Radiographic Interpretation of Salivary Gland Diseases

Presented by : Mamta Shrestha Roll no:39 BDS IV th year

ContentsImage interpretation of salivary gland disorder 1) Obstruction and inflammatory disorder - Sialolithiasis - Bacterial Sialadenitis - Sialodochitis - Autoimmune Sialadenitis2) Non-inflammatory Disorders - Sialadenosis - Cystic lesions 3) Benign tumors - Pleomorphic tumor - Warthin’s tumor - Hemangioma

4) Malignant tumor - Mucoepidermoid CarcinomaSummary Conclusion References

Image interpretation of salivary gland disorders

1) Obstructive and inflammatory disorders

SialolithiasisSynonyms: calculus and salivary stones.

Disease mechanism: formation of a calcified obstruction within

salivary duct. Submandibular gland and Wharton's duct

are frequently affected.

Clinical features

Imaging Features• May appear as either radiopaque or radiolucent.

• Mucous plugs

• Vary in shape from long cigar shape to oval or round.

• When visible, they usually have homogeneous radiopaque internal structures.

• Sialography is helpful especially if sialoliths are radiolucent.

• The contrast agent usually flows around the sialoliths, filling the duct proximal to the obstruction .

• The contrast agent that flows around the sialolith is more radiopaque and may obscure small sialoliths.

Sialography should not be performed if a radiopaque stone is present in distal portion of duct because the procedure may displace in proximally into the ductal system, complicating subsequent removal.

• MDCT imaging detect minimally calcified sialoliths not visible on projection or plain images.

• Sialoliths must be differentiated from phleboliths and dystrophic calcification of lymphnodes.

• Phleboliths typically have radiolucent centre.

• Calcified lymph node usually appear

CAULIFLOWER

Treatment Encouragement of spontaneous discharge

through use of sialagogues to stimulate secretion.If discharge does not occur, the sialolith may be

removed by surgery, by more conservative method “basket “ retrieval method.

Last resort by total excision of involved salivary gland.

Bacterial Sialadenitis • Synonyms: Parotitis and

Submandibilitis

• Disease mechanism: Acute or chronic bacterial infection of the terminal acini or parenchymal of salivary gland.

• Chronic inflammation consequence untreated acute sialadenitis or associated with obstruction resulting from sialolithiasis, noncalcified organic debris, or stricture(scar or fibrosis) formation in excretory ducts.

Common affect parotid gland, submandibular gland.

These infection are the result of reduced salivary secretion and retrograde infection by oral flora .

Acute bacterial infection

• Chronic inflammation may effect any of the major salivary glands, causing extensive swelling and culminating fibrosis.

• Parotid is most often involved.

Clinical features

• Unilateral and occur at any age.

Swelling

Redness

Tenderness

Malaise

Acute cases

Enlarged regional lymph nodes and suppuration .

Untreated acute suppurative infection typically form abscesses.

Diagnosis clinical observation, systemic symptoms,and the expression of pus from the duct.

Chronic cases

Intermittent swelling

Pain when eating

Superimposed infection

resulting from salivary stasis.

Imaging features• Sialography is appropriate for use in cases of

suspected chronic infection.• Contraindicated acute infection

disrupted ductal epithelium may allow extravasation of contrast agent , resulting in a foreign body reaction and severe pain.

• Epithelial flattening may lead to mildly terminal ducts and saclike acini with sialography.

• The saclike acinar areas are referred to as sialectasia.• If connected to ductal system, abscess cavities may

fill with contrast media sialography .

• MRI appropriate alternative examination in cases in which sialography is contraindicated or not technically possible.

• Inflamed glands are usually enlarged and demonstrate a lower tissue signal on T1-weighted images and demonstrate a higher signal on T2- weighted images compared with the surrounding muscle .

Treatment

• Begins conservatively with attention to oral hygiene, local massage, increased fluid intake and use of oral sialagogues(sour citrus fruit wedges or salivary stimulants).

• Antibiotic regimen • If symptoms continue surgical remedies

partial to total excision of the gland .

SialodochitisSynonym: ductal sialadenitis.

Disease mechanism: -Is an inflammation of ductal system of salivary glands.

