Introduction to Salivary Gland Pathology

Introduction to Salivary Gland Pathology

Introduction to Inflammatory and Infectious Pathology of the Salivary Glands

The medical pathology of the salivary glands is considered according to two frequently encountered clinical expressions:

• the increase in volume in the anatomical territory of a salivary gland,
• Disorders of salivary secretion, the most frequent of which is quantitative reduction, partial (hyposialia), or total (asialia or xerostomia)

However, we can distinguish three main chapters in the study of salivary gland pathologies:

• infectious pathology.
• lithiasis pathology.
• tumor pathology.

1. Reminder of fundamental concepts
   1. Anatomical reminders:
      1. Major or main salivary glands:
         1. Parotid gland

-Headquarters: parotid lodge

• It is the largest salivary gland, composed of two lobes: superficial and deep.
• Prismatic, triangular in shape, its weight ≈ 25gr.
• It is drained by the “Stenon” canal:
  • Length: 4-5 cm
  • Diameter: 1-2 mm
  • Termination: opposite the necks of the first or second upper molar.

-crossed by a vascular-nervous bundle:

• the external carotid artery
• The superficial temporal and internal maxillary veins
• The facial nerve with its two branches: temporofacial and cervicofacial

2. Submandibular or submandibular gland

-Seat: submaxillary compartment

• Drained by the Wharton Canal
• Weight ≈ 7gr
• Excretory canal “Wharton’s canal”:
  • Path: carried forward, up and inwards
  • Termination: sublingual caruncle (End < of the lingual frenulum)
• The vascular connections of the submandibular gland are with the facial artery and vein.

3. Sublingual gland

-Located in the floor of the mouth, below the mucosa of the alveolo-lingual sulcus

• Weight: 3 gr
• Has several canals, the most important: “Canal de Rivinus”

2. Accessory salivary glands:

They are scattered throughout the oral mucosa except the gum and the anterior region of the palate. Depending on their location, we distinguish: the labial glands, the jugal, palatine and velar glands, the retromolar trigone, the lingual glands and the sublingual glands.

2. Histological reminders:

The salivary glands are epithelial buds organized into lobes made up of several lobules, themselves formed of several acini.

The saliva secreted by the acini is collected by a network of canals differentiated into an intercalated canal for the acini and a striated canal for the lobule, which finally join the excretory canals.

Salivary glands can be:

-Serous.

-Mucosa.

-Seromucous.

1. The serous glands:

Containing only serous acini, they secrete serous saliva without mucin; these are the parotids and the lingual accessory glands of “Von Ebner”.

2. The mucous glands:

Made up exclusively of mucin cells: they secrete a viscous saliva, they are the sublingual glands, the accessory glands with the exception of the “Von Ebner” glands.

3. Mixed sero-mucous glands:

They are made up of serous acini + mucous acini = mixed acini;

The submandibular glands are mixed glands, with a predominance of serous acini, they secrete a stringy saliva.

3. Physiological reminders:
   1. Saliva:

Saliva is a transparent, colorless biological fluid, produced in 92–95% of the major salivary glands.

-Saliva flow: Daily salivary secretion is 750ml/24h.

-Saliva pH: it is neutral between 6.8 and 7.5

-Qualitative analysis reveals:

*A water content of 95%

*5% organic substance (mucin, lysozyme, enzyme) and mineral substance (Na ⁺ , K ⁺ , Ca ⁺⁺ , Cl– ⁾ .

2. Role of saliva:
   • Mechanical: Humidification of the mucous membrane and food.
   • Digestive: Solubilization of ingested substances (α-Amylase which transforms sucrose and starch).
   • Detoxification: Elimination of urea, ammonium salts and medications.
   • Bacteriostatic: Linked to the presence of mucins and lysozymes.
3. Diagnostic assessment
   1. Anamnesis:

It must be specified:

• The patient’s age and gender.
• duration of the disorders or swelling.

-The calling symptomatology: pain, swelling.

• the existence of dry mouth: abnormal taste of saliva, itchy eyes or dry eyes.

-The date and manner of onset of the pathology, its sudden or progressive nature, unilateral or bilateral, related or not to meals.

• Local and regional history: (mumps, parotitis, radiotherapy, trauma to the region, intervention in the region itself or in a neighboring area, etc.).

-General pathological context: endocrine disorders, various poisonings (alcohol, bismuth), ongoing treatment (psychotropic drugs).

