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: