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salivary glands radiology. Definition of Salivary Gland Disease. Dental diagnosticians have responsibility for detecting disorders of the salivary glands A familiarity with salivary gland disorders and

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definition of salivary gland disease
Definition of Salivary Gland Disease
  • Dental diagnosticians have responsibility for detecting disorders of the salivary glands
  • A familiarity with salivary gland disorders and

applicable current imaging techniques is an essential element of the clinician ’ s armamentarium .

clinical signs and symptoms
Clinical Signs and Symptoms
  • Diseases of the major salivary glands may have single or multiple clinical features.
  • Pain and altered salivary flow may be present.
  • The periodicity and longevity of these symptoms are important in the differential diagnosis,
  • a review of the medical history and physical

condition of the patient may provide important information.

applied diagnostic imaging of the salivary glands
Applied Diagnostic Imagingof the Salivary Glands
  • Diagnostic imaging of salivary gland disease may be undertaken to differentiate inflammatory processes from neoplasticdisease .
  • diffuse disease from focal suppurative disease, identify and localize sialoliths, and demonstrate ductalmorphologyanddetermine the anatomic location of a tumor, in addition , differentiate benign from malignant tumor .
plain film radiography
PLAIN FILM RADIOGRAPHY
  • Plain film radiography is a fundamental part of the examination of the salivary glands and may provide sufficient information to preclude

the use of more sophisticated and expensive imaging techniques .

  • It has the potential to identify unrelated pathoses in the areas of the salivary glands that may be mistakenly identified as salivary gland disease, such as resorptive or osteoblastic changes in adjacent bone .
plain film radiography1
PLAIN FILM RADIOGRAPHY
  • Panoramic and conventional posteroanterior (PA) skull radiographs may demonstrate bony lesions, thus eliminating salivary pathosis from the differential diagnosis.
  • Unilateral or bilateral functional or congenital hypertrophy of the masseter muscle may clinically mimic a salivary tumor. A plain film extraoral radiograph may demonstrate a deep antegonialnotch, overdeveloped mandibular angle, and exostosison the outer surface of the angle in cases of masseter hypertrophy.
  • Plain film radiographs are useful when the clinical impression,

supported by a compatible history, suggests the presence of sialoliths

(stones or calculi).

intraoral radiography
INTRAORAL RADIOGRAPHY
  • Sialoliths in the anterior two thirds of the submandibular duct are typically imaged with a cross-sectional mandibularocclusalprojection
  • The posterior part of the duct is demonstrated with an over-the-shoulder occlusalprojection view, where the directing cone is placed on the shoulder and central

ray directed in an anterior direction through the angle of the mandible, with the patient ’ s head tilted to the unaffected side and rotated back .

  • Parotid sialoliths are more difficult to demonstrate than the submandibular variety as a result of the tortuous course of Stensenduct around the anterior border of the masseter and through the buccinator muscle. As a rule, only sialoliths anterior to the masseter muscle

can be imaged on an intraoral film.

slide11
Underexposed mandibularocclusal radiograph demonstrating radiopaquesialolith inWharton duct. Note the classic laminated appearance.
slide12

Periapical radiographs of the same case. Theradiopaque calculus can be localized lingual to the teeth by applying appropriate object localizationrules

extraoral radiography
EXTRAORAL RADIOGRAPHY
  • A panoramic projection frequently demonstrates sialoliths in the posterior duct or reveals intraglandularsialoliths in the submandibular gland.
  • The image of most parotid sialolithsis superimposed over the ramus and body of the mandible .
  • To demonstrate sialoliths in the submandibular

gland, the lateral projection is modified by opening the mouth, extending the chin, and depressing the tongue with the index finger.

extraoral radiography1
EXTRAORAL RADIOGRAPHY
  • Sialoliths in the distal portion of Stensen duct or in the parotid gland are difficult to demonstrate by intraoral or lateral extraoral views. However, a PA skull projection with the cheeks puffed out may move the image of the sialolith free of the bone .
slide18
Anteroposterior skull view with cheek blownout to provide air contrast to reveal a parotidsialolith(arrow).
conventional sialography
CONVENTIONAL SIALOGRAPHY
  • First performed in 1902, sialography is a radiographic technique where a radiopaque contrast agent is infused into the ductalsystem of a salivary gland before imaging with plain films, fluoroscopy, panoramic radiography, conventional tomography, or CT. Sialography remains the most detailed way to image the ductalsystem .
  • The parotid and submandibular glands are more readily studied with

this technique.

