Salivary gland tumours (and some tumour like lesions) Flashcards
Classification of salivary gland tumours (7)
Epithelial 1) adenomas 2) carcinomas Non-epithelial 3) connective tissue tumours 4) malignant lymphomas 5) secondary tumours 6) unclassified tumours 7) tumour-like lesions
Salivary gland tumours - epidemiology (6)
About 1000 malignant tumours per year
70% are in the parotid gland, 9% submandibular, 1% sublingual
70% are pleomorphic adenomas
90% are benign
Only 20% are in minor glands
Minor gland (intra-oral) tumours are more commonly malignant (50%)
Age and gender distribution of salivary gland tumours (2)
F > M
F 61-70 most affected
Site distribution of salivary tumours in minor glands (5)
Palate 55% Lips 15% (95% in upper lip) Cheek 10% Tongue 10% Other 10%
Types of tumour by site (5)
Major glands -70% pleomorphic adenoma -5% mucoepidermoid carcinoma -5% ad cystic carcinoma -15% other Minor glands -45% pleomorphic adenoma -20% mucoepidermoid carcinoma -10% PLGA -15% ad cystic carcinoma -10% others
How many tumours in major salivary glands are benign? (1)
80%
Types of benign salivary epithelial neoplasms (6)
Pleomorphic adenoma Warthins tumour Basal cell adenoma Ductal papillomas Cystadenoma
What is a pleomorphic adenoma? (7)
Most common salivary gland tumour Parotid most common site Palate next most common Age 30-60 M=F Benign May recur
Histopathology of pleomorphic adenoma (7)
Mixed (pleomorphic) pattern Islands and strands of epithelial cells Ductal structures common Myxoid, mucoid or chondroid stroma Encapsulated -infiltration of tumour into capsule may be seen Often lobular pattern Occasional tumours are solid
What is a Warthin tumour? (5)
About 10% of benign salivary tumours Always parotid gland More common in males (60:40) Sometimes bilateral or multifocal Completely benign
Histopathology of Warthin tumour
Irregular cysts
Lined by onocytic duct epithelium
Stroma composed of lymphoid tissue
Salivary adenomas (4)
Basal cell adenoma
Canalicular adenoma
Cystadenoma
Inverted ductal papilloma
Malignant epithelial neoplasms (carcinomas) (5)
Mucoepidermoid carcinoma Adenoid cystic carcinoma Polymorphous adenocarcinoma Acinic cell carcinoma Carcinoma in pleomorphic adenoma
Mucoepidermoid carcinoma (6)
- Most common malignant salivary tumour
- 20% of minor and 5% of major gland lesions
- Parotid most common site
- Palate, cheek, retromolar
- Seen occasionally in children
- Malignant – about 10% metastasise
Mucoepidermoid carcinoma histopathology (4)
A mixture of mucous cells and epidermoid (squamous cells)
Lesions are usually multicystic
High grade lesions may be solid with few mucous cells
Occasional lesions have many clear cells
Adenoid cystic carcinoma (7)
- Second most common malignant tumour
- 15% of minor and 5% of major gland lesions
- Parotid most common site
- Palate, cheek, sinuses
- Highly malignant
- 75% of patients die within 20 years
- Metastasis via blood stream
Adenoid cystic carcinoma histopathology (2)
Infiltrative tumour - no capsule
-infiltrates through bone, in blood vessels, along nerves
Has a characteristic multicystic or cribiform pattern: ‘Swiss cheese’
Polymorphous adenocarcinoma (5)
• Only found intra-orally
• Usually palate - 70%
• Lips, Cheek 30%
• Third most common intra-oral malignancy
• Usually over 50 years
-often misdiagnosed on incisional biopsies as pleomorphic adenoma or adenoid cystic carcinoma
-need great care with small palatal biopsies
-previously termed ‘low-grade’
-often survival > 90% at 5 years
-metastases in 10-15%
-similar to umcoepidermoid
-can be unpredictable: papillary cystic lesions and cytological atypia may have worse prognosis
Polymorphous adenomacarcinoma histolopathology (8)
- Lobules
- Ductal structures
- Cribriform areas and ‘washed-out’ nuclei
- Papillary cystic pattern
- Single cell filing
- Perineural infiltration typical
- Infiltrative growth
- Bland, monotonous cytology
Acinic cell carcinoma (3)
- About 5% of salivary gland malignancies
- 80% in parotid; 15% in minor glands
- 30% recurrence rate & 15% metastasise
Histological appearance of acinic cell carcinoma (5)
– Solid – Microcystic – papillary cystic – follicular • Lymphoid tissue + germinal centres common
Carcinoma in pleomorphic adenoma (3)
• About 10% of pleomorphic adenomas may
become malignant
• Usually long standing and/or recurrent lesions
• Elderly: 60+
Carcinoma in pleomorphic adenoma - histopathology (3)
May appear to be a typical pleomorphic adenoma
BUT - shows areas of cytological atypia
Some lesions contain other types of carcinoma: adenoid cystic, adenocarcinoma etc.
Tumour-like lesions (7)
• sialadenosis • oncocytosis • necrotising sialometaplasia • salivary gland cysts • chronic sialadenitis of submandibular gland • lymphoepithelial lesions • cystic lymphoid hyperplasia in HIV
