Diseases of Salivary Glands

Prepared By: Dr. Ahlam A. Alesayi

MAJOR

1-PAROTID2-SUBMANDIBULAR3-SUBLINGUAL

Salivary Glands MINOR

FOUND IN ALMOST EVERY PART AT THE ORAL CAVITY EXCEPT THE GINGIVA AND HARD PALATE

Salivary Gland Disease

Organic Disease

Caused by systemic factors such as

-Neurological disease, Drug therapy and endocrine disturbance

Diseases of salivary gland :

Developmental anomalies Sialadenitis Obstruction and traumatic lesions SjÖgren syndrome Sialadenosis HIV-associated salivary gland disease Salivary gland tumour Age changes in salivary gland

1- Developmental anomalies

Aplasia of one or more major glands and atresia of one or more major salivary gland ducts.

Congenital aplasia of the parotid gland may be associated with other facial abnormalities e.g mandibulofacial dysostosis, aplasia of the lacrimal gland and hemifacial microsomia.

Heterotopic salivary tissue in a variety of sites in head and neck, most frequent at the angle or within the body of the mandible ( present as stafne’s idiopathic bone cavity).

Accessory parotid tissue within the cheek or masseter muscle.

2- Sialadenitis

Inflammatory disorders of the major salivary gland are usually result of bacterial or viral infection but occasionally due to other causes such as trauma, irradiation and allergic reactions.

SialadenitisBacterial

Viral Postirradiation

Sarcoidosis

Sialadenitis of minor gland

Acute

ChronicMumps

Cytomegalic inclusion disease

A- Acute Bacterial Sialadenitis

- Uncommon disorder principally involve the parotid gland.

- Acute parotitis is an ascending infection ( Bacterial reach the gland from the mouth by ascending the ductal system).

Etiology : Streptococcus pyogenes and staphylococcus aureus , less common Haemophilus species or members of the black-pigmented bacteroides group.

- Reduced salivary flow is the major predisposing factor.- Acute parotitis may occur in patients with sjogren

syndrome or following the use of drugs with xerostomic side-effect.

- Acute infection may arise in immunocompromised patients or as result of acute exacerbation in a previously chronic sailadenitis.

Clinical feature: - The onset is rapid.- Swelling accompanied by pain , fever ,

malaise and redness of overlying skin.- Pus may be expressed from effected

duct.

B- Chronic bacterial sailadenitis

- Non-specific inflammatory disease associated with duct obstruction ( due to salivary calculi) and low grade ascending infection.

- The submandibular gland more common than parotid.

Clinical feature:

- Usually, unilateral and symptoms of recurrent tender swelling of the effected gland to associated obstruction.- The duct orifice appear inflamed.- Purulent or salty-tasting discharge ( in acute

exacerbations ).

Histological examination:

- Dilatation of the ductal system.- Hyperplasia of duct epithelium.- Periductal fibrosis and acinar atrophy with replacement

fibrosis.- Chronic inflammatory cell infiltration.

- In sialography may see the duct obstruction, destruction of glandular tissue and duct dilatation ( sialectasia ).

- Progressive chronic inflammation in submandibular gland may result in almost complete replacement of the parenchyma by fibrous tissue producing a firm mass that may be mistaken clinically for a neoplasm.

Recurrent parotitis:

- Is a rare disorder may effect children or adults.- Rarely the adults form following from

childhood type, due to persistence of factors (calculi or duct strictures) leading to recurrent attacks of low-grade ascending infection.

The aetiology of childhood type is unclear

- Low secretion rate predisposing to ascending infection.

- Immaturity of the immune response in infants.- Congenital abnormalities of the ductal system.

Clinical feature:

- Unilateral or bilateral.- Recurrent painful swelling of the gland.- Pus may be expressed from the duct orifice.- In most cases the condition resolves

spontaneously by the time but repeated infection may result in irreversible damage to the main duct lead to duct obstruction then lead to ascending infection and damage then recurrent parotitis in adult life.

B- Viral Sialadenitis:

Mumps ( epidemic parotitis )

- It is the commonest cause of parotid enlargement and the commonest of all the salivary gland diseases.

- Is an acute, contagious infection, which often occurs in minor epidemics.