  • A survey or “ scout” film is usually made before the infusion of the

contrast solution into the ductalsystem .

  • With this technique, Lipid-soluble (e.g., Ethiodol) or non –Lipid-soluble (e.g., Sinografi n) contrast solution is then slowly infused

until the patient feels discomfort (usually between 0.2 and 1.5 ml).

conventional sialography1
CONVENTIONAL SIALOGRAPHY
  • These iodine-containing agents render the ductal system radiopaque, The image of the ductal system appears as “ tree limbs, ” with no area of the gland devoid of ducts. With acinarfilling, the “ tree ” comes into “ bloom, ” which is the typical appearance of the parenchymalopacification phase .
  • Non – lipid-soluble contrast agents are preferred because of reports of inflammatory reactions subsequent to inadvertent extravasation of lipid-soluble agents .
  • Sialographyis indicated for the evaluation of chronic inflammatory

diseases and ductalpathoses. Contraindications include acute

infection, known sensitivity to iodine-containing compounds, and

immediately anticipated thyroid function tests.

slide21

SialographyA, Lateral projection of the parotid demonstrating opacificationall the way to the terminal ducts and acini. B, Anteroposterior projection of the same gland demonstrating“ parenchymal blushing ” from acinaropacification.

slide22

Sialogram of Normal Submandibular Gland. This lateralview demonstrates parenchymal blushing. Normal fine branching isvisible. Lack of parenchymal blushing at the anteroinferior margin iscaused by radiographic burnout.

computed tomography
COMPUTED TOMOGRAPHY
  • CT is useful in evaluating structures in and adjacent to salivary glands; it displays both soft and hard tissues and minute differences in soft tissue densities .
  • CT is useful in assessing acute inflammatory processes and abscesses as well as cysts, mucoceles, and neoplasia. Calcifications such as sialoliths are also well depicted with CT.
slide24

CT Images with Soft Tissue Algorithm. A, Axial viewdemonstrating bilateral enlargement of the parotid glands (arrowheads).B, Coronal view of the same patient. The clinical/histopathologicdiagnosis was autoimmune parotitis.

magnetic resonance imaging
MAGNETIC RESONANCE IMAGING
  • MRI for soft tissue mass details and localization
  • Differanciates :
  • St vs. Ht
  • Normal vs. abnormal tissue
  • Identifies facial nerve ( parotid )
  • Containdications:
  • -pacemaker
  • -cochlear implant .
slide26

These magnetic resonance images reveal a lymphoepithelial cyst involving the rightparotid gland. This axial T1-weighted image reveals a well-defined circular lesion involving the rightparotid gland with an internal signal isointense to muscle, and the matching T2-weighted image

scintigraphy nuclear medicine positron emission computed tomography
SCINTIGRAPHY (NUCLEAR MEDICINE, POSITRONEMISSION COMPUTED TOMOGRAPHY)
  • Selective up take of techntium
  • Asseseessilvary gland function (not anatomy)
  • Expel technetium after stimulations
slide29

Scintigraphy. A, 99m Tc-pertechnetatescan of the salivary glands (right and left anterioroblique views) demonstrates increased uptake ofradioisotope in the right parotid gland (blackarrowhead). B, Scintigram taken after administrationof a sialogog (lemon juice) demonstratesretention of isotope in right parotid gland (whitearrowheads). This is a typical presentation of salivarystasis, Warthin tumor, or oncocytoma.

ultrasonography
ULTRASONOGRAPHY
  • For superficial , soft tissue swilling
  • Differentioates cystic vs. solid
  • Us-guide FNA
slide31

