46.1 Benign Tumours

• Pleomorphic adenoma—most common in parotid, 1% risk of malignant change per year after 10 years

• Warthin (papillary cystadenoma lymphomatosum)—smoking risk factor, 10% bilateral, M:F 5:1

• Monomorphic adenoma—most common is basal cell adenoma

• Oncocytomas—more common in elderly

46.2 Parotid Tumours

• 80% benign

• Most common pleomorphic adenoma

• Investigations

Fine needle aspiration (FNA) ± US guided

– Pros—preop planning and patient counselling

– Cons—most likely treatment is surgical so result does not change plans

CT/MRI

– Pros—deep lobe component can be identified, good for preop planning and counseling; lymph nodes not detected clinically may be identified therefore affecting treatment plan; infiltrative margins may raise possibility of malignancy

– Cons—if no nodes palpable, unlikely to change treatment

46.3 Submandibular Tumours

• 50% benign

• Investigations

FNA ± US guided

– Pros—treatment planning

– Cons—management of non-diagnostic samples; some laboratories require larger cellular volumes to diagnose lymphomas

46.4 Minor Salivary Gland Tumours

• 25% benign

• Can occur within sinuses, nasal cavity, and larynx

• Investigations

Biopsy under local anaesthetic or general anaesthetic

CT/MRI to evaluate the extent of tumour and nodal status

46.5 General Notes on Salivary Gland Malignancy

• Epidemiology

1 to 2/100,000

3 to 4% total head and neck malignancy

25% parotid, 50% SM glands, 75% minor salivary glands

Risk factors include: RT exposure and occupational silica dust (blast furnaces, cement, glass, ceramic, and clay industries) and nitrosamine (rubber and tire industries)

Mucoepidermoid most common (inc. children)

In children 65% tumours are benign, with haemangiomas being the most common

• Presentation

Typically painless neck swelling

CN VII n weakness indicative of malignancy

Malignancy normally >6th decade

Benign tumours normally >4th decade

46.6 Malignant Tumours

• Mucoepidermoid carcinoma—most common malignant tumour, graded: low, medium, high

• Adenoid cystic carcinoma—most common submandibular gland malignancy, increased risk perineural invasion, lung metastases more common than nodal

• Acinic cell carcinoma—low-grade neoplasm, late recurrences even after 30 years

• Adenocarcinoma—classified into low- and high-grade types

• Squamous cell carcinoma—consider lymph node metastases from melanoma, skin

• Carcinoma ex-pleomorphic adenoma—longstanding history of parotid swelling with rapid increase in size, aggressive, 5-year survival 40%

• Salivary duct carcinoma—poor prognosis, 50% present with nodal metastases

• Lymphoma—may require trucut biopsy to diagnose