Etiology: Caused by a paramyxovirus.

- The virus is transmitted by direct contact with infected saliva and by droplet spread.

Incubation period of 2-3 weeks.

Clinical feature:

- None-specific prodromal symptoms of fever and malaise followed by sudden onset of painful swelling in one or more salivary glands (parotid glands are always involved bilaterally in about 70% of cases.- Occasionally the submandibular and sublingual

gland may be affected (rarely without parotid involvement)

- The gland enlargement gradually subsides in about 7 days.

- The virus is present in the saliva 2-3 days before the onset of disease and for about 6 days afterwards.

- Occasionally, in adult other internal organs are involved such as testes, ovaries, central nervous system and pancreas (orchitis is common complication is 20% of cases in adult males).

- Recurrent of infection is rare (long lasting immunity).

Diagnosis:

- Is usually made on clinical grounds.- In atypical cases can be confirmed by the

detection of , IgM , antibodies and in serum antibody titer to mumps virus antigens.

B- Cytomegalic inclusion disease (Salivary Gland inclusion disease)

- Infection with cytomegalovirus (member of the herpesvirus group).

- Most primary infection are asymptomatic but the virus can cause severe disseminated disease in neonates and immunocompromised host (such as transplant patients and HIV-infected patients).

- Usually, incidental histological finding.

- Presence of large, doubly contoured “owl-eye” inclusion bodies within the nucleus or cytoplasm of duct cells of the parotid gland.

- Similar inclusion frequently occur in the kidneys, liver, lungs, brain and other organs.

C- Postirradiation sialadenitis:

-is common complication of radiotherapy and there is a direct correlation between the dose of irradiation and the severity of the damage.-if the damage is severe, it would be irreversible leading to fibrous replacement of the damage acini and squamous metaplasia of ducts.-in less severe damage, some degree of function may return after several months.-serous acini are more sensitive to radiation damage than mucous acini.

D- Sarcoidosis:

-systemic chronic granulomatous disorder of unknown aetiology.-most common effects young adults.-present most frequently with bilateral hilar lymphadenopathy , pulmonary infiltration and skin or eye lesion.-oral mucosa involvement is rare(incident onset, signs and symptoms disappear in time but some time leave residual swelling.-they may effect the parotid and minor salivary gland.

- parotid involvement present as persistent, often painless, enlargement and may be associated with involvement of the lacrimal glands in heerfordt syndrome or uveoparotid fever ( sarcoidosis with combination of uvitis, parotitis and facial paralysis).

E- Sialadenitis of minor salivary gland :

-is often an incidental and insignificant finding.-it is seen most frequently in association with mucous extravasation cysts and stomatitis nicotina of the palate.-very rarely, it is present with multiple mucosal swellings associated with cystic dilatation of ducts and chronic suppuration, this condition referred to( stomatitis glandularis). It occur most commonly on the lips.

2-Obstractive and traumatic lesions :

Duct obstruction and trauma are important factor in the aetiology of other disease such as chronic sialadenitis in major gland and mucoceles in minor gland (salivary cyst).Causes: 1-due to a blockage within the lumen.2-result from disease in or around the duct wall such as fibrosis or neoplasia.3-obestruction to the duct orifice is due to chronic trauma such as sharp cusps or over-extended denture resulting in fibrosis and stenosis.

A-salivary calculi (sialoliths):

-it is cause obstruction within the duct lumen.-can occur at any age , more common in middle-aged adults.-submandibular gland is most frequently involved 70-90% of cases , parotid gland is the next commonly involved whereas sublingual and minor gland is uncommon.-the aetiology and pathogenesis of salivary calculi are largely unknown, it is generally thought that they form by deposition of calcium salts around an initial organic nidus which might consist of altered salivary mucins together with desquamated epithelial cells and microorganisms.-calculi are usually unilateral, may form in ducts within the gland or in the main excretory duct, multiple stone in the same gland are not uncommon.

-the typical sign and symptom are pain and sudden enlargement of the gland, especially at meal time when salivary secretion is stimulated.-the reduction of salivary flow( predispose to ascending infection and chronic sialadenitis).-the calculi my detected by palpation and on radiograph, and may be round or ovoid, rough or smooth, and vary in size.-they are usually yellowish in color and composed from calcium phosphates and smaller amount of carbonates.

