BDS10020 Salivary Gland Diseases (Lecture) PDF

BDS10020 Salivary gland non-neoplastic diseases ` Aims: The aim of this lecture is to detail the principle histopathological features of common nonneoplastic salivary gland disease Objectives: On completion of this lecture, the student should be able to: Understand the principle histopathological fe...

BDS10020 Salivary gland non-neoplastic diseases ` Aims: The aim of this lecture is to detail the principle histopathological features of common nonneoplastic salivary gland disease Objectives: On completion of this lecture, the student should be able to: Understand the principle histopathological features of Sjogren’s syndrome, sialolithiasis, HIVrelated salivary gland disease, HCV-sialadenitis, sialosis, mucocele, ranula and non-specific chronic sialadenitis Inflammatory Cystic Obstructive Salivar y gland diseases Developmenta l Autoimmun e Disturbance of salivary flow Atresia Aplasia Aberrancy Developmental disturbances of salivary glands Aplasia: Complete absence of one or more salivary glands, due to failure of the terminal cells of a developing gland bud to differentiate into acinar tissue. Atresia is congenital absence or occlusion of one or more ducts of the major salivary glands, due to failure of canalization of the more proximal part of the epithelial salivary gland after the distal part has differentiated into salivary gland tissue. ♣Clinical significance Xerostomia (dry mouth) Aberrancy This is an ectopic condition in which normal secreting salivary gland tissue develops at an anatomically abnormal position. Latent Bone Cyst This is a condition in which part of the submandibular, or more rarely the sublingual, salivary gland may develop in a bony cavity or depression on the lingual surface of the body of the mandible maintaining its connection with its parent gland Latent bone cyst (Stafne Defect, static bone cyst)  It is asymptomatic, discovered coincidentally on radiographic examination,  Appears as round radiolucent area (most often situated in the molar-angle region) below the inferior alveolar canal and slightly above the lower border of the mandible If the diagnosis is in doubt CT, MRI & sialography could be used Latent bone cyst (Stafne Defect, static bone cyst) Sialography Cysts of the salivary glands Mucous extravasation cyst Mucous retention cyst pseudocyst True cyst Due to trauma of excretory duct Due to obstruction of salivary leading to escape of mucin into flow because of salivary duct surrounding connective tissue stone Mucous extravasation Mucous retention cyst cyst (mucocele) Clinical Mostly in minor salivary features glands (lip) in children & young adults Asymptomatic, soft, fluctuant swelling , appear bluish (superficial lesions) In major (more common) or minor salivary glands mostly in adults Asymptomatic, soft, fluctuant swelling , appear bluish Mucous extravasation cyst Histological Mucin pool surrounded features by a granulation tissue infiltrated by chronic inflammatory cells Mucous retention cyst Cystic cavity contains mucin & lined by ductal epithelium Ranula A clinical term that describes mucous retention & extravasation cysts in the floor of mouth [related to sublingual gland] and appear as blue fluctuant swelling Sialadenitis Inflammation of salivary glands that can arise from infectious & noninfectious causes Causes of Sialadenitis Non-infectious Infectious Bacterial Viral Acute & chronic sialadenitis-juvenile recurrent parotits Mumps (paramyxovirus)cytomegalovirus Sjogren syndromeradiation therapyallergens-necrotizing sialometaplasia-cheilitis glandularis Acute suppurative parotitis Most bacterial infections (mostly caused by staphylococcus & streptococcus species) arise as a result of decreased salivary flow allowing retrograde spread of bacteria throughout the ductal system (ascending infection) Surgical mumps After abdominal surgery, acute parotitis may arise because the patients are kept without food or fluids & received atropine during surgical procedure Acute suppurative parotitis Clinical Features:  Painful swelling of affected gland  The overlying skin is warm & erythematous  Low grade fever  Trismus  A purulent discharge from the duct orifice on pressure. Chronic sialadenitis Recurrent or persistent ductal obstruction can lead to chronic sialadenitis Clinical Features Periodic pain and swelling within the affected gland at mealtimes [when salivary