Ultrasound of the Salivary Glands - HD

Introduction

Hi, my name is Diana Gini.
I'm from RBA Medical Center
and the faculty of Medicine, Technion, Haifa, Israel,
and my lecture will be on ultrasound of the salivary glands.

Learning Points

These are the learning points, indications for ultrasound,
examination, ultrasound, technique, normal anatomy,
inflammation, tumors, miscellaneous, and new technologies.

Indications for Ultrasound

The indications for ultrasound
of the salivary glands are lump in the gland
or the neck pain, mouth, dryness
and abnormality on previous x-rays, CT or sialogram,
and use it for guidance of injection, aspiration or biopsy.

Ultrasound Technique

The technique of the examination,
we use a high frequency five
to 12 megahertz wideband, linear array transducer
for the parotid gland.
The planes are axial, placing the probe
inferior to the ear and coronal placing it
anterior to the ear.
For the submandibular gland, we perform sagittal
and coronal planes while the probe is in the submandibular
position and for the sublingual glands,
the coronal plane is used while the probe is in the
submental position.

Normal Anatomy

This we have the normal anatomy of the three main glands,
parotid glands, the submandibular gland
and anteriorly to it, the sublingual glands.
The parotid gland is located in a triangle bounded
by the tip of the mastoid, the zygomatic arch, arch
and the angle of the mandible.
And these are the planes that we examine.
The parotid gland, the Stensen duct
that is the atory duct is opening at the level
of the second molar.
This is a normal examination of the parotid gland.
Here we see the line of the mandible
and the line of the tip of the mastoid.
The master masseter.
The gland is made by fatty glandular tissue,
lymphoid tissue vessels, nerves, and lymph nodes.
It has an elliptical shape, it's homogeneously echogenic
and is divided into two lobes by the facial nerve
because it is not seen on ultrasound, we use
the retromandibular vein that is very well seen
on color doppler and
besides the vein,
the facial nerve is placed.
We also see some branches
of the external carotid artery together with the vein.
And this is the plane that divides the superficial lobe
from the deep lobe.
Here we have other examples
of a normal gland on the right side and on color.
Doppler perfectly seen the veins
and the branches of the external carotid artery.
And this is on the left side.
The normal submandibular gland is placed medial to the body
of the mandible
and superficial to the anterior belly of the digastric
and mylohyoid muscles.
It's also made by fatty glandular tissue
and the duct that is draining is the Wharton's duct.
The normal sublingual glands are very small, sometimes
only seen in the presence of pathology and is
placed under the tongue anteriorly
to the submandibular glands.
Out of the main salivary glands,
we have many minor salivary glands, about 600
to a thousand that are located throughout the base,
paranasal sinuses, nasal cavity, oral mucosa,
hard and soft palate, pharynx and larynx.
Each one of these glands is the discrete unit
with its own duct that is opening into the oral cavity.

Inflammation

The main pathologies of the salivary glands is inflammation.

Acute Sialadenitis

Acute sialadenitis, it is usually viral
mumps or cytomegalovirus,
but maybe bacterial in infants,
especially staphylococcus maybe uni or bilateral.
And it appears like a diffuse enlargement of the gland
that has a irregular hyperechogenicity.
On color doppler the blood flow is increased.
We may see also lymphadenitis into the gland or in the neck,
and in some cases we may see a focal abscess
that is drained.
Under ultrasound guidance.
Here we have examples of acute sialadenitis in children.
In this one we have a bilateral enlargement
and hyperechogenicity of the parotid glands is a case of mumps.
In this child, we see an enlargement
of the submandibular gland,
and this is a stone that is very nicely seen into the collecting duct.
Also, we saw a lymph node that was,
rather enlarged
but conserving the normal anatomy
and was lymphadenitis.
This is a very homogeneous gland, parotid gland,
a submandibular gland with,
some hypoechoic foci.
And on color doppler we see a very
rich vascularization.
In these two examples of parotitis in adults,
we see the enlargement
and hyperechogenicity very,
inhomogeneous on ct, we saw a very,
small stone in this case that was missed on ultrasound,
this is a case of a submandibular gland abscess.
We may see it also on ct.
We have, liquefaction, hypo
or echoic area in the submandibular gland
and the hypoechoic area
remaining is very vascularized.
And this is another case of an abscess
in the submandibular gland compared
to the normal contralateral site.

