymal extension
T4a Tumor invades skin, mandible, ear canal, and/or facial nerve
T4b Tumor invades skull base and/or pterygoid plates and/or encases
carotid artery

TNM
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in
greatest dimension
N2a Metastasis in a single ipsilateral lymph node, more than 3 cm but
not more than 6 cm in greatest dimension
N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6
cm in greatest dimension
N2c Metastasis in bilateral or contralateral lymph nodes, none more
than 6 cm in greatest dimension
N3 Metastasis in a lymph node more than 6 cm in greatest dimension

TNM
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis

Stage Grouping
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T3 N0 M0
T1 N1 M0
T2 N1 M0
T3 N1 M0
Stage IVA T4a N0 M0
T4a N1 M0
T1 N2 M0
T2 N2 M0
T3 N2 M0
T4a N2 M0
Stage IVB T4b Any N M0
Any T N3 M0
Stage IVC Any T Any N M1

Histologic Grade
• Histologic grading is applicable only to some
types of salivary gland cancer
(mucoepidermoid carcinoma,
adenocarcinoma not otherwise specified)
• In most instances, the histologic type defines
the grade (i.e. salivary duct carcinoma is high
grade, basal cell adenoma is low grade)

• Benign Neoplasms
– First branchial cleft cysts
– Hemangiomas
– Lymphangiomas
– Pleomorphic adenomas
• Carcinoma ex pleomorphic adenoma
• Carcinosarcoma
• Metastasising mixed tumour
– Warthins tumour
– Rare
• Oncocytomas
• Myoepitheliomas
• Monomorphic adenomas
• Basal cell carcinoma
– Lipomas

First branchial cleft cysts
First branchial cleft cysts typically manifest in middle aged women with
a history of recurrent parotid gland infection unresponsive to
antibiotics. Occasionally a fistula can be observed at the angle of the
mandible.
First branchial cleft cysts account for 8% of all branchial complex
anomalies. These cysts occur in or directly adjacent to the parotid
gland.
At ultrasound (US) these cysts may look solid due to internal
haemorrhage or infection. Colour Doppler does not show any flow
suggesting the cystic nature of the lesion.
At CT or MRI, after administration of contrast medium, the cyst wall
may be thickened and enhance due to infection. Increased signal
intensity on T1-weighted sequences suggests prior bleeding or
infection.

Haemangiomas
Haemangiomas manifest as unilateral parotid swelling shortly
after birth. A bluish discoloration of the skin can often be seen.
These lesions are the most common benign salivary gland
masses in children with a female predilection.
They are classified as capillary or cavernous at pathology. About
90% represent congenital capillary haemangiomas which
spontaneously regress until adolescence. Cavernous
haemangiomas are rare, manifest in older children and do not
undergo resolution.
At CT or MRI, capillary haemangiomas are seen as welldefined
masses with strong enhancement. Flow voids due to prominent
vasculature are often present in or around the mass.

Axial grey-scale ultrasound shows
a solid, hypoechoic, well-circumscribed mass
(arrows) involving superficial and deep lobes of
the parotid gland.
Power Doppler ultrasound shows marked
vascularity within the mass, consistent with
hemangioma.

Transverse section of the masseter muscle reveals a hypoechoic, compressible vascular
mass : diagnosis - hemangioma

T1-weighted axial (A) and T2-weighted axial images with fat saturation demonstrate
enlargement and replacement of the left parotid gland by a cystic-appearing lesion.
The lesion remains well encapsulated and has an enlarged flow void in the
retromandibular vein consistent with a hemangioma

Lymphangiomas
Lymphangiomas are congenital malformations of the
lymphatic system with an incidence of 90% at the age of
2 years. Infection or haemorrhage may occur; however
in contrast to haemangiomas spontaneous regression is
rare.
At imaging lymphangiomas consist of cystic areas
and thin septations, but also solid enhancing portions.
Haemorrhage can lead to fluid levels with variable signal
intensities depending on the duration of the bleeding.

Hypoechoic, septated, compressible lesion with no detectable flow on Colour Doppler
assessment Lymphangioma of the neck was histologically proven.

CT scan (A) and T2-weighted MR image (B) with fat saturation demonstrate a cystic,
nonenhancing lesion replacing the left parotid gland.
There is extension beyond the capsule into the floor of the mouth and into a
retropharyngeal location consistent with a lymphangioma.

Pleomorphic Adenoma
• Most common of all salivary gland
neoplasms
– 70% of parotid tumors
– 50% of submandibular tumors
– 45% of minor salivary gland tumors
– 6% of sublingual tumors
• 4th-6th decades
• F:M = 3-4:1
• The alternative term, mixed tumours, is
attributed to the histological heterogeneity
suggesting a variety of imaging findings
• Slow-growing, painless mass
• Parotid: 90% in superficial lobe, most in tail
of gland
• Minor salivary gland: lateral palate,
submucosal mass

There are three malignancies associated with pleomorphic adenoma:
(1) The carcinoma ex-pleomorphic adenoma:
– The carcinoma ex-pleomorphic adenoma is a malignant change of a benign
mixed tumour or a malignant tumour in a patient who previously underwent
surgery for a pleomorphic adenoma.
– Carcinoma ex-pleomorphic adenomas have a high metastatic rate varying
from 25% to 76% into regional lymph nodes, lungs, bones and brain
(2) The rarer variant, the true malignant mixed tumour (carcinosarcoma):
– The carcinosarcoma is rare and has a bad prognosis.
(3) The metastasising mixed tumour:
– The metastasising ‘benign’ mixed tumour is the rarest variant.
– Metastases may be multiple and occur in the lung, bone and soft tissue, often
over decades.
Small benign mixed tumours are usually hypointense in T1- and hyperintense in T2-
weighted sequences. Inhomogeneity is seen in larger tumours, whereas low signal
intensity on T2-weighted images may be observed in carcinoma ex-pleomorphic
adenomas.

• Gross pathology
– Smooth
– Well-demarcated
– Solid
– Cystic changes
– Myxoid stroma
• Histology
– Mixture of epithelial, myopeithelial and
stromal components
– Epithelial cells: nests, sheets, ducts,
trabeculae
– Stroma: myxoid, chrondroid, fibroid, osteoid
– No true capsule
– Tumor pseudopods

Imaging findings:
• Usually depend on tumour size.
• Small tumours
– more homogeneous and well defined
– strong enhancement after contrast medium administration
in CT and MRI.
• Larger tumours
– pedunculated outgrowth from the main lesion (lobulated
contour)
– more heterogeneous including necrotic and haemorrhagic
areas.
• The recurrence rate varies between 1% - 50% depending on
the initial surgical procedure.
• Recurrences are often multiple and clustered.

• Radiographic features
– Although findings do depend on tumour size, in general they are well
circumscribed rounded masses, most commonly located within the parotid
gland.
– When they arise from the deep lobe of the parotid they can appear entirely
extraparotid, seen in the parapharyngeal space, without a fat plane between it
and the parotid, and widen the stylomandibular tunnel.
– Pleomorphic adenomas can also arise from salivary rest cells in the
parapharyngeal space itself without connection to the parotid gland.
• Ultrasound
– Typically hypoechoic. May show a lobulated distinct border +/- posterior
acoustic enhancement.
– Ultrasound is also useful in guiding biopsy (both FNAC and core biopsies) but
needs to be carried out with care to avoid facial nerve damage .
• Doppler
– Vascularization in pleomorphic adenomas is often poor or absent (even when
the sensitive power Doppler mode is used) but may be abundant. After
inadequate surgery, pleomorphic adenomas often recur, usually multifocally

Longitudinal section through the left parotid gland demonstrates a lobulated mass in the
superficial lobe of the gland distorting the capsule. There is associated distal acoustic
enhancement. Note marked heterogeneity of internal architecture. Biopsy confirmed this
lesion to represent a pleomorphic
adenoma. The mandible is indicated by arrowheads.

Ultrasound image shows well defined hypoechoic structure with slightly lobular contours,
increased through-transmission of ultrasound and mild vascularity.

CT
Smoothly marginated or lobulated homogeneous small spherical mass is the
most common appearance. When larger they can be heterogeneous with foci
of necrosis. Small regions of calcification are common 1.
When small enhancement tends to be prominent. In larger tumours
enhancement is less marked, but can demonstrate delayed enhancement.
MRI
They are commonly seen as well-circumscribed and homogeneous when small.
Larger tumours may be heterogeneous.
T1 - usually of low intensity
T2
usually of very high intensity (especially myxoid type) 6
often have a rim of decreased signal intensity on T2-weighted images
representing the surrounding fibrous capsule
T1 C+ (Gd) - usually demonstrates homogeneous enhancement
Angiography (DSA)
Typically hypovascular.

(a) Transverse early phase helical CT scan shows multinodular heterogeneous enhancement of the
mass.
The central portion (short arrows) of the mass is more strongly enhanced than is the peripheral area
(long arrow) of the mass. (b)Transverse delayed phase CT scan shows slightly increased
enhancement of the two parts of the tumor, which are labeled as in a. (c) Coronal image obtained 7
minutes after contrast material injection shows that the multinodular enhancement of the tumor
(arrows) has disappeared and become homogeneous.

Pleomorphic Adenoma
• Treatment: complete surgical excision
– Parotidectomy with facial nerve preservation
– Submandibular gland excision
– Wide local excision of minor salivary gland
• Avoid enucleation and tumor spill

Warthin’s Tumor
• AKA: (adenolymphoma or papillary
cystadenoma lymphomatosum)
• 6-10% of parotid neoplasms
• Older, Caucasian, males
• 10% bilateral or multicentric
• 3% with associated neoplasms
• Presentation: slow-growing, painless mass

• Warthin tumours present as well-circumscribed
partly cystic, partly solid lesions in CT or MRI,
often located in the tail of the parotid gland.
• Enhancement after contrast medium
administration is often relatively poor.
• In the differential diagnoses of multiple lesions,
metastases, lymphoma or inflammatory
disease must be considered.

Gross pathology
• Encapsulated
• Smooth/lobulated surface
• Cystic spaces of variable size, with
viscous fluid, shaggy epithelium
• Solid areas with white nodules
representing lymphoid follicles
Histology
• Papillary projections into cystic
spaces surrounded by lymphoid
stroma
• Epithelium: double cell layer
– Luminal cells
– Basal cells
• Stroma: mature lymphoid
follicles with germinal centers

Warthin tumor in the parotid gland in a 45-year-old man. (a) Transverse early phase
helical CT scan shows a well-defined mass (arrows) in the left parotid gland. There is
strong enhancement of the tumor with central low attenuation suggestive of a cystic or
necrotic area. (b) Transverse delayed phase scan shows decreased enhancement of
the tumor (arrows).

Bilateral Warthin tumors. Bilateral parotid masses (arrows) are seen on this transverse,
contrast material–enhanced, fat-saturated T1-weighted spin-echo (SE) (750/30
repetition time msec/echo time msec]) MR image. The multiplicity and location at the
tail of the parotid gland (near the lower mandible) are typical features of this tumor

Proton density-weighted (2000/30) MR image shows a 1-cm lesion (arrow) in
superficial aspect of left parotid gland.

• Other benign tumours, such as oncocytomas,
myoepitheliomas, monomorphic adenomas and basal
cell adenomas, are relatively rare benign tumours of
the parotid gland and lack typical imaging patterns.
• Lipomas, however, can easily be diagnosed by CT or
MRI thanks to their fat content with typical low
attenuation values on CT and signal intensities
isointense to fat on all pulse sequences on MR
imaging.

Oncocytoma
• Rare: 2.3% of benign salivary tumors
• 6th decade
• M:F = 1:1
• Parotid: 78%
• Submandibular gland: 9%
• Minor salivary glands: palate, buccal mucosa,
tongue

Oncocytoma
• Presentation
– Enlarging, painless mass
• Technetium-99m pertechnetate scintigraphy
– Mitochondrial hyperplasia

Oncocytoma
• Gross
– Encapsulated
– Homogeneous, smooth
– Orange/rust color
• Histology
– Cords of uniform cells and
thin fibrous stroma
– Large polyhedral cells
– Distinct cell membrane
– Granular, eosinophilic
cytoplasm
– Central, round, vesicular
nucleus

A left parotid oncocytoma in a 68-
year-old woman.
CT scan reveals a large deformable
tumor (white asterisk), which extends
medially into the parapharyngeal
space through the stylomandibular
gap.
The contour of the tumor is distorted
by the styloid process (black arrow)
and the left medial pterygoid muscle
(black arrowheads).

Monomorphic Adenomas
• Monomorphic adenomas include basal cell
adenoma, clear cell adenoma, glycogen-
rich adenoma, and other rare tumors.
• Treatment consists of resection with a
margin of normal tissue.

Basal cell adenoma Canalicular adenoma
Rarity Most common (1.8%) Relatively less common
Age 6th decade 7th decade
Sex (M:F) 1:1 1:1.8
Location Most commonly parotid and
minor salivary glands of upper lip
Minor salivary glands of
upper lip (74%)
Presentation Painless submucosal mass
Characteristics Well circumscribed and
encapsulated mass
• Solid type: solid nests of
tumour cells present.
• Trabecular type: cells in
trabecular pattern with
vascular stroma
• Tubular type: Multiple duct-
like structures and vascular
stroma
Well circumscribed with
multiple foci
Tubular structures line by
columnar or cuboidal cells
with vascular stroma
Radiological features lack typical imaging patterns lack typical imaging patterns

A 59-year-old woman with a palpable mass in the left parotid
region.
Contrast-enhanced axial CT scan shows a round, well-defined mass in
the superficial lobe of left parotid gland with homogeneous
enhancement

Myoepithelioma
• <1% of all salivary neoplasms
• 3rd-6th decades
• F>M
• Minor salivary glands > parotid >
submandibular gland
• Presentation: asymptomatic mass

Precontrast axial CT scan shows a round, well-defined mass (27.39 HU)
in the superficial lobe of the right parotid gland abutting on the capsule
of gland (arrow). B, Contrast-enhanced axial CT scan shows the mass
(102.11 HU) with homogeneous strong enhancement (arrow)

Precontrast axial CT scan shows an indistinct margin mass in the
superficial lobe of the left parotid gland abutting on the capsule of the
gland with calcification (arrow). B, Contrast-enhanced axial CT scan shows
the mass with inhomogeneous enhancement. It contains a central
enhancing nodule (small black arrow) and a nonenhancing peripheral
cystic component (white arrow)

MALIGNANT NEOPLASMS
• Mucoepidermoid carcinoma
• Adenoid cystic carcinoma
• Acinic cell carcinoma
• Polymorphous low grade adenocarcinoma
• Adenocarcinoma
• Primary squamous cell carcinoma
• Salivary duct carcinoma
• Primary lymphoma
• Godwin’s tumor
• Metastases

Mucoepidermoid Carcinoma
• Most common salivary gland malignancy
• 5-9% of salivary neoplasms
• Parotid 45-70% of cases
• Palate 18%
• 3rd-8th decades, peak in 5th decade
• F>M
• Caucasian > African American

• Presentation
– Low-grade: slow growing, painless mass
– High-grade: rapidly enlarging, +/- pain
– **Minor salivary glands: may be mistaken for
benign or inflammatory process
• Hemangioma
• Papilloma
• Tori

• Gross pathology
– Well-circumscribed to
partially encapsulated
to unencapsulated
– Solid tumor with cystic
spaces

Lateral view of a parotid sialogram shows
a mass that has caused ductal erosion and
lack of parenchymal filling.
These findings suggest a high-grade
malignancy.
This patient had a highgrade MEC.