Ultrasonography (US) Image of Right Parotid Gland. Awell-delineated solid mass is suggested by echo returns within thelesion (arrows). US appearance is typical of a benign salivary tumor

obstructive and inflammatory disorders
Obstructive and inflammatory disorders
  • Sialolithiasis
  • Bacterial sialadenitis
  • Sialodochitis
  • Autoimmune sialadenitis
sialolithiasis
sialolithiasis

** calculus and salivary stones

** Formation of calcified obstruction within salivary gland duct

** Clinical features :

Chronic retrograde infection

Swelling and pain with eating

Major or minor S.G

Usually one S.G involved

Submandibular S.G >> 83% of the cases

slide35

**Raiographic features :

  • Radiopaque :

* Vary from cigar to oval or round shape

* Homogeneous radiopaque internal structure

  • Radiolucent : ductal filling defect

** sialography is helpful when obstruction is undetectable on plain RG .

** CT may also detect minimally calcified sialoliths not visible on plain films.

slide38

Sialography should not be performed if a radiopaque stone has been shown by plain radiography to be in the distal portion

of the duct

  • More than 90% of stones larger than 2 mm

are detected as echo-dense spots in US images

slide39

D/D:

phleboliths

dystrophic calcification of LN

palatine tonnsiliths

Tx:

  • sialogogs to stimulate saliva secretion.
  • Sialography may also stimulate discharge .
  • Surgical removal of the sialolith
  • Removal of the whole involved S.G
bacterial sialadentis
Bacterial sialadentis
  • Parotitis and sabmandibulitis
  • Acute or chronic bacterial infection of terminal acini or parenchyma of S.G
slide45

Acute bacterial infections

  • most commonly affect the parotid gland
  • Most cases are unilateral
  • may occur at any age

Clinical features :

  • swelling
  • redness
  • Tenderness
  • Malaise
  • Enlarged regional lymph nodes
  • suppuration may also be noted

Untreated acute suppurative infections typically form abscesses.

slide46

Chronic bacterial infection :

can affect any of major S.G

causing extensive swelling and culminating in

fibrosis

may be a consequence of un-Tx acute sialadenitis or some types of obstruction .

intermittent swelling, pain when eating,

and superimposed infection resulting from salivary stasis

slide47

RG features :

Sialography is contraindicated in acute infections

  • Epithelial flattening may lead to mildly dilated terminal ducts and saclike acini, which is demonstrable with sialography.
  • even distribution throughout the gland is seen

in recurrent parotitis and autoimmune disorders

US may distinguish between diffuse inflammation and suppuration

  • MRI is an appropriate alternative
  • examination in cases which sialography is contraindicated
slide48

Treatment

  • attention to oral hygiene
  • local massage
  • increased fluid intake
  • oral sialogogs (sour citrus fruit wedges or salivary stimulants).
  • antibiotic regimen may also be indicated.
  • surgical remedies ranging from partial to total

excision of the gland

sialodochitis
Sialodochitis
  • Ductalsialadenitis
  • inflammation of the ductal system of the salivary glands.
  • Clinical features :

** sialectasia or dilation of ductal system

** sausage-string appearance of the main

duct and its major branches

Tx : as tx of sialadenitis

slide51

Lateral view of a sialogram of a parotid gland demonstrating

a negative fill defect (arrow) representing a noncalcifiedsialolith

and prominent intermittent stricture and dilation of the main and secondary

ducts, which is typical of advanced sialodochitis.

autoimmune sialadenitis
Autoimmune Sialadenitis
  • Myoepithelialsialadenitis, Sjögren syndrome, benign lymphoepithelial Lesion Mikulicz disease , sicca syndrome, dacryosialoadenopathiaatrophicans, and autoimmune sialosis
  • group of disorders that affect the salivary glands and share an autosensitivity
slide54

Clinical features :

** range from recurrent painless swelling of

the salivary glands (usually the parotid gland) to a stage that includes enlargement of the lacrimal glands