Chronic Sialadenitis

Chronic sialadenitis is usually associated with ectasia.
The gland is normal sized or smaller than the normal gland.
Hypoechoic inhomogeneous has round hypo
echoic areas and small scattered punctate echo
echogenic densities.
Usually the blood flow is not increased.
What are the differential diagnosis, sarcoidosis
and other granulomatous diseases.
Sjogren syndrome, disseminated lymphoma,
hematogenous metastasis, and benign lymphoepithelial lesions.
In HIV positive, these are two cases
of chronic lymphoepithelial sialadenitis where we see,
case of
bilateral chronic sialadenitis where this may be,
enlarged lymph nodes
or focal hyperechoic nodules.
We see also this hyperechoic punctate
inside the gland.
And in this case the collecting duct is very enlarged
with debris inside
and we demonstrated a very big, very,
large, stone inside the duct.

Sialolithiasis

Sialolithiasis is mostly seen in the submandibular glands.
Most of them calcified
and it leads to intermittent unilateral diffuse swelling.
Ultrasound is very good for the detection of stones
that appear like strongly hyperechoic lines
or points with visible acoustic shadowing
and related excretory ducts.
Ranula is a cystic mass due to duct obstruction.
Here we have an example of chronic sialadenitis.
The gland is not enlarged, is rather hypoechoic
and we see very well a stone in this very
dilated duct.

Sjogren Syndrome

Sjogren syndrome is a chronic autoimmune disease
with intense lymphocytic and plasma cell infiltration
and it leads to destruction of the salivary
and lacrimal glands.
We may see a,
small well-defined hypo
or anechoic areas
if the blood flow in this case will be increased.
And monitoring by ultrasound is required due
to its association with lymphoma
and biopsy recommended for fast growing
or more than two centimeter lesions.
Here we have a case of Sjogren syndrome.
We have a bilateral enlargement
and multiple hypoechoic foci
into the salivary glands on color doppler.
It is very vascularized and we performed a biopsy, a core biopsy
because we suspected that a lymphoma was
developed and really the core biopsy led to mild lymphoma.

Tumors

Tumors are very unusual
in the salivary glands.
They are only 1% of head and neck tumors.
Most of them are in the parotid glands
and most of these tumors are benign.
Those in the submandibular gland, that few tumors
just 50% are benign
and interesting in the sublingual glands, almost most
of them are malignant tumors may develop also in the minor
salivary glands, there are of two types.
The benign tumors are pleomorphic adenoma and Warthin tumors.
The malignant tumors are mucoepidermoid carcinoma, most
of them and in a less amount undifferentiated
carcinoma, lymphoma, sarcoma and metastasis.
In children, 65% of the tumors are benign,
mostly hemangio and pleomorphic adenoma,
but 35% are malignant
and the most common is mucoepidermoid carcinoma.
FNA for cytology is the preferred method for diagnosis.

Pleomorphic Adenoma

Pleomorphic adenoma, 90% are in the parotid gland
and are benign, but this, this tumor has a 15
to 20% rate of recurrence
and also may undergo malignant change.
It rarely invades and develops metastasis
and it appears like a hypoechoic, well-defined
ovalated margin tumor that may contain calcifications.
And on color doppler, it is hypovascular.
Here we have examples of pleomorphic adenoma.
This is a very,
rounded well delimited tumor hypoechoic
and on color doppler it is poorly vascularized.
In this tumor we see that the borders are very well defined,
but they are lobulated.
And this is a case of a pleomorphic adenoma that was
operated 25 years ago
and the patient came back with bilateral
multiple tumors and they were on FNA that we performed here.
Pleomorphic adenomas.
These are two cases in the submandibular glands tumors
that are unusual.
Here we have a case of pleomorphic adenoma
that is very vascularized,
so could be also a malignant pleomorphic adenoma.
And this very hypoechoic very well limited tumor
was on FNA and mesenchymal tumor.
Most probably schwannoma Warthin tumors are
2 to 12%
of the benign tumors associated with smoking.
It's hypoechoic,
well defined oval may contain anechoic areas
and opposite to pleomorphic adenoma.
It is hypervascular.
Here we have an example of a smoking patient that came
with bilateral tumors in the, parotid glands.
We see that we have in these tumors some areas
that are cystic.
It is hyperechoic but very irregular.
Inside
and on color doppler, we see that this vascularized and we performed,
FNA of this tumor
that confirmed the diagnosis of Warthin tumor.

