Salivary Tumours

80% BENIGN

80% PAROTID GLAND

80% PLEOMORPHIC ADENOMAS

 

Classification

Benign:

  • Pleomorphic adenoma
    • Mixed salivary tumour
    • Adenolymphoma

Malignant:

  • Primary:
    • Carcinoma
    • Secondary:
      • Direct invasion from skin or from secondarily involved lymph nodes

 

Pleomorphic adenoma

  • 90% occur in parotid
    • Occasionally found in submandibular, sublingual or accessory salivary glands
    • 90% present <50 yrs

Pathology

  • Macroscopic appearance
    • Lobulated
    • Lies with a false capsule of salivary tissue
    • Cut surface – glistening and transluscent
      • Crumbly consistency
      • Microscopic appearance
        • Vary across a spectrum from typical adenoma to frank carcinoma
        • Majority show glandular acini within blue-staining stroma
          • Gives appearance of cartilage but is in fact mucus
  • Appearance of epithelial cells and ‘cartilage’ gave rise to early concept of ‘mixed tumour’

Surgical considerations

  • Treated by enucleation
  • At least 25% recur:
    • Capsule surrounding tumour is false, which itself is incomplete and may contain cancer cells
    • Serial sections show tumour often has ‘amoeboid’ processes – may be left behind
    • Implantation of tumour cells may occur into the wound
    • Slow growing, but cannot be considered benign:
      • Lack of encapsulation
      • Occasional wide infiltration into surrounding tissues
      • Tendency to recur
      • Less differentiated tumours (difficult to distinguish from frank carcinoma) may metastasise to regional lymph nodes and distantly via blood stream

Clinical features

  • Patient presents with slow-growing swelling anywhere within parotid gland
    • Usually lower pole
    • Region of the angle of the jaw
    • Well-defined lump
      • Firm or hard (sometimes cystic)
      • Usually superficial part of gland
        • Occasionally can be in deep prolongation – may project into pharynx
        • Facial nerve never involved, except in frankly malignant tumours
          • Integrity should be confirmed

Treatment

  • Wide excision of tumour and surrounding parotid tissue
    • Careful preservation of fibres of the facial nerve
      • Superficial parotidectomy
      • Where tumour involves other salivary gland, complete excision of gland performed

Prognosis

  • Excellent provided tumour is completely excised
  • Inadequate surgery leads to high rate of recurrences

 

Adenolymphoma (Warthin’s Tumour)

  • Accounts for approx 10% parotid tumours
    • Very rare elsewhere
    • Usually men >50yrs
      • Occasionally bilateral
      • Macroscopically
        • Soft and cystic
        • Microscopically
          • Columnar cells forming papillary fringes, which project into cystic spaces and are supported by a lymphoid stroma
          • Probably arise from salivary duct epithelium
            • Lymphoid tissue originating from lymphoid aggregates present in normal parotid tissue
            • Presence of lymphoid tissue may lead to confusion with lymphoproliferative disorders
            • Prognosis after excision – excellent

 

Carcinoma

Clinical features

  • Usually affects parotid
  • Equal sexy distribution
  • Patients usually >50yrs
  • Tumour hard and infiltrating
  • Clinical diagnosis based on:
    • Rapid growth
    • Pain
    • Involvement of facial nerve
    • Regional lymph nodes
    • Eventually surrounding tissues infiltrated
      • Overlying skin becomes ulcerated
      • Microscopically
        • Mostly adenocarcinomas
        • Rapidly progressive with high incidence of regional lymph node mets

 Treatment

  • Radical parotidectomy with sacrifice of facial nerve
    • Combined if necessary with block dissection of regional lymph nodes
    • Followed by radiotherapy
    • If arises from other salivary glands; wide excision with block dissection of regional lymph nodes if necessary
    • Prognosis not good
      • Especially if arises from submandibular gland

 

Adverse effects

  • Frey's Syndrome:
  • Symptoms
    • Redness and sweating on cheek area adjacent to ear
    • Appearance:
      • Any action that may produce strong salivation
    • Sweating in the region after eating a lemon wedge may be diagnostic

 

  • Treatments
    • Injection of botulinum toxin type A
    • Surgical transaction of the nerve fibres (temporary)
    • Application of ointment containing anticholinergic drug
      • E.g. scopolamine