B- Necrotizing sialometaplasia:

-is a relatively uncommon disorder which clinically and on histological examination may be mistaken for malignant disease.

Aetiology:Is unknown, but ischaemia leading to infarction of salivary lobules is the most accepted theory. In some patient there may be history of trauma from a variety of causes, including local anesthetic injection and previous surgery.

Clinically

It occur most frequently on the hard palate in middle-aged patient ,and is about twice as common in men as women. -it present as a deep crater-like ulcer which may mimic a malignant ulcer and take up to 10-12 weeks to heal.

Histopathological examination:

-lobular necrosis of salivary gland, squamous metaplasia of ducts and acini , mucous extravasation, and inflammatory cell infiltration.-the overlying palatal mucosa show pseudoepitheliomatous hyperplasia and the histopathological feature may be mistaken for either squamous cell carcinoma or mucoepidermoid carcinoma.

3- SJÖGREN SYNDROME:Is chronic autoimmune disease characterized by lymphocytic infiltration and acinar destruction of lacrimal and salivary glands leading to dry eyes (keratoconjunctivitis sicca ) and dry mouth (xerostomia).Classification:1-primary sjÖgren syndrome: combination of dry mouth and dry eye.2-secoundary sjÖgren syndrome: occurs in association with another autoimmune connective tissue disease, most frequently rheumatoid arthritis or systemic lupus erythematosis (this type occur in about half of the cases).

Aetiology:

The specific cause of this syndrome is unknown, it considered a multifactorial process, with immunological alteration indicating a disease of great complexity.- sjÖgren syndrome occurs with increased frequency in patient with HLA class 11 genes and several virus especially Epstein-barr virus.

>Clinical features:-predominantly affects middle-aged female (female : male ratio is about 9:1)- the most common symptoms are dryness and soreness of mouth and eyes.-xerostomia may caused difficulty in swallowing and speaking ,increased fluid intake and disturbance of test.-Xerostomia may result in oral candidosis, bacterial sialadenitis and dental caries and periodontal disease .-oral mucosa appear dry, smooth and glazed.

-tongue: the dorsum of the tongue appearing red and atrophic and showing varying degree of fissuring and lobulation.-salivary gland enlargement is very variable (in 30% of patient) , this enlargement is bilateral, parotid gland most common and is seldom painful. -keratoconjunctivitis sicca manifests as dryness of the eyes with conjunctivitis and cause gritty and burning sensation. Lacrimal gland enlargement is uncommon.

sjÖgren syndrome might be involved abnormalities of other exocrine glands and variety of extra glandular manifestations:

Glandular ( exocrine glands )SalivaryLacrimalSkinRespiratory tractPharynx and GI tractReproductive system

ExtraglandularJoints SkinLiverRenalEndocrineNeurologicalHaematologicalimmunological

- Xerostomia- Xerophthalmia- Xeroderma- Nasal dryness, Sinusitis, tracheitis- Dysphagia, atrophic gastritis, pancreatitis- Vaginal dryness

- Arthritis - Purpura, Raynaud’s phenomenon- Primary biliary cirrhosis- Renal tubular defects - Thyroiditis- Central and peripheral neuropathies- Anaemia, Leucopenia, Thrombocytopenia- Autoantibodies, Hypergammaglobulinaemia

>Histopathological examination:-lymphocytic infiltration, initially around intralobular ducts, thin replaces the whole of the affected lobules.-the infiltration is accompanied by acinar atrophy but the ductal epithelium may show proliferation. This hyperplasia obliterates the duct lumen leading to islands of epithelial tissue in a sea of lymphocytes, replacing entire salivary lobules. This appearance called benign lymphoepithelial lesion or myoepithelial Sialadenitis.-the benign lymphoepithelial lesion is characteristic but not pathognomic of sjÖgren syndrome, it also develops in in the sialadenitis associated with hepatitis c virus infection and in HIV-associated salivary gland disease.

