Salivary gland tumours Flashcards
What is the incidence of salivary gland neoplasms as a total and for malignant neoplasms?
All: 0.4 - 13.5 cases per 100000
Malignant: 0.4 - 2.6 cases per 100000
What age is the peak incidence of salivary gland tumours?
6th and 7th decade of life.
Average age for benign is 46 and malignant is 47.
What is the sex distribution of salivary gland neoplasms?
Slight female predilection
What sites are most commonly affected by salivary gland tumours?
64 - 80% are in the parotid gland
7 - 11% are in the submandibular gland
1% are in the sublingual gland
9 - 23% in the minor salivary glands (Palate»