Pathological classification
- 75% of tumours occur in parotid gland
- 10% of tumours occur in submandibular gland
- 15% of tumours occur in minor salivary glands
Benign
- Pleomorphic adenoma (mixed parotid tumour)
- Adenolymphoma (Warthin's tumours)
- Haemangioma in children
- Lymphangioma in children
Intermediate
- Mucoepidermoid tumours
- Acinic cell carcinoma
- Oncocytoma
Malignant
- Adenoid cystic carcinoma
- Adenocarcinoma
- Squamous cell carcinoma
Clinical features
- Usually present as lump in the parotid region
- Most are slow-growing even if malignant
- Pain is suggestive of malignancy but is not a reliable symptom
- Facial nerve palsy is highly suspicious of a malignant tumour
- Extent of lesion can often be confirmed by CT or MRI scanning
Picture supplied by Vijay Ramachandran, Calicut Medical College, India
- Open biopsy is contraindicated
- Fine needle aspiration cytology may confirm diagnosis
- Has a poor sensitivity but a high specificity
Pleomorphic adenoma
- Accounts for 75% of parotid and 50% submandibular tumours
- Initially described as a 'mixed' tumour
- Believed to have both epithelial and mesothelial elements
- Now appears to arise from ductal myoepithelial cells
- Male : female ratio approximately equal
- May undergo malignant change but risk is small
- Requires excision with 5-10 mm margin as local implantation of cells can lead to recurrence
Picture provided by M H Randhawa, FMH College of Medicine and Dentistry
Picture supplied by Dr T Bombardieri, Italy
Warthin's tumour
- Also known as an adenolymphoma
- Usually occurs in elderly patients
- Male : female ratio is approximately 4:1
- Accounts for 15% of parotid tumours
- 10% of tumours are bilateral
- Rare in other salivary glands
- Do not undergo malignant change
Intermediate salivary tumours
- Acinic cell and mucoepidermoid carcinomas account for 5% of all tumours
- Have low malignant potential
- Do not require radical therapy
- Can be treated similar to benign tumours
Malignant salivary tumours
- Adenoid cystic, adenocarcinomas and squamous cell tumours are rare
- All are usually high grade tumours
- Prognosis is often poor regardless of treatment
- Adenoid cystic tumours have tendency for perineural spread into the brain
- Also develop distant metastases to the lung
- Cannon-ball metastases may be present for years without symptoms
- Overall 5-year survival is approximately 50%
Management of salivary tumours
- All tumours require partial or complete excision of the affected gland
- Enucleation of benign tumours often results in local recurrence
- In the parotid this involves either superficial or total parotidectomy
- In both procedures the facial nerve is preserved
- For malignant salivary tumours consideration should be given to:
- Postoperative radiotherapy
- Neck dissection if evidence of nodal involvement
Complications of salivary gland surgery
- There are several specific complications
- Can be divided into early and late
- Early complications included
- Haemorrhage and haematoma
- Infection
- Skin flap necrosis
- Trismus
- Salivary fistula
- Nerve palsy
- Facial nerve
- Hypoglossal nerve
- Lingual nerve
- Late complications include
- Frey's syndrome
- Hyperaesthesia of local skin
- Cosmetic defect
- Tumour recurrence
Frey's syndrome
- Relatively common complications after parotidectomy
- May occur in up to 50% of patients undergoing superficial parotidectomy
- Involves gustatory sweating of the face and auriculotemporal region
- Due to regeneration of post-ganglionic secretomotor parasympathetic fibres
- Follow path of post-ganglionic sympathetic fibres that supply sweat glands of the face
- Symptoms can be reduced with botulinum toxin
Bibliography
Que Hee C G, Perry C F. Fine-needle aspiration cytology of parotid tumours: is it
useful? Aust NZ J Surg 2001; 71: 345-348.
Sood S, Quraishi M S, Bradley P J. Frey's syndrome and parotid surgery. Clin
Otolaryngol 1998; 23: 291-301.
Vaughan E D. Management of malignant salivary gland tumours. Hosp Med 2001;
62: 400-405.
Yu G Y. Superficial parotidectomy through retrograde facial nerve dissection. J R Coll Surg Ed
2001; 104-107. |