Salivary gland

• Salivary glands


  Exocrine glands whose secretion flows into the oral cavity
• Major salivary glands


  • Parotid
  • Submandibular
  • Sublingual
• Minor salivary glands


  • Numerous small glands widely distributed in the mucosa & sub mucosa of the oral cavity
• Salivary glands


  • Parenchyma derived from the oral epithelium consisting of terminal secretary units leading into ducts that open into the oral cavity
  • Connective tissue forms a capsule around the gland and extends into it, containing the blood & lymph vessels and nerves
• Function of salivary glands


  Production of saliva which contains various organic & inorganic substances and helps in mastication, deglutition and digestion of food
• Parotid gland


  • Opens into the oral cavity on the buccal mucosa opposite the maxillary second molar
  • Has pure serous acini
• Submandibular gland


  • Opens at the sublingual area, marked by small papilla at the side of the lingual frenum on the floor of the mouth
  • Mixed gland mainly serous with mucous
• Sublingual gland


  • Lies between the floor of the mouth & the mylohyoid muscles
  • Opens near the submandibular gland
  • Mixed gland mainly mucous with serous
• Minor salivary glands


  • Located beneath the epithelium in all parts of the oral cavity
• Investigative methods for salivary gland lesions

  • Sialometry
  • Sialochemistry
  • Sialography
  • Scintigraphy
  • Sonography
  • Cytology
  • Biopsy
• Classification of salivary gland diseases


  • Obstruction (calculi, cystic)
  • Infection & inflammation (bacterial, viral)
  • Degenerative diseases (radiation, Sjogren's syndrome)
  • Functional disorders
  • Neoplasm
• Sialolithiasis


  Calcified structures that develop within the salivary ductal system
• Sialoliths


  • Arise from deposition of calcium salts around a nidus of debris within the ductal lumen (bacteria, ductal epithelial cell or foreign bodies)
  • 80% form in the submandibular gland due to longer & tortuous duct and thicker/viscous secretion
  • Adult males are mainly affected, usually unilateral
• Symptoms of sialolithiasis

  Pain & swelling of the gland especially at meal time
• Radiographic appearance of sialoliths


  Radio opaque masses along the duct or within the gland, but 40% of parotid and 20% of submandibular stones are not radio opaque
• Treatment of sialolithiasis

  Removing the calculi by manipulation or incision of the duct
• Mucocele


  A common lesion of the oral mucosa due to traumatic incident to the mucosa & the minor salivary gland
• Mucoceles


  • Typically present as soft fluctuant bluish or translucent swelling, most frequently affect children & young adults
  • Caused by traumatic damage to the duct, with mucous pouring into the adjacent connective tissue and forming a cyst-like space filled with mucous (not a true cyst as no epithelial lining)
• Mucus retention cyst


  Develops from obstruction of salivary flow due to a sialolith, with a lining of compressed duct epithelium
• Ranula


  A large mucocele in the lateral aspect of the floor of the mouth arising from a blocked sublingual gland duct, resembling the belly of a frog
• Ranula


  • Soft, fluctuant & bluish, typically painless but may interfere with speech or mastication
  • A deep, 'plunging' ranula can develop if mucus herniates through the mylohyoid muscle and along the fascial planes of the neck
• Acute bacterial sialadenitis


  Inflammation mainly involving the acinoparenchyma of the salivary glands, more often affecting the major glands than the minor glands
• Acute bacterial sialadenitis


  • Caused by retrograde contamination of the salivary ducts and parenchymal tissues by bacteria from the oral cavity, with stasis of salivary flow promoting the infection
  • More common in the parotid gland due to its serous composition lacking bacteriostatic elements, and its anatomical location adjacent to the maxillary second molar
• Treatment of acute sialadenitis/parotitis

  Antibiotics, often requiring a beta-lactamase inhibitor or second generation cephalosporin, potentially with metronidazole or clindamycin to broaden coverage
• Chronic sialadenitis


  Caused by repeated bouts of acute sialadenitis leading to sialectasis, ductal ectasia and progressive acinar destruction with lymphocyte infiltrate
• Mumps


  A glandular viral disease usually affecting the parotid gland, with potential complications including nerve deafness and orchitis
• Necrotizing sialometaplasia


  A benign condition affecting the palate and rarely other sites containing salivary gland, mimicking malignancy clinically and microscopically
• Necrotizing sialometaplasia


  • Develops due to salivary gland ischemia precipitated by local trauma, surgical manipulation or anesthesia, leading to gland infarction and squamous metaplasia of the ducts
• Differential diagnosis of necrotizing sialometaplasia

  • Squamous cell carcinoma
  • Malignant salivary gland neoplasm
  • Syphilitic gummas
  • Deep fungal infection
  • Subacute necrotizing sialoadenitis
• Salivary gland tumors


  The next most common neoplasms of the mouth after squamous cell carcinoma, with 75% being benign
• Etiology of salivary gland tumors

  Unknown, but can result from irradiation to the head area
• WHO classification of salivary gland tumors

  • Epithelial tumors (adenomas, carcinomas)
  • Non-epithelial tumors (lymphoma, sarcoma)
• Pleomorphic adenoma


  The most common salivary gland tumor, a benign neoplasm thought to arise from myoepithelial cells or duct epithelium
• Pleomorphic adenoma


  • Typically presents as a painless, slowly growing mass, most commonly in the parotid gland but also in the palate, upper lip and other intraoral sites
  • Histologically shows a great variation with cuboidal cells, squamous cells, myxoid material, cartilage and bone
• Treatment of pleomorphic adenoma

  Wide excision, with removal of the involved lobe in the parotid gland due to high recurrence risk
• Monomorphic adenomas


  A group of benign salivary gland tumors with a more uniform histological pattern than pleomorphic adenoma, including Warthin's tumor, oncocytoma, basal cell adenoma and canalicular adenoma
• Warthin's tumor


  A benign neoplasm of the parotid gland, accounting for 9% of parotid tumors, with uncertain pathogenesis potentially involving heterotopic salivary gland tissue in lymph nodes
• Benign pleomorphic adenoma


  May undergo malignant changes either to a carcinoma, adenocarcinoma or cylindroma
• Monomorphic adenomas


  Lesion consisting of a group of benign salivary gland tumors which have a uniform histopathological pattern than the common pleomorphic adenoma
• Variety of tumors included under monomorphic adenoma

  • Warthin's tumor
  • Oncocytoma
  • Basal cell adenoma
  • Canalicular adenoma