Mucoepidermoid carcinoma of the
parotid gland.
Transverse CT scan shows an
ill-defined mass (C) that has less
attenuation than that of enhancing
parotid tissue in the right parotid
gland.

• Treatment
– Influenced by site, stage, grade
– Stage I & II
• Wide local excision
– Stage III & IV
• Radical excision
• +/- neck dissection
• +/- postoperative radiation therapy

Adenoid Cystic Carcinoma
• Overall 2nd most common malignancy
• Most common in submandibular, sublingual
and minor salivary glands
• M = F
• 5th decade
• Presentation
– Asymptomatic enlarging mass
– Pain, paresthesias, facial weakness/paralysis

• Gross pathology
– Well-circumscribed
– Solid, rarely with cystic
spaces
– infiltrative

Histology
• Cribriform pattern
– Most common
– “swiss cheese” appearance
• Tubular pattern
– Layered cells forming duct-like
structures
– Basophilic mucinous substance
• Solid pattern
– Solid nests of cells without
cystic or tubular spaces

A coronal T1 weighted MR images (repetition
time/echo time (TR/TE) = 500/15) of the
sublingual gland tumour.
The margin of the tumour is well-defined and
the tumour is composed of cystic and solid
components. The solid area (lingual side) of
the tumour shows isointense to the
surrounding muscle and extends into the
hyperintense cystic area.
A coronal fat-saturated T2 weighted image
(TR/TE = 3500/96). The tumour is
circumscribed by a hypointense fibrous
capsule. The signal intensity of the tumour is
heterogeneous

• Treatment
– Complete local excision
– Tendency for perineural invasion: facial nerve sacrifice
– Postoperative XRT
• Prognosis
– Local recurrence: 42%
– Distant metastasis: lung
– Indolent course: 5-year survival 75%, 20-year survival
13%

Acinic Cell Carcinoma
• 2nd most common parotid and pediatric malignancy
• 5th decade
• F>M
• Presentation
– Solitary, slow-growing, often painless mass
• Tumors occur in several configurations, including cystic,
papillary, vacuolated, or follicular

Acinic Cell Carcinoma
• Gross pathology
– Well-demarcated
– Most often
homogeneous

• Treatment
– +/- postoperative XRT
• Prognosis
– 5-year survival: 82%

Salivary duct carcinoma
• Uncommon but highly aggressive malignant tumour
• Mainly of the parotid gland
• Male predilection
• Perineural spread as well as lymph node involvement (70%) are frequent
findings observed in this particular tumour type.
• MR features: Ill-defined margins and low to moderately high signal
intensity on T2-weighted images could be observed in all patients on MR
imaging.
• Differential diagnosis to a benign salivary gland cyst can be difficult on
non-contrast images only.

Axial CT scan showing no mass lesion in right submandibular gland (white arrow) but
multiple metastatic nodes in right upper neck (open arrows). (B and C) 8F-FDG PET scans
showing focal 18F-FDG uptake in submandibular area (black arrow) as well as on right side
of upper neck (open arrows).
Salivary duct carcinoma of 1.7 cm arising in right submandibular gland, with multiple
cervical metastases, was demonstrated histologically after surgery. (D) Newly diagnosed
lung metastasis (arrow) 10 mo after surgery and postoperative radiotherapy.

Polymorphous Low-Grade Adenocarcinoma
• 2nd most common malignancy in minor salivary glands
• 7th decade
• F > M
• Painless, slowly growing, indolent, submucosal mass
• Soft tissue of the palate followed by the lips, buccal mucosa,
tongue, floor of the mouth and pharynx are the most affected
areas.
• The main histological aspects of PLGA are cytological uniformity and
a broad spectrum of growth patterns within the same lesion.
• These growth patterns are represented by lobular, cribriform,
tubular, trabecular, papillary and cystic structures.

Squamous Cell Carcinoma
• 1.6% of salivary gland neoplasms
• 7th-8th decades
• M:F = 2:1
• MUST RULE OUT:
• High-grade mucoepidermoid carcinoma
• Metastatic SCCA to intraglandular nodes
• Direct extension of SCCA
• This malignancy occurs more often in the
submandibular gland than the parotid gland.