Investigation:-labial gland biopsy to assess focal lymphocytic sailadenitis.-autoantibody screen to detect anti-Ro and anti-La (also referred to as SS-A and SS-B) antibodies. >anti-Ro antibodies are found in 75% of patient with primary sjÖgren syndrome , and also found in secondary type. >anti-La antibodies found in 40% of patient with sjÖgren syndrome.-assessment of salivary gland involvement –sialography (show varying degree of sialectasis, often producing snowstorm or cherry tree in blossom-like appearance).-assessment of salivary gland function – salivary flow rates-ophthalmic opinion to assess ocular signs.* sjÖgren syndrome may progress to B cell, malignant lymphoma( in late stage)

4-Sialadenosis: -is a condition characterized by non-inflammatory, non-neoplastic , recurrent bilateral swelling of salivary gland.-parotid glands are most common affected.-it is probably due to abnormalities of neurosecretory control and association with other conditions such as hormonal disturbances, malnutrition, liver cirrhosis, chronic alcoholism and following the administration of various drugs.-histological:Is characterized by hypertrophy of serous acinar cells to about twice their normal size , and the cytoplasm is often densely packed with secretory granules.

5-HIV-associated salivary gland disease:

-salivary gland disease may be feature in a small proportion of adult with HIV infection. (higher in infected children).-xerostomia and swelling of major glands, almost the parotid.-xerostomia may be caused by a sjÖgren syndrome –like disease associated with a benign lymphoepithelial lesion, but the patient do not show the autoantibody profile commonly seen in sjÖgren syndrome.-parotid swelling may be due to enlargement of intraparotid nodes as part of persistent generalized lymphadenopathy or due to the development of multiple lymphoepithelial cysts of varying size within the nodes.

Salivary gland tumours :About 40 different types of salivary glands tumour are now recognized .Classification of salivary tumours by WHO:

- there are primary neoplasm of epithelial origin.

1-Adenomas:(benign tumour)

A- Pleomorphic adenoma:- The commonest type of salivary gland tumour (60-

65%) of all tumours of the parotid gland and 45% of all tumours of the minor glands (more common palate).

- Can occur at all ages but the majority in the 5th and 8th decades of life and more common in female.

- Usually solitary, recurrences may be multifocal.- Presents as: Slowly growing, painless, rubbery and

the overlying skin or mucosa is usually intact.

Histological:

- The term pleomorphic or (mixed tumours) described the varied appearance of the lesion rather than implying a dual origin from epithelium or mesenchyme.

- The tumour is composed of cells of epithelial and myoepithelial origin.

- The tumour is clearly demarcated.- Sometimes, isolated nodules of tumour may be

seen within or even outside the capsule giving the impression of invasive growth but these are out growths of the main mass.

Microscopically:

- Architectural diversity of epithelial and stromal component.

- The epithelial may be arranged in duct-like structure or as sheets, clumps, and interlacing strands..

- The intercellular material is abundant, with presence of myxoid and chondroid areas (myxochondroid).

- In myxoid area epithelial cells widely separated and have long stellate processes and surround by mucoid material.

- In chondroid area isolated epithelial cells appear as rounded cells lying in lacunae within mucoid material (tissue resemble hyaline cartilage).

-

- Tumour rich in mucoid material tend to rupture more readily during surgical removal allowing spillage and implantation of tumour into surrounding tissues giving rise to multifocal recurrences.

- -malignant transformation can occur, usually in tumours that have been present for many years.

B-Warthin tumour ( adenolymphoma , papillary cystadenoma , lymphmatosum)

-almost occur in the parotid gland (bilateral).-is a slow growing lesion, may arise multifocally.-most patient are over 50 years of age.

*on section:The tumour has a papillary cystic structure and multiple , irregular cystic spaces containing mucoid material.

*microscopically:Tumour consist of epithelial and lymphoid elements.-the epithelium is double-layered , and the epithelial cells have esinophilic granular cytoplasm rich in abnormal mitochondria, they resemble oncocytes.*the histogenesis of the tumour is uncertain, but it most likely arises from residues of salivary duct epithelium entrapped within lymph nodes during development.

2-carcinomas:

-uncommon 1% or less of all malignancies and 5% of malignant tumours in head and neck region.

a-mucoepidermoid carcinoma:

-is the commonest malignant salivary gland tumour ( 10% of all salivary tumours).-most common in parotid, in the minor gland the palate is the most frequent site.-can occur at any age but the highest incidence is during 4th and 5th decades of life and slight female predominance.