** xerostomia and xerophthalmia

  • diagnosis can be made on the basis of any two of the following three features:

Dry mouth, dry eyes, and rheumatoid disease.

slide55

most common in adults (40- 60 year-old )

  • 90% to 95% female prevalence.
  • 44 times greater risk for development of non-Hodgkin lymphoma
slide56

RG features :

  • early stages :

** punctate and globular spheric collection

of contrast agent throughout the G >>>> sialectases

**main duct may appear normal, but the intraglandular ducts may be narrowed or not even evident

  • As the disease progresses :

** the collections of contrast agent increase in size and are irregular in shape >> cavitarysialectases

** larger cavities of contrast agent and dilation of

the main ductal system may also be present

**Cavitation and glandular fibrosis are the result of recurrent

inflammation

  • At the end point of this disorder, complete destruction of the gland occurs
slide57

D/D :

  • chronic bacterial OR granulomatous infections
  • multiple parotid cysts associated with (HIV) infection.
conventional sialography of left parotid
Conventional Sialography of Left Parotid.

Lateral projection demonstrates punctatesialectases distribute throughout the gland, which is suggestive of autoimmune sialadenitis. Clinical/histopathologic diagnosis was Sjögren syndrome

Anteroposterior projection of

the same gland.

sialography of the left parotid
Sialography of the Left Parotid.

Punctate (small spheric), globular (larger spheric), and cavitary (larger, irregular) sialectases with some dilation of the main duct are suggestive of advanced autoimmune disease with parenchymal destruction with retrograde infection in lateral (A) and anteroposterior (B) projections. Clinical/histopathologic diagnosis was Sjögren syndrome

slide60

Tx :

Relief of symptoms.

  • Underlying systemic rheumatoid conditions are typically treated with anti-inflammatory agents, corticosteroids, and immunosuppressive therapeutic agents .
  • Salivary stimulants
  • increased fluid intake
  • artificial saliva and tears
  • surgically by local or
  • total excision of the symptomatic gland.
non inflammatory disorders
Non-inflammatory disorders

1- Sialadenosis

2- Cystic Lesions

3- Benign tumers : Benign Mixed Tumor

Warthin Tumor

Hemangioma

4- malignant tumers :

Mucoepidermoid Carcinoma

Malignant Mixed Tumor

sialadenosis
Sialadenosis
  • Sialosis
  • nonneoplastic, noninflammatory enlargement of primarily the parotid salivary glands
  • usually related to metabolic and secretory disorders of the parenchyma associated with diseases of nearly all the endocrine glands , protein deficiencies, malnutrition in alcoholics ,

vitamin deficiencies, and neurologic disorders

slide63

Enlarged affected glands

  • RG features :

sialography>> may show enlarged (splayed duct) or normal S.G

CT and MRI>> provide a more straightforward depiction of the glands but

are nonspecific and require correlation with the clinical findings and history.

slide64

Tx :

  • identifying the cause of the metabolic or secretory disorder
  • Conservative tx : local massage

increased fluid intake

oral sialogogs

sialadenosis1
Sialadenosis

 34-year-old female with hypothyroidism. (a) Digital sialogram right parotid gland shows attenuated main duct and the intraparenchymal branches. (b) Axial T2 weighted image demonstrates symmetrically enlarged parotid glands without any focal lesion

cystic lesion
Cystic lesion:

cysts of the salivary gland are rare (less than 5% of all salivary gland mass)

-most commonly occure unilaterally in parotid gland

-they may be congenital(branchial),lymphoepithelial,dermoid or acqurid including mucous retention cysts