- Dilation of the involved system - In chronic cases interstitial fibrosis may also develop causing constriction of small segment of dilated duct. - common in both the submandibular and parotid glands

Imaging featureso Sialectasia or dilation of ductal system

prominent manifestation sialodochitis on sialography.

o If interstitial fibrosis develops “ sausage-string” appearance of main duct and its major branches produced by alternating strictures and dilations.

Treatment• Oral hygiene , local massage, increased fluid

intake and use of oral sialagogues.

• An appropriate antibiotic regimen.

• If symptoms continue, surgical remedies ranging from partial to total excision of the gland .

Autoimmune Sialadenitis• Synonyms: Myoepithelial sialadenitis,

Sjogren syndrome, benign lymphoepithelial lesion, sicca syndrome, autoimmune sialosis.

• Disease mechanism: Represents a group of disorders that affect salivary glands and share an autosensitivity.

Clinical features• Recurrent painless swelling of salivary gland

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

• Xerostomia and exophthalmia (primary Sjogren syndrome)

• Connective tissue disease, such as rheumatoid arthritis, progressive systemic sclerosis, systemic lupus erythematous or polymyositis (secondary Sjogren syndrome).

Diagnosis

Dry mouth Dry eyes Rheumatoid disease

Imaging features• In early stages of disease , the initiation of

punctate (<1mm) and globular (1to 2mm) spherical collections of contrast agent evenly distributed throughout the glands. ( Sialectases)

• Cavitation and glandular fibrosis are results of recurrent inflammation.

• Cherry blossom or branch less fruit laden tree .

Treatment plan Directed towards relief of symptoms.Underlying systemic rheumatoid conditions are

typically treated with anti-inflammatory agents, corticosteroids and immunosuppressive therapeutic agents.

Salivary stimulus, increased fluid intake, artificial saliva and tears are symptomatic treatment regimens for the eyes and mouth.

Advanced inflammatory changes may be treated surgically by local incision or totally excision of symptomatic gland.

Non-inflammatory disorders

SialadenosisSynonym: Sialosis

Disease mechanism:

nonneoplastic,noninflammatory enlargement of parotid salivary glands.

Usually related to metabolic and secretory disorders of parenchyma .

Imaging features

• Enlarged glands ,the ducts splayed.

Identifying the cause of metabolic or secretory disorder.

Conservative treatment, including local massage, increased fluid intake and use of oral sialagogues (sour citrus fruit wedges or salivary stimulants).

Treatment plan

Cystic lesions

Clinical features RareCommonly occur unilaterally in the parotid gland.May be congenital(branchial),lymphoepithelial,

dermoid,or acquired, including mucous retention cysts.

May be intraglandular or extra glandular in nature.

Cystic lesion

Imaging Features Cyst masses may be indirectly visualized on

sialography only by the displacement of the ducts arching around them.

MDCT imaging : cystic lesions typically appear as well-circumscribed, non-enhancing.

Cyst appear as well-circumscribed, high signal area on T2-weighted MRI.

When imaged with US, cyst are sharply marginated and echo-free(represented as dark area).

Treatment• Typically surgical, involving local or total excision

of the gland .

Benign tumors

Clin

ical

featu

res

• Uncommon, occurring in less than 0.003% of population.

• Approximately 80% of salivary tumors arise the parotid gland, 5% rise in the submandibular gland , 1% arise in the sublingual, and 10% to 15% arise in the minor salivary glands.

Benign Tumors

• Space- occupying mass when the ducts are compressed or smoothly displaced around the lesion ( the “ball-in-hand” appearance).

Sialography

IMAGING FEATURES

o Intravenous contrast enhancement MDCT examination .

o Contrast enhancement causes tumour to appear more radiopaque vascularity of the tumour is greater than that of adjacent salivary gland tissue.

benign masses are less echogenic than parenchyma ,sharply defined and of homogenous echo strength and density.

Ultrasonograhy

• ON MRI - benign tumours present as low-intensity(dark) or high-intensity (light) tissue, although the relative intensity of signal may indicate the presence of lipid, vascular or fibrous tissues.