*clinically:

the tumour present in similar mannar to pleomorphic adenoma but grossly cystic and may be accompanied by pain and ulceration.

*microscopically

- presence of squamous cells, mucous-secreting cells and cells of intermediate type which have the potential for further differentiation towards mucous or squamous cells.-there are two pattern of tumour, well differentiated (low grade) and poorly differentiated (high grade) , they are non-encapsulated and invasive.

>in well-differentiated type : may appear to advance on a broad pushing front , mucous cells predominate , mucin filled cysts and usually good prognosis. -Have local recurrence rate of less than 10% and 5-years survival of about 95%>in poor –differentiated type: ill-defined , highly infiltrative growths -epidermoid and intermediate cells predominate -solid rather than cystic pattern -usually poor prognosis -have local recurrence rate of 80% and 5-year survival rate of only 30-40%

b- Acinic cell carcinoma:-is an uncommon neoplasm , the great majority arising in the parotid gland (2-3% of all parotid tumours and up to 20% of malignant parotid neoplasms).Histological appearance:-consist of sheet or acinar groupings of large, polyhedral cell which have basophilic, granular cytoplasm, similar in appearance to the serous acinar cells of salivary glands.-other tumour may show a papillary cystic pattern.-acinar cell carcinoma is low-grade malignancy , five-year survival rates of 80-100% reported for well-differentiated tumour and 65% (or better) for poorly differentiated type.

C- Adenoid cystic carcinoma:-usually arise in middle-aged or elderly patients.-they account for up to 30% of minor salivary gland tumours (more in palate) but only for 6%of parotid tumours.*clinically:-present as slowly enlarging tumours, they are often present for several years.-pain and ulceration of the overlying skin or mucosa( this points used to distinguish this lesion clinically from pleomorphic adenoma).-parotid tumour may present with facial palsy, the neurological manifestation indicate the tumour infiltrate and spread along nerve pathways.

*Histopathological:-neoplastic epithelium is arranged as avoid and irregular shaped islands or anastomosing strands lying in a scanty connective tissue stroma.-there are three basic histomorphologic patterns :cribriform , tubular and solid.-the cribriform (or swiss-cheese)pattern: is common type, presence of numerous microscopic cyst like spaces within the epithelial islands and the epithelial consist of small, uniform polygonal cells with basophilic cytoplasm ,mitoses are rarely seen.

-the tubular and solid patterns are less frequently.-infiltration of adjacent tissues and spread along and nerves are often prominent feature and may be extensive.-metastatic spread tends to be via the bloodstream to the lungs.-the long-term prognosis is poor.-cribriform and tubular types have a better prognosis than solid type.

D-Carcinoma arising in pleomorphic adenoma:-is relatively uncommon , account for about 3% of salivary tumours.-almost all arise in adenomas of the parotid or submandibular that have been present for many years.-the diagnosis requires evidence of a pre-existing pleomorphic adenoma.-the malignant tumour is still confined by the capsule of the pre-existing adenoma (the in situ or non-invasive stage) the tumour has an excellent prognosis -when there is infiltration of surrounding tissue the tumour carries a poor prognosis

E-Polymorphous low-grade adenocarcinoma:

-occur almost in minor salivary gland , mostly in the palate.-has a variety of growth patterns within the same lesion , including solid , tubular , and cribriform area (mimic adenoid cystic carcinoma.-the tumour has an infilterative pattern of growth and (like the adenoid cystic carcinoma )can show perineural invasion.-tumour has a good prognosis , although it has an unpredictable potential to metastasis in about 15% of cases.

Age changes in salivary glands:

-in major and minor salivary glands.-reduction in the weights of submandibular and parotid glands have been reported with increasing age.-reduction in flow rate of submandibular gland with an age-dependent , will several studies have demonstrate that there is no significant reduction in parotid flow rates in the elderly.

-in both glands the reduction in weight is related to atrophy of secretory tissue and replacement by fibro-fatty tissue.-there is reduction in the volume of acinar tissue of about 30-35% from 20-75 years of age .-Similar change with 45% loss of acinar tissue in minor glands in lower lip.

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