-may be intraglandular or extraglandular

cystic neoplasm
Cystic neoplasm-
  • Mucous extravationpseudo cysts : lack epithelial lining and result from ductal rupture
  • Ranulas: are retention cysts usully occure as result of obstruction sublingual duct
  • Benign lymphoepithelial cysts: sequelae of cystic degeneration of salivary inclusion within lymph nodes
  • Multicentric parotid cysts associated with HIV
radiographic features
Radiographic features:
  • cystic lesion typically appear as well-circumscribed ,nonenhancing(with contrast)
  • low density areas when examined on CT
  • appear as well-circumscribed,high-signal areas on 2T-weighted MRI
slide69
Cont…
  • when imaged with us,cysts are sharply marginated and echo free as dark area
  • treatment : typically surgical , involving local or total excision of the gland
benign tumors
benign tumors
  • -relatively uncommon
  • -occur in less than 0.003% of the population
  • -3% of all tumors
  • -80% of salivary tumors arise in the parotid
  • -5% in the submandibular
  • -1% sublingual
  • -10%-15% minor salivary gland
  • -most are bengine or low-grade malignancies
  • -high-grade malignancies are uncommon
slide71
Cont…
  • the chance of neoplasm of major salivary glands being directly with the size of the gland
  • Radiographic features:
  • -Benign tumors and low-grade malignancies may have a similar appearance
  • -well-defined margins, which are most apparent on CT or MRI examinations
  • -tumor to appear more radiopaque because the vascularity of the tumor is greater than that of the adjacent salivary gland tissue
slide72
cont
  • -benign masses are typically less echogenic than parenchyma, sharply defined, and of essentially homogeneous echo strength and density
  • -Sialography may suggest a space occupying mass when the ducts are compressed or smoothly displaced around the lesion (the “ ball-in-hand ” appearance)
treatment
Treatment
  • typically surgical
  • the parotid gland may be either partially or totally excised
  • submandibular and sublingual glands are in variably totally excised
benign mixed tumor
Benign mixed tumor
  • Pleomorphic adenoma
  • a neoplasm arising from the ductal epithelium of major and minor salivary glands exhibiting epithelial and mesenchymal components.
  • The benign mixed tumor accounts for 75% of all salivary gland tumors
  • typically occurs in the fifth decade of life as a slow-growing, unilateral, encapsulated, asymptomatic mass
  • A slight female predilection exists
  • Recurrence occurs in 50% of cases after excision
  • Malignant transformation is reported in up to 15% of untreated cases
radiographic feature
Radiographic feature:
  • sharply circumscribed in frequently lobulated and essentially round homogeneous lesion that has a higher density than the adjacent glandular tissue
  • Calcifications within the tumor are commonly seen and are well depicted on CT
  • This tumor has various tissue signals in different MRI techniques
  • Foci of low signal intensity (dark areas) usually represent areas of fibrosis or dystrophic calcifications
  • If a calcification is present (signal void) the diagnosis favors a benign mixed tumor
slide76

CT and MRI Images of a( Pleomorphic Adenoma)