Pleomorphic Adenoma

Synonym

• Benign Mixed Tumor

Disease

Mechanism

• Is a neoplasm arising from the ductal epithelium of major and minor salivary glands exhibiting epithelial and mesenchymal components.

On MDCT- sharply circumscribed, infrequently lobulated and round homogenous lesion.

Calcification within tumor are commonly seen and are well depicted .

Imaging Features

MRI

Relatively low (dark) in T1-

weighted images

Intermediate on proton density –weighted images

Homogenous high intensity (bright) on T2-

weighted images

Various tissue signals in different MRI technique.

Warthin’s tumor

Synonyms: Papillary cyst adenoma lymphomatosum, adenolympoma and lymphomatous adenoma.

-benign tumor arising from proliferating salivary

ducts trapped in lymph nodes during embryogenesis of salivary gland.

Disease mechani

sm

Imaging Features

MDCT and MRI imaging are the

preferred technique for

imaging .

MDCT

-This tumor may be either soft tissue or cystic density.

MRI• It is heterogeneous and

demonstrate haemorrhagic foci .

Ulltrasonography • As a solid

mass(anechoic),unless the mass is cystic .

Hemangioma

Synonym

Vascular

Nevus

Disease Mechanis

m

Benign neoplasm of proliferating

endothelial cells

Vascular malformation, including from abnormal vessel morphogenesis

• When this tumor occurs in association with salivary gland, the ducts of gland may be displaced curving about the mass

Sialography

Imaging features

MDCT Imaging

Phleboliths, discrete soft tissue calcifications associated with vascular lesion .

Shows hemangioma as a soft tissue mass that is well distinguished from the surrounding tissue, especially when intravenous contrast enhancement is used.

MRI• The tumor has signal similar to that of adjacent

muscle on T1-weighted images and very high signal on T2-weighted images.

• Well-defined margin.• Strongly hypoechoic hemangioma may have

complex appearance resulting multiple interfaces in the lesion.

• Phleboliths are seen as multiple hyperechoic areas within the body of the gland itself.

Ultrasonography

Malignant TumorsClinical features

20% of tumor in the parotid are malignant compared with 50% or 60% of submandibular tumors, 90% of sublingual tumors and 60% to 75% of minor salivary gland tumors.

Imaging features

The imaging presentation of malignant tumors is variable.

Related to grade, aggressiveness, location and type of tumor.

Features such as ill-defined margin, invasion of adjacent soft tissues(e.g. fat species) and destruction of adjacent osseous structures are considered to be typical indicators of malignancy.

Treatment

• Typically surgical.• Low-grade malignant tumours of the

parotid gland may be partially incised or totally excised.

• Submandibular and sublingual glands totally excised.

• High-grade tumors may require radical neck dissection.

• Combination of surgery, therapeutic radiation, and chemotherapy .

Mucoepidermoid Carcinoma

• Is a malignant tumor composed of a variable admixture of epidermoid and mucous cells arising from the ductal epithelium of the salivary glands.

Disease Mechani

sm

Clinical features Most common malignant salivary gland tumor.Commonly in the parotid gland; minor gland ,with

the palate being the most frequent location .A wide age range exists, with the highest

prevalence in the fifth decade of life .Clinically, this tumor appears movable, slowly

growing, painless nodule.Usually only 1to 4 cm in diameter.Prognosis is good ; the 5 year survival rate is

greater than 95%.

Imaging Features

Cavitary sialectasia and ductal displacement may be noted.

Irregular homogeneous mass, slightly more dense than glandular parenchyma

Homogeneous low signal intensity on T1-weighted image.T2-weighted image are more heterogenous and intense.

Radiographic appearances in various salivary gland lesions

lesions Appearances

Sjogren ‘s syndrome Cherry blossom appearance Branchless fruit laden tree appearance

Benign salivary gland tumor Ball in hand appearance

Sialodochitis Sausage-string appearance

Conclusion• As salivary gland lesions form the major part of

orofacial disorder, it is very essential for us to know the various radiographic features and appearances so it is helpful for us to give early diagnosis and proper treatment planning

References

1. Oral Radiology – Stuart.C.White Michael J. Pharoah

2. Text book of Oral Medicine and Oral Radiology - Ravikiran Ongole

Thank-You