flow is stimulated]. Histopathology of Sialadenitis Acute Sialadenitis Neutrophil (acute inflammatory cells) accumulation within ductal system & acini Normal Chronic Sialadenitis Chronic inflammatory cell infiltrate (lymphocytes & plasma cells) Atrophy of acini Ductal dilatation Juvenile recurrent parotitis  The 2nd most common inflammatory salivary disorder of children worldwide  Cause is unknown may be genetic factor—duct malformation Clinical Features  Recurring unilateral or bilateral non suppurative swelling  between the age of 3-6 years  Usually resolves around the time of puberty Juvenile recurrent parotitis Radiographic Features Sialography demonstrates sialectasia (ductal dilatation) Mumps: "Epidemic parotitis" Etiology: Paramyxovirus infection, the virus is transmitted by droplet infection. Clinical features:  Incubation period: 14-21-day before onset of symptoms.  Patients are contagious from 1 day before clinical symptoms appear, to 14 days after symptoms resolution. The incidence of mumps reduced dramatically by vaccination [MMR: measles, mumps & rubella] Mumps: "Epidemic parotitis" Clinical features: Prodromal symptoms:  Headache, low grade fever, malaise, anorexia and myalgia  Discomfort & swelling surrounding lower ½ of external ear and extending along inferior border of mandible  Enlargement of the glands begins on 1 side, followed by involvement of other side Complications  Postpubertal patients may be affected by orchitis (testicular inflammation) or oophoritis (inflammation of the ovaries),  Less commonly, meningitis, pancreatitis & myocarditis may occur Sialadenitis Inflammation of salivary glands that can arise from infectious & noninfectious causes Causes of Sialadenitis Non-infectious Infectious Bacterial Viral Acute & chronic sialadenitis-juvenile recurrent parotits Mumps (paramyxovirus)cytomegalovirus Sjogren syndromeradiation therapyallergens-necrotizing sialometaplasia-cheilitis glandularis Cheilitis glandularis Is an uncommon inflammatory condition of unknown etiology [may be actinic damage, tobacco & poor hygiene] Clinical Features Usually affects middle aged males>females Characteristically affects the lower lip, which appears: - enlarged - firm - everted [due to hypertrophy & inflammation of glands] Cheilitis glandularis Clinical Features  Red macular appearance [due to exposure of inflamed and dilated orifices of the labial mucous glands]  Pressure on the glands may produce mucopurulent secretions from the ductal openings Treatment & prognosis Vermilionectomy (lip shave) usually produce satisfactory cosmetic results Malignant transformation was reported in few cases Necrotizing Sialometaplasia Uncommon locally destructive inflammatory condition of salivary glands It mimics a malignant process clinically & microscopically Etiology It is believed to be due to ischemia of salivary tissue leading to local infarction Predisposing factors include:  Traumatic injuries  Dental injections  Ill fitting dentures Necrotizing Sialometaplasia Clinical Features  75% of cases affects the hard palate  It begins as a nonulcerated swelling associated with pain or paraesthesia  Within 2 to 3 weeks, necrotic tissue sloughs out, leaving a crater like ulcer  The patient may report “a part of my palate fell out” Necrotizing Sialometaplasia Histopathologic Features  Acinar necrosis but lobular architecture is preserved [helpful clue]  Liberation of mucin & an inflammatory response  Squamous metaplasia of the salivary ducts [may be striking, that is easily misdiagnosed as squamous cell carcinoma or mucoepidermoid carcinoma]  Frequent association with pseudoepitheliomatous hyperplasia of overlying epithelium [confirm mistaken impression] Necrotizing Sialometaplasia Histopathologic Features Necrotizing Sialometaplasia Treatment & Prognosis  Biopsy is usually indicated to rule out the possibility of malignant disease  Once diagnosis is reached no treatment is required  It resolves within 5 to 6 weeks Autoimmune salivary gland diseases An autoimmune response is a condition in which an individual's primary immune defense mechanism produces antibodies that are directed against and attacks his own tissues. Sjögren’s Syndrome Sjögren’s syndrome is chronic autoimmune disorder principally involving salivary and lacrimal glands resulting in xerostomia & xerophthalmia [their clinical presentation is called sicca syndrome] Sjögren’s Syndrome Two forms of the disease are recognized a-Primary Sjögren syndrome (sicca syndrome): Sicca syndrome alone, with no other autoimmune disorder b-Secondary Sjögren syndrome Patients manifest sicca syndrome in addition to systemic autoimmune disorders, such as rheumatoid arthritis or systemic lupus erythematosis. Sjogren’s syndrome Clinical features  Mainly affects middle aged females >males  xerophthalmia (dry eyes)  xerostomia (dry mouth & its consequences).  