  • In the T2-weighted image, note the increased signal of the tumor, which is now hyperintense to muscle.
slide77
cont
  • In the axial MRI T1-weighted image, the tissue signal of the tumor is isointense with muscle
slide78
cont
  • In the axial CT soft tissue algorithm image, note the well-defined periphery (black arrows).
  • the internal density that is less than surrounding muscles. The remaining parotid gland (white arrow) is displaced laterally
warthin tumor
Warthin tumor:
  • Papillary cystadenoma lymphomatosum, adenolymphoma, and lymphomatous adenoma
  • benign tumor arising from proliferating salivary ducts trapped in lymph nodes during embryogenesis of the salivary gland
clinical features
Clinical features
  • the second most common benign neoplasm of the salivary glands
  • accounting for 2% to 6% of the parotid tumor
  • slow-growing, painless, round-to-ovoid mass
  • In 20% of cases the tumors are multiple
  • Typically afflicts males older than 40 years and may be unilateral or bilateral
radiographic features1
Radiographic features:
  • CT and MRI are the preferred techniques
  • not specific and istypical of benign salivary tumors
  • On CT, this tumor may be of either soft tissue or cystic density
  • On MRI, it is heterogeneous and may demonstrate hemorrhagic foci
  • characteristically intensely hot on 99m Tcpertechnetate scans
  • The US presentation of Warthin tumor is that of a solid mass (anechoic), if the massis not cystic
slide82
CONT…
  • An axial soft tissue algorithm CT image of a case of bilateral
  • Warthin tumor, a large tumor involving the left parotid (white arrow) and a much smaller tumor on the right side (black arrow)
hemangioma
Hemangioma:
  • Vascular nevus
  • a benign neoplasm of proliferating endothelial cells (congenital hemangioma) and vascular malformations, including lesions resulting from abnormal vessel morphogenesis
clinical features1
Clinical features:
  • the most frequently occurring nonepithelial salivary neoplasm, accounting for 50% of the cases
  • 85% arise in the parotid gland
  • the most common salivary gland tumor during infancy and childhood
  • The average age at diagnosis is 10 years.
  • occurring in the first two decades of life 65%
  • They are frequently unilateral and asymptomatic
  • A 2:1 female-to-male predilection exists
treatment1
Treatment:
  • by local excision for those who do not undergo spontaneous remission
radiographic features2
radiographic features:
  • Phleboliths are common
  • They appear as discrete soft tissue calcifications with a radiolucent center
  • best identified on plain films and CT
  • The CT presentation of hemangioma is a soft tissue mass that is well distinguished from surrounding tissue
  • On MRI the tumor has a signal similar to that of adjacent muscle onT1-weighted images and a very high signal on T2-weighted images
  • US usually demonstrates well-defined margins in the hemangioma
  • Phleboliths image as multiple hyperechoic areas within the body of the gland itself
malignant tumor
Malignant tumor:
  • About 20% of tumors in the parotid are malignant
  • 50% to 60% of submandibular tumors
  • 90% of sublingual tumors
  • 60% to 75% of minor salivary gland tumors
radiographic features3
Radiographic features:
  • variable and is related to the grade, aggressiveness, location, and type of tumor
  • ill-defined margins, invasion of adjacent soft tissues (such as fats paces), and destruction of adjacent osseous structures are considered to be typical indicators of malignancy
treatment2
Treatment:
  • typically surgical
  • Low-grade malignant tumors of the parotid gland may be either partially or totally excised
  • Submandibular and sublingual glands are invariably totally excised
  • High-grade tumors may require radical neck dissection
  • Combinations of surgery, the rapeutic radiation, and chemotherapy may also be used
mucoepidermoid carcinoma
Mucoepidermoid Carcinoma:
  • a malignant tumor composed of a variable admixture of epidermoid and mucous cells arising from the ductal epithelium of the salivary glands
clinical features2
Clinical features :
  • the most common malignant salivary gland tumor (35%) most commonly the parotid gland.
  • the rest are found in the minor glands, with the palate
  • being the most frequent location
  • A wide age range exists, with the highest prevalence in the fifth decade of life
  • A slight predilection for females exists
  • The low-grade variety rarely metastasizes
  • movable, slowly growing, painless nodule
  • It is usually only 1 to 4 cm in diameter
  • The prognosis is good; the 5-year survival rate is greater than 95%
slide92
CONT….
  • high-grade tumors often cause facial pain and paralysis, have ill-defined margins and are relatively immobile
  • Metastasis by blood and lymph are common
  • with recurrence in half the patients after excision
  • The prognosis is poor and varies with the histologic grade; the 5-year survival rate may be as low as 25%
radiographic features4
Radiographic features:
  • low-grade mucoepidermoid carcinoma may present a lobulated or irregularly sharply circumscribed appearance on contrast enhanced CT or MRI
  • Cystic are a may present and, rarely, calcifications may be seen
  • high-grade mucoepidermoidcarcinom atypically relies on the appearance of irregular margins and ill-defined form when the mass is examined with CT or MRI
  • In CT images, the tumor as an irregular homogeneous mass, slightly denser than the gland parenchyma
slide94
CONT …..
  • high-grade mucoepidermoid carcinoma has homogeneous low signal intensity (dark) on T1-weighted images, but T2-weighted images are more heterogeneous and intense(brighter) than T1-weighted images but still slightly darker (low signal) relative to the surrounding tissues
  • Cavitary sialectasia and ductal displacement may be noted on sialographic images of this tumor
malignant mixed tumor
Malignant Mixed Tumor:
  • Carcinoma ex mixed tumor, carcinoma ex pleomorphic adenoma and malignant pleomorphic adenoma
  • composed of three distinct types of tumors
  • The most common is carcinoma ex mixed tumor which arises from the epithelial components of a preexisting benign mixed tumor
slide96
CONT ….
  • The other two, which are extremely rare :
  • 1-true malignant mixed tumor (from both epithelial and mesenchymal components of a mixed tumor)
  • 2-the metastasizing mixed tumor, which appears histologically benign but behaves in a malignant fashion
slide97