2. Clinical exploration:

• The careful clinical examination encompasses the entire cervicofacial region.
• Dominant symptoms: Swelling, pain.
• Inspection then palpation will be bilateral, exo then endo buccal

1. Exo-oral examination:

-Inspection:

• Asymmetry.
• The topography of the swelling.
• The condition of the skin, its color, fistula.

-Palpation:

• the contours of the glands, characteristics of a swelling (consistency, limits, sensitivity).
• systematic palpation of the lymph node areas.

2. Intraoral examination:

• Inspection: Accessory salivary gland sites: cheeks, floor, lips, and palate.

-Palpation:

• Allows you to feel a foreign body there
• Discharge of pus

3. Examination of saliva, quantitatively and qualitatively by:

• Manual expression of each major gland plus examination of the ostium: Absence of saliva, jet of saliva.
• Appearance of saliva: stringy, viscous or purulent.
• The sugar cube test : it melts in 3 minutes.
• Quality : Measurement of salivary pH (litmus paper) outside of meals:

In case of drought the pH is lower than 6.5.

3. Additional examinations :
   1. Radiological exploration:
4. Shots without preparation:

-allows you to search for:

Lithiasis (a radiopaque salivary stone), calcinosis, calcified lymph nodes.

• Strict profile (The Parotid)
• Panoramic (the Submaxilla)
• Occlusal bite (Sub-lingual)
• Retro-jugal or retro-labial dental film – At the level of the accessory glands :

Their essential indication lies in the search for radiopaque lithiasis.

2. Ultrasound: The ultrasound image allows
   • At least to eliminate tumor processes.
   • Diagnosis of stones above 2 mm in diameter.
   • The study of cervical lymph node areas.

Pathological images can be of two types:

– Hyper-echogenic image (lithiasis, calcified lymph nodes, etc.)

-Hypo-echogenic image (lymph nodes, infections, tumors, etc.)

3. Sialendoscopy or sialoscopy:

Recent technique,

It avoids the injection of contrast and the inevitable irradiation of sialography.

4. Computed tomography (CT):

5 mm slices in axial and coronal incidence.

• Studies the extension of a tumor or cystic process on bone structures,
• it specifies whether the mass (tumor, cyst, etc.) is extra or intra glandular.

5. Magnetic Resonance Imaging (MRI)

It is used mainly in the diagnosis of expansive processes of soft tissues (tumor processes of salivary glands, lymph nodes).

6. Scintigraphy:
   • Performed by IV injection of Tc99
   • Allows to know the functional value of the salivary glands.
   • Provides an image of secretion at rest and after stimulation of secretion.
   • Allows the study of all glands at the same time.
7. Sialography: Or radiography with preparation of a gland, consists of X-ray of a major salivary gland after ductal-parenchymal opacification by ascending route using a water-soluble or liposoluble contrast product.

Liposoluble contrast agents (lipiodol, myodol) provide precise, high-contrast images of the canals and parenchyma.

Technique:

• Catheterization of the canal under contact anesthesia of the ostium
• Injection of contrast product:

Warm product, inject slowly, 2 CC/parotid, 1 CC/sub max.

• Taking a picture.

Sialogram of a normal gland has 2 types of images:

• Ductal images of the main duct and efferent ducts.
• A parenchymal image.

Pathological sialograms:

-Isolated or predominant canal anomalies:

Dilation, Contraction, Interruption.

-Isolated or predominant parenchymal anomalies:

Lipiodol extravasation, lacunar images, amputation images.

-Mixed anomalies: ductal and parenchymal.

2. Biopsy:

-Salivary biopsy is best indicated in conditions of systemic origin: (sarcoidosis, Gougerot Sjogren’s syndrome, etc.)

-It mainly affects the accessory salivary glands, the most accessible site being the inner surface of the lower lip.

-After biopsy of the accessory salivary glands, perform an anatomo-pathological examination.

3. Serology and microbiology:

-Saliva is normally sterile, and any bacterial ( Staphylococcus aureus , and pyogenes, Streptococcus viridan) or viral (paramyxovirus) or specific (tuberculosis and syphilis) contamination is the consequence of an infection of the gland or the duct.

-Diagnosis of mumps, specific infections, etc.

-Interest: therapeutic (antibiogram).

The search for microbial germs in saliva is mainly of therapeutic interest insofar as it allows for directed therapy based on the results of the antibiogram.

Antibiogram: after drainage and collection of pus, allows the treatment to be readjusted.

Introduction to Salivary Gland Pathology

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Introduction to Salivary Gland Pathology