Keratoconjunctivitis sicca manifests as dryness with a gritty or foreign body burning sensation of eyes  Painless bilateral swelling of major salivary glands Diagnosis Sjogren’s syndrome  Stimulated parotid salivary flow rate is measured. (Normal 1- 2 ml per minute, but may be reduced to 0.5 ml/mm). Diagnosis Sjogren’s syndrome  Stimulated parotid salivary flow rate is measured. (Normal 1- 2 ml per minute, but may be reduced to 0.5 ml/mm).  Elevated erythro-sedimentation rate & serum IgG  Presence of a variety of autoantibodies [helpful clue] Two specific auto-antibodies SS-A (Ro) &SS-B(La) Circulating rheumatoid factor (RF) Anti-nuclear antibodies (ANA)  Sialography Sjogren’s syndrome Sialography – lack of normal branching of duct system – Snowflake pattern (snowstorm appearance) due to the escape of the contrast medium from the ducts – Radio-opaque contrast medium fills damaged areas, producing cherry blossom or branchless fruit-laden tree Sjogren’s syndrome Histopathology Lymphocytic infiltration. Leading to acinar destruction The ductal epithelium persists Formation of epimyoepithelial islands (proliferation of salivary gland ductal epithelium and myoepithelium) is common Sjogren’s syndrome Patients with Sjogren syndrome have a life time risk for lymphoma HIV-related salivary gland disease Clinical features Children and young adults with HIV infection may show Xerostomia Chronic soft parotid enlargement of one or both glands [sometimes painful] which could be due to: Multicystic lymphoepithelial lesions [sometimes termed cystic lymphoid hyperplasia (CLH) or benign lymphoepithelial lesion (BLEL) or benign lymphoepithelial cysts (BLEC)] HIV-related salivary gland disease intraglandular lymphadenopathy Kaposi’s sarcoma non Hodgkin’s lymphoma  acute suppurative sialadentis. Histopathologic features Non-specific histopathologic picture Similar to other chronic inflammatory conditions of the salivary glands HCV-Sialadenitis  Hepatitis C virus (HCV) is an enveloped RNA virus  HCV infection has several extrahepatic manifestations, including some oral manifestations such as:  Xerostomia  It causes a syndrome with features similar to Sjogren’s Sydnrome (SS) in a proportion of infected individuals [It is unclear if the virus may cause a disease mimicking primary SS or if HCV is directly responsible for the development of SS in a specific subset of patients]. HCV-sialadenitis Notably, some patients may present a triple association between HCV, SS-like sialadenitis and salivary gland lymphoma Histopathologic features Similar to other chronic inflammatory conditions of the salivary glands Sialadenosis (Sialosis)  Sialadenosis is an unusual noninflammatory disorder characterized by salivary gland enlargemnet, particularly involving the paratoid glands  The condition is associated with an underlying systemic problem such as diabetes mellitus, general malnutrition and alcoholism Sialadenosis (Sialosis) Resulting in dysregulation of innervation of salivary acini leading to excessive accumulation of secretory granules with marked enlargement of the acinar cells Obstructive salivary gland diseases Sialolithiasis (salivary stones) Definition: Existence of a calcified structure (calculi or stones) within the salivary ductal system They arise from deposition of calcium salts around a nidus of debris (bacteria, ductal epithelial cells or foreign bodies) It often develops in submandibular gland (80%) [due to the long, tortuous, upward path of Wharton’s duct & the thicker mucoid secretion of this gland] Obstructive salivary gland diseases Sialolithiasis (salivary stones) Clinical features:  Common in middle aged adults  It causes pain or swelling of the affected gland especially at meal time  Appear as radiopaque mass on radiographic examination Obstructive salivary gland diseases Sialolithiasis (salivary stones) Gross appearance Hard masses that are round, oval or cylindrical, yellow-white calcification usually