• Gross pathology
– Unencapsulated
– Ulcerated
– Fixed
– firm indurated mass

• Proper diagnosis of squamous cell carcinoma requires exclusion
of contiguous spread of a squamous cell carcinoma into the
gland, metastases to the gland, and high-grade mucoepidermoid
carcinoma.
• There is a high incidence of regional and distant metastases.
• The prognosis for squamous cell carcinoma of the salivary gland is
poor.
• Therapy consists of complete surgical resection and
postoperative radiation therapy.

The typical imaging features are necrotic areas in solid tumours best recognised in
fat suppressed T1- weighted MR images after administration of contrast medium
or in enhanced CT images.

Axial contrast-enhanced CT scan shows a necrotic right parotid mass that has
infiltrated the entire gland and the adjacent masseter muscle. This patient had an
SCC of the parotid gland.

• Treatment
– Radical excision
– Neck dissection
• Prognosis

Adenocarcinoma
• Rare
• 5th to 8th decades
• F > M
• Parotid and minor
salivary glands
• Presentation:
– Enlarging mass
– 25% with pain or facial weakness

Adenocarcinoma most commonly occurs in the minor salivary glands, followed by the
parotid gland.
This neoplasm represents approximately 15% of malignant parotid neoplasms.
Adenocarcinomas usually present as a palpable mass.
They behave aggressively with a strong propensity to recur and metastasize.
Grossly, adenocarcinoma is firm or hard and attached to the surrounding tissue.
Microscopically, the cylindric cells of variable height form papillae, acini, or solid
masses.
Adenocarcinoma can be differentiated from mucoepidermoid carcinoma by the lack of
keratin staining.
The degree of glandular formation has been used as a means of grading these tumors.

Adenocarcinomas can be classified according to
their histological findings:
• grade 1 tumours are circumscribed and
minimally invasive
• grade 2 tumours are in between grade 1 and
grade 3
• grade 3 tumours are more solid with a greater
mitotic rate

• Treatment
– Neck dissection
• Prognosis
– Local recurrence: 51%
– Regional metastasis: 27%
– Distant metastasis: 26%
– 15-year cure rate:
– Stage I = 67%
– Stage II = 35%
– Stage III = 8%

Malignant Mixed Tumors
• Carcinoma ex-pleomorphic adenoma
• Carcinoma developing in the epithelial component
of preexisting pleomorphic adenoma
• Carcinosarcoma
• True malignant mixed tumor—carcinomatous and
sarcomatous components
• Metastatic mixed tumor
• Metastatic deposits of otherwise typical
pleomorphic adenoma

Carcinoma Ex-Pleomorphic Adenoma
• 2-4% of all salivary gland neoplasms
• 4-6% of mixed tumors
• 6th-8th decades
• Parotid > submandibular > palate
• Risk of malignant degeneration
• 1.5% in first 5 years
• 9.5% after 15 years
• Presentation
• Longstanding painless mass that undergoes sudden
enlargement

Carcinoma Ex-Pleomorphic
Adenoma
• Gross pathology
– Poorly circumscribed
– Infiltrative
– Hemorrhage and
necrosis

There is a large, nonhomogeneous
mass in the left submandibular
gland.
Septations are present within the
mass, and there is a lobulated
contour.
This was a carcinoma ex
pleomorphic adenoma.