Malignant Tumors

Mucoepidermoid carcinoma,
the cystic carcinoma are the most common malignant tumors.
They appear like hypoechoic inhomogeneous
and with borders that are irregular and ill-defined.
The vascularization is variable
and may be identical to benign tumors.
Other type of malignant tumors are lymphoma or metastasis.
Here we have a case of, mucoepidermoid carcinoma.
We see a very irregular tumor.
The borders are not well defined
and is, very hypoechoic.
Inhomogeneous, has a vascularization on color doppler.
It was operated two years ago
and came back with lymphadenopathy on the one
to three compartments of the neck.
Here we see a lymph node that is very enlarged around it
and hypoechoic.
We performed FNA of this nodule
and other nodules that we saw,
and both of them were recurrent mucoepidermoid carcinoma.
This is a case of malignant lymphoma for the parotid gland.
We see the,
net structure of the, gland
that is enlarged very hypoechoic.
In this case, we performed a core biopsy that,
demonstrated the lymphoma on pet ct.
We see a high uptake in the parotid glands
and were also, uptakes in the pelvis.
This is another example
of a follicular lymphoma in the submandibular gland
with large hypoechoic masses.

Miscellaneous Lesions

Miscellaneous lesions, cysts, some of the cysts
of the parotid gland are derived from the branchial clefts
or branchial pouches.
Some are mucus retention cysts.
This, for example, is an example
of mucus retention cyst.
We see a very, anechoic lesion with,
some mucus inside.
We performed an FNA and aspiration that confirmed.
Mucus retention cyst. This is the CT of the patient.

Sialosis

Sialosis is a non-inflammatory non-neoplastic recurrent gland
swelling, usually bilateral
and associated with endocrine diseases.
Malnutrition, hepatic cirrhosis, chronic alcohol
or different deficiency disease, mostly sialosis.
The glands are enlarged hyperechoic
and without focal lesions or increased blood flow.

Trauma

We may see trauma of the salivary glands.
They are most often in the parotid gland
and may cause hematoma or even sialocele
and damage to facial nerve and Stensen duct.
This is a case of a young man with a blunt
trauma to the face.
And here we see a large hematoma in the parotid gland.

New Technologies

Elastography

What about new technologies?
Elastography is a technology that may demonstrate
the consistency, the characteristics of the tumors.
But we see that in this case, for example,
between this pleomorphic adenoma
and this squamous cell carcinoma,
the elastography was not very different,
so the results were not consistent.
And this is a limited
technique in the differential diagnosis between benign
and malignant salivary glands, masses.
Shear wave elastography is also feasible technique
for salivary glands lesions,
but elastography artifacts aggravated
by the regional anatomy may hinder this technique
and overlapping indices for malignant
and benign lesions limit its utility
and really a lobulated margin proved
to be the only significant criterion on the B-mode ultrasound
capable of differentiating between malignant
and benign tumors.
Neither the internal structure nor the vascularization
or sonographic features can identify pathology for certain
and could not be used for differentiating
between benign and malignant tumors.

Contrast-Enhanced Ultrasound

What about contrast enhanced ultrasound?
Pleomorphic adenomas are hypovascularized
with a poor perfusion Warthin tumors
and malignant tumors are hypervascularized
with a rich perfusion.
The malignant tumors show significantly shortened time
to peak and richer maximum signal intensity compared
with Warthin tumors.
So these features of salivary gland masses identified
with CEUS may be helpful in the differential diagnosis
of salivary gland masses.
Regarding perfusion, that was analyzed.
There is a difference in perfusion between benign and malignant
salivary glands that is significant
and this new method seem to improve the validity of CEUS
in, differentiating between masses.

Limitations of Salivary Gland Ultrasound

What are the limitations of salivary gland ultrasound?
The location of the lesion.
Those lesions that are located penetrating the deep lobe
of the parotid gland
or behind the acoustic shadow
of the mandible may be difficult to
demonstrate on ultrasound.
Also, malignant tumors infiltrating bones, skull base
or parapharyngeal space are difficult to identify
and sometimes hyperechoic bubbles of air mixed with saliva may mimic stones in the Wharton's duct.

Conclusion

In conclusion, ultrasound is a valuable
and useful method for the diagnosis
of salivary gland diseases.
The nature of underlying disease may be suggested on
the basis of ultrasound findings
and ultrasound enables FNA
and core biopsy guidance of lesions.
Thank you for your attention.