These four axial CT and magnetic resonance images depict an adenoid cystic carcinoma of the right submandibular gland. Note

  • the well-defined periphery, making it difficult to differentiate from a benign tumor The internal density of the tumor in this soft tissue algorithm
  • CT image is almost equal to the remaining gland
slide98
CONT…..
  • The tissue signal in this T1-weighted magnetic resonance image is very slightly less than the remaining gland
slide99

a T2-weighted magnetic resonance image, the high signal of the tumor contrasts with the remaining gland

slide100

CONT….

  • a T1-weighted postgadolinium, fat-saturation image, the tumor has a higher signal than in the remaining gland
clinical features3
Clinical features:
  • typically begins as a slowly growing mass that suddenly undergoes rapid proliferation
  • often accompanied by pain and facial paralysis
  • Metastasis is early and the prognosis is unfavorable
radiographic features5
Radiographic features:
  • The presentation of this tumor is similar to that of the high-grade mucoepidermoid carcinoma
  • MRI is usually superior to CT for tumor definition
other malignant and metastatic tumors
OTHER MALIGNANT AND METASTATIC TUMORS
  • Although the incidence of other malignant tumors of the major salivary glands is low, a significant variety exists in their histogenesis
  • Of all malignant salivary gland tumors, 23% are adenoid cystic carcinomas
  • the majority of these neoplasms develop in the minor salivary glands
  • Adenocarcinoma accounts for 6.4% of all salivary gland malignancies
  • with acinic cell carcinoma, primary lymphoma, and squamous cell carcinoma occurring with even less frequency
slide104
CONT….
  • cell carcinoma occurring with even less frequency
  • Pain, paresthesia and even paralysis may be present, especially in high-grade tumors
  • Tumor spread may be by direct invasion or metastasis
  • Metastasis of tumors of the salivary glands is not unusual
  • Metastatic lesions in the parotid gland are more common
  • Most metastatic lesions of the parotid gland occur through the lymphatic system and include squamous cell carcinoma, lymphoma, and melanoma
  • metastasis from the lung, breast, kidney, and gastrointestinal tract has been reported
radiographic features6
Radiographic features:
  • nonspecific and similar to that of the high-grade mucoepidermoid carcinoma
  • US may demonstrate echo-free cystic areas in adenoid cystic carcinomas.
slide106
CONT ….
  • This axial soft tissue algorithm CT image reveals an adenocarcinoma of the left parotid gland.
  • Almost all the gland has been replaced by this ill-defined tumor that has some peripheral enhancement .
  • and lower density internal structure, likely representing necrotic regions
slide107
CONT….
  • Ultrasonography. The mass in the submandibular gland(arrows) demonstrates a heterogeneous hypoechoic pattern compared with the adjacent tissue.
  • The histopathologic diagnosis was adenoid cystic carcinoma
slide108
CONT….
  • Contrast-enhanced axial soft tissue algorithm CT image
  • demonstrating a mass in right parotid gland with a poorly marginated.
  • heterogeneous, slightly lobulated appearance (white arrows).
  • Poorly defined margins suggest a low-grade malignancy rather than benign tumor , although the CT appearance of both is similar .
  • Histopathologic diagnosis was low-grade mucoepidermoid carcinoma