Carcinoma Ex-Pleomorphic Adenoma
• Treatment
– Neck dissection (25% with lymph node
involvement at presentation)
• Prognosis
– Dependent upon stage and histology

Carcinosarcoma
• Rare: <.05% of salivary gland neoplasms
• 6th decade
• M = F
• Parotid
• History of previously excised pleomorphic
adenoma, recurrent pleomorphic adenoma
or recurring pleomorphic treated with XRT
• Presentation

Carcinosarcoma
• Gross pathology
– Poorly circumscribed
– Infiltrative
– Cystic areas
– Hemorrhage, necrosis
– Calcification

A 55-year-old woman with
carcinosarcoma
of tonsillar minor salivary gland
origin.
CT scan of the head and cervical region
shows a large, 6.0 3 6.2 3 7.5-cm,
heterogeneously enhancing mass
obstructing the oropharynx. The mass
involves the soft palate and extends into
the left parapharyngeal and pharyngeal
mucosal spaces, the masticator space,
and the prevertebral space. The mass
abuts the left carotid space, posteriorly
displacing the left internal and external
carotid arteries (arrows). No
lymphadenopathy is seen

Contrast-enhanced T1-weighted MR image (500/25/1), of the mass shows moderate
homogeneous enhancement

Carcinosarcoma
• Treatment
– Neck dissection
– Chemotherapy (distant metastasis to lung,
liver, bone, brain)
• Prognosis
– Poor, average survival less than 2 ½ years

Clear Cell Carcinoma
• AKA glycogen-rich
• Palate and parotid
• 6th-8th decade
• M = F
• Histology
• Uniform, round or
polygonal cells
• Peripheral dark nuclei
• Clear cytoplasm
• Treatment
• Complete local excision

Epithelial-Myoepithelial Carcinoma
• < 1% of salivary neoplasms
• 6th-7th decades, F > M,
parotid
• ? Increased risk for 2nd
primary
• Histology
• Tumor cell nests
• Two cell types
• Thickened basement
membrane
• Treatment
• Surgical excision

Primary lymphoma
• Rare
• Can only be diagnosed if there is no evidence of intra-or extraglandular
nodal involvement.
• These lymphomas are considered as extranodal marginal zone B-cell
lymphomas.
• Incidence: 1 and 8% of the patients with lymphomas
• All forms of Hodgkin’s and non-Hodgkin’s lymphomas have been reported.
• In the case of secondary lymphomatous involvement of the salivary
glands, the parotid gland is involved in about 80%.
• In patients with Sjogren’s syndrome the prevalence of non-Hodgkin’s
lymphoma is about 44 times greater compared to control subjects,
therefore lymphoma has to be ruled out by imaging in this particular
patient population.

Undifferentiated Carcinoma
• Lymphoepithelial
• Eskimos: parotid, F > M,
familial
• Asian: submandibular,
M > F
• Large-cell
• Bimodal peaks
• M > F
• Parotid
• Small-cell
• 6th-7th decades
• M:F = 1.6:1
• parotid

Metastases
• Metastases to salivary glands are mainly observed in the parotid gland due
to the presence of intraglandular lymph nodes, which drain the face,
external ear, and scalp.
• Skin malignancies (melanoma, squamous cell carcinomas) are the most
common primary tumours metastasising to the salivary glands, therefore
careful clinical examination has to be performed.
• However, other malignancies, such as renal cell carcinomas, lung, breast
and gastrointestinal carcinomas can also metastasise to the parotid gland
or periparotid lymph nodes.

US image shows an oval, well-defined, homogeneous tumor with even margins (arrows) in
the right submandibular gland; the parenchyma of the gland (arrowheads) has been
changed by therapeutic neck irradiation. Despite its benign features, the tumor proved to
be a metastasis from a squamous cell carcinoma at the base of the tongue.

Power Doppler US image shows a metastasis (arrowheads) to the superficial lobe of the
parotid gland (arrows) from a melanoma. The tumor is lobulated, inhomogeneous, and
virtually anechoic with posterior acoustic enhancement and chaotic, mainly peripheral
vessel segments.

Represents a manifestation of autoimmune disease
in the salivary glands.
This benign entity may be difficult to distinguish
from malignant tumours due to
• its focal character
• contrast medium enhancement
• its irregular margins
The benign lymphoepithelial lesion (BLEL)
or Godwin’s tumour

Conclusions
• Hugely diverse histopathology
• Accurate pathologic diagnosis does influence
management
• Relatively rare malignancies
• Utilize preoperative studies when indicated

Imaging of salivary gland tumours

Imaging of salivary gland tumours

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