CHAP6-Diseases of the Salivary Glands

Comprehensive vocabulary flashcards covering the classification, anatomy, physiological properties, diagnostic imaging, and pathology of salivary gland diseases.

Salivary Glands

A group of simple and compound exocrine glands that secrete saliva into the oral cavity through ducts, and are considered as one of the four accessory organs/glands of digestion.

4 accessory organs/glands of digestion

1. liver

2. gallbladder

3. pancreas

4. salivary glands

liver

largest gland of the body that produces bile

gallbladder

stores & concentrates bile, and secretes enzymes

pancreas

produces pancreatic juice

salivary glands

secretes saliva that contains amylase / ptyalin

Classification of salivary glands

I. major salivary glands

II. according to ductal systems

III. according to the type of secretion

I. according to size and function

1. major salivary glands

2. minor salivary glands

Major Salivary Glands

Large, paired glands that secrete saliva and account for about $90\%$ of salivary secretions.

major salivary glands

a. parotid gland

b. submandibular glands

c. sublingual gland

Parotid Gland

The largest of all salivary glands ($15 - 30\,\text{gm}$) with a wedge shape resembling an inverted pyramid.

located in the retromandibular fossa anterior to the ear and sternocleidomastoid muscle, secreting about $25\%$ of total salivary volume.

duct: stensen’s duct

Stensen's Duct

The excretory duct of the parotid gland that opens inside the cheek opposite the crown of the maxillary second molar.

Submandibular Gland

A hook-shaped, walnut-sized major salivary gland ($7 - 15\,\text{grams}$ / about ½ the size of the parotid gland) located on the ventral sides of the neck under the chin and tongue, producing the majority of saliva at approximately $60 - 65\%$ of total volume.

duct; wharton’s duct

Wharton's Duct

The excretory duct of the submandibular gland that opens at the lateral side of the lingual frenum.

Sublingual Gland

The smallest of the major salivary glands, almond-shaped and about $\frac{1}{5}$ the size of the submandibular gland, located on the floor of the mouth under the tongue, producing about $5\%$ of total salivary volume.

ducts: ducts of rivinus

Ducts of Rivinus

composed of several small ducts which opens on the floor of the mouth / beneath the tongue, with one main & larger duct known as Bartholin’s duct

Bartholin's Duct

The main and larger duct of the sublingual gland that opens near, but independently from, the submandibular gland.

Minor Salivary Glands

A collection of $800 - 1{,}000$ small glands distributed along the mucosal surfaces of the oral cavity and throat that account for approximately $10\%$ of salivary secretions.

minor salivary glands:

1. lingual glands

2. buccal glands / molar glands

3. labial glands

4. incisive glands

5. palatine glands

6. glossopalatine glands

7. carmalt’s glands

1. lingual glands

a. blandin & nuhn glands / glands of blandin & nuhn’s

b. von ebner’s glands / glands of von ebner

c. weber’s glands / glands of weber

A. Blandin & Nuhn Glands

Anterior lingual glands located at or near the apex of the tongue whose ducts open onto the ventral surface of the tongue.

B. Von Ebner's Glands

Posterior lingual serous glands located between muscle fibers of the tongue beneath the circumvallate papillae, emptying into the trough of the vallate papillae.

C. Weber's Glands

Posterior lingual mucus glands situated in the peritonsillar space superior to the tonsils in the soft palate, with ducts opening onto the dorsal surface of the tongue.

*some do not classify weber’s glands as part of the lingual glands, but are considered separate minor salivary glands with emphasis on their association with the tonsils

buccal glands / molar glands

sparse and located in the inner cheek between the mucus membrane & the buccinator muscle

labial glands

numerous; near the midline and situated on the submucosa of the upper & lower lips

incisive glands

located on the floor of the mouth behind the lower incisors

palatine glands

found under the mucus membrane of the soft palate, posterolateral part of the hard palate, & uvula

glossopalatine glands

located in the isthmus region of the glossopalatine fold, but may extend to the glands of the soft palate

Carmalt's Glands

Minor mucous salivary glands situated in the retromolar area.

II. according to ductal systems

1. simple glands

2. compound glands

Simple Glands

single or unbranched ductal system of complex glands which are present in some minor salivary glands.

Compound Glands

branched ductal systems of complex glands as seen in major salivary glands.

III. according to the type of secretion

1. serous glands / pure serous glands

2. mucous glands / pure mucous glands

3. mixed glands

1. Serous glands / pure serous glands

consists of serous acinar cells which secretes thin & watery saliva

includes the ff: parotid glands & von Ebner’s glands

2. mucous glands / pure mucous glands

made of mucous acinar cells that discharge thick & vicsous saliva with high (glycoprotein) content

includes the FF: weber’s glands, palatine glands, glossopalatine glands, carmalt’s glands

3. mixed glands

composed of both serous acinar cells & mucous acinar cells

includes the FF: submandibular glands, sublingual glands, labial glands (with predominant mucous cells), buccal glands / molar glands (with predominant mucous cells), Blandin & Nuhn’s glands (with predominnt mucous cells)

*some may classify labial glands, buccal glands, and Blandin & Nuhn’s glandunder mucous glands due to predominant mucous cells

Salivon

The basic functional secretory unit of salivary glands.

Saliva

complex biological fluid from salivary glands to maintain the structure & function of the oral cavity

Properties of Saliva

1. volume

2. consistency

3. pH level

4. tonicity

5. specific gravity

Normal Salivary Secretion Properties

Daily volume of $0.5 - 1.5\,\text{liters/day}$ ($\approx 1\,\text{mL/minute}$), resting unstimulated flow rate of $0.3 - 0.4\,\text{mL/minute}$, stimulated flow rate of $1.5 - 2\,\text{mL/minute}$, slightly acidic pH of $6.7 - 7.4$, hypotonic to plasma, and specific gravity of $1.002 - 1.012$.

volume

0.5-1.5 liters/day or approximately 1mL/minute

-unstimulated flow rates: 0.3-0.4 mL/minute

-stimulated flow rates: 1.5-2mL/minute

consistency

clear to slightly cloudy (due to the presence of mucins & other cells

pH level

mixed saliva from all glands is slightly acidic at a 6.7-7.4 pH level (but may be alkaline at high salivary secretion rates

tonicity

hypotonic to plasma

specific gravity

ranges between 1.002-1.012

composition of saliva

I. 99.5% water

II. 0.5% solids (organic substances, inorganic substances, gases)

*glucose is normally absent in salivary glands, except in the patients with diabetes mellitus

1. organic substances in saliva

a. enzymes (ptyalin, maltase, lingual lipase,,, lysozyme; phosphatase; carbonic anhydrase; kallikrein)

b. other organic substances (mucin, albumin, lactoferrin, igA, etc.,,)

3 main digestive enzymes in saliva

1. salivary amylase / ptyalin

2. maltase

3. lingual lipase

2. inorganic substances

includes sodium, calcium, potassium, bicarbonate, bromide, chloride, fluoride, & phosphate

3. gases

such as oxygen, carbon dioxide, and nitrogen

functions of saliva

1. lubrications of teeth & mucosa

2. aids in bolus formation of food for swallowing

3. facilitates the mastication of food

4. serves as a solvent for molecules to stimulate the taste & detection of food

5. initiates digestion through enzymes

6. cleanses the mouth, teeth, & gums

7. buffering function to keep salivary pH levels within normal limits

8. prevents infections through its antimicrobial components

9. protects the mucus membranes from injury by diluting hot or irritating substances

10. maintains the integrity of the mucus membranes

11. its anti-carcinogenic activity limits the penetration of potential toxins & hazardous agents

12. contributes to articulation & phonation during speech

13. helps in the remineralization of teeth including protection against demineralization

14. accelerates soft tissue repair in the presence of oral cavity & in cases of esophageal damage

15. excretory function for heavy metals, alkaloids, microorganisms, & antibiotics

16. regulation of body temperature

17. regulation of water balance

phases of salivary secretion

1. cephalic

2. buccal

3. esophageal

4. gastric

5. intestinal

phases of swallowing

1. oral phase (voluntary)

2. pharyngeal phase (involuntary/reflex)

3. esophageal phase (involuntary/reflex)

diagnostic modalities for salivary glands diseases

1. history taking & clinical / physical examination

2. plain-film radiographs

3. ultrasonography

4. computed tomography scan

5. magnetic resonance imaging scan

6. positron emission tomography scan

7. serologic evaluation

8. histopathology

9. angiograph / arteriography

10. sialography / ptyalography

11. sialoscintigraphy / salivary scintigraphy / radionuclide imaging / radioactive isotope scanning

12. sialochemistry

13. sialometry

14. sialoendoscopy

3. ulrasonography

utilizes high-frequency sound waves to produce images of structures within the body without the use of radiation

4. computed tomography scan

uses several x-ray images that can show in detail the different levels of bone density including the muscles, fat, & tissues inside a solid organ

5. magnetic resonance imaging scan

utilizes magnetic fields & radio waves to generate a detailed image of the body’s bones, organs, and tissues without the use of radiation

6. positron emission tomography scan

uses radioactive positrons to detect cellular level changes in the metabolic & chemical activity of the body

7. serologic evaluation

various laboratory techniques that focuses on blood serum for evidence of infection by evaluating antigen-antibody reactions

8. histopathology

a. fine needle aspiration biopsy

b, frozen section

c. salivary gland biopsy

fine needle aspiration biopsy

refers to the use of a thin, hollow needle (21-25g) that is inserted into the mass to collect material for cytologic diagnosis

frozen section

intraoperative procedure that differentiates between benign & malignant tumors, evaluates tissue margins for involvement by malignancy, and determines the type of tissue involved

salivary gland biopsy (incisional or excisional)

may be utilized in the diagnosis of major salivary gland lesions, but it is commonly used as an aid in the diagnosis of Sjogren’s syndrome

9. angiograph / arteriography

possesses the ability to localize and catheterize arterial channels supplying the salivary gland structures

10. Sialography

The gold standard radiographic procedure for demonstrating salivary ductal architecture through the injection of a radiopaque contrast medium into the ductal system.

Phases of a Complete Sialogram

The three successive imaging stages consisting of the

a. ductal phase (immediate visualization of major ducts),

b. phase (minutes later, parenchymal filling),

c. evacuation phase (assessment of secretory clearance).

a. ductal phase

immediately after introduction of the contrast media which allows visualization of the major ducts

b. acinar phase

occurs minutes after the ductal system is fully opacified with contrast media and the gland parenchyma is filled with contrast

c. evacuation phase

assess the normal secretory clearance function of the gland and accentuates any ductal pathology that is not detected in other phases

11. Salivary Scintigraphy (Sialoscintigraphy)

provides information on the functional capabilities of the salivary gland by assessing by abnormalities in salivary gland uptake &excretion through the intravenous injection of a radioactive isotope called technetium-$99\text{m}$ ($^{99\text{m}}\text{Tc}$) pertechnetate which is a pure gamma ray emitting nucleotide

12. Sialochemistry

Laboratory examination of the electrolyte composition of saliva, focusing particularly on sodium and potassium levels.

13. Sialometry

The clinical procedure of measuring salivary flow and production volume to evaluate salivary gland function.

14. Sialoendoscopy

Minimally invasive transluminal endoscopic visualization of the major salivary gland ductal systems used for both diagnosis and treatment of ductal pathology.

Duct Atresia

Congenital absence or occlusion of the orifice of a major salivary gland duct or part of the duct itself, leading to severe xerostomia and salivary retention.

Heterotopia (Salivary Aberrancy)

Normal salivary gland tissue situated in an abnormal anatomical location anywhere within the territory of the 1st and 2nd branchial arches.

Choristoma

A tumor-like mass of histologically normal tissue that is foreign to the anatomical site where it is found.

Hypoplasia vs. Atrophy

Hypoplasia refers to a decrease in the number of cells before an organ reaches full development, whereas atrophy is a decrease in size or functionality occurring after full development has been attained.

Hyperplasia vs. Hypertrophy

Hyperplasia is an increase in organ or tissue size caused by an increase in the number of cells, whereas hypertrophy is an increase in size caused by enlargement of existing cells.

Mumps (Epidemic Parotitis)

An acute, contagious viral infection caused by an RNA paramyxovirus transmitted via direct contact with salivary droplets, typically causing painful unilateral or bilateral parotid swelling.

Kuttner's Tumor (Chronic Sclerosing Sialadenitis)

A benign, typically unilateral chronic inflammation commonly affecting the submandibular gland that progresses with increasing fibrosis and parenchymal atrophy, forming a firm tumor-like mass.

Sialosis (Sialadenosis)

A chronic or recurrent, diffuse, non-inflammatory, non-neoplastic swelling of the major salivary glands (primarily the parotids), frequently associated with malnutrition, endocrine disorders, or alcoholism.

Sialolithiasis

The formation of calcific concretions (calculi composed predominantly of calcium phosphate, carbonate, and an organic nidus) within the parenchyma or ducts of salivary glands.

Mucous Retention Cyst

A true cyst lined by epithelium that arises secondary to ductal obstruction (such as a sialolith) leading to accumulation of salivary fluid.

Mucous Extravasation Cyst

A false cyst or pseudocyst lacking an epithelial lining, formed by the rupture of a salivary duct and pooling of mucus into surrounding granulation and connective tissue.

Ranula

A mucous extravasation cyst arising from the sublingual or submandibular gland, presenting as a bluish, dome-shaped swelling on the floor of the mouth resembling a frog's belly.

Sjogren's Syndrome Triad

The clinical combination of keratoconjunctivitis sicca (dry eyes), xerostomia (dry mouth), and rheumatoid arthritis or other connective tissue disease.

Primary vs. Secondary Sjogren's Syndrome

Primary Sjogren's syndrome (sicca complex) occurs alone without an associated autoimmune connective tissue disorder; secondary Sjogren's syndrome occurs alongside another autoimmune condition such as rheumatoid arthritis or systemic lupus erythematosus.

Mikulicz's Disease

An IgG4-related disease characterized by symmetric, bilateral, non-specific enlargement of $\ge 2$ salivary and lacrimal glands resulting from lymphoid tissue infiltration.

Heerfordt's Syndrome (Uveoparotid Fever)

A specific manifestation of sarcoidosis characterized by firm, painless, bilateral parotid enlargement, uveitis, low-grade fever, and facial nerve palsy.

Pleomorphic Adenoma

The most common benign salivary gland neoplasm (benign mixed tumor), slow-growing, painless, firm, and rubbery, composed of epithelial, myoepithelial, and mesenchymal stromal elements.

Warthin's Tumor (Papillary Cystadenoma Lymphomatosum)

The second most common benign salivary gland neoplasm, presenting as a slow-growing, doughy, compressible mass containing epithelial components forming cystic structures within lymphoid stroma.

Canalicular Adenoma

A benign epithelial tumor occurring predominantly in minor salivary glands (frequently upper lip), characterized histologically by double rows of columnar epithelial cells arranged in parallel cords.

Mucoepidermoid Carcinoma

The most common malignant salivary gland neoplasm, characterized histologically by varying proportions of mucous, intermediate, and epidermoid (squamoid) cells.

Adenoid Cystic Carcinoma

A malignant salivary gland tumor characterized by a cribriform ('Swiss-cheese') or tubular growth pattern with a marked tendency to invade along nerve sheaths (perineural spread).

Polymorphous Low-Grade Adenocarcinoma

A slow-growing malignant salivary neoplasm exhibiting architectural diversity within a single tumor and distinctive concentric whorling of tumor cells around nerve endings.

Modified Schirmer's Test (Salivary)

A chairside test measuring salivary production with a $35\,\text{mm}$ calibrated filter paper strip; wetting of $<15\,\text{mm}$ after $5\,\text{minutes}$ indicates xerostomia, whereas $>33\,\text{mm}$ indicates sialorrhea.

Sialorrhea (Ptyalism)

An excessive flow or secretion of saliva leading to involuntary drooling, defined clinically as unstimulated salivary flow exceeding $0.4\,\text{mL/minute}$ or stimulated flow exceeding $2.0\,\text{mL/minute}$.

Water Brash

Episodic reflex hypersalivation triggered as a protective buffering response to neutralize stomach acid in patients with gastroesophageal reflux disease (GERD).

Necrotizing Sialometaplasia

A benign, self-limiting, ulcerative inflammatory lesion usually involving the palatal minor salivary glands that clinically and histologically mimics squamous cell carcinoma or mucoepidermoid carcinoma.

Bogorad's Syndrome (Crocodile Tears Syndrome)

A condition characterized by unilateral gustatory hyperlacrimation (crying triggered by eating or drinking) caused by aberrant misdirected regeneration of injured facial nerve fibers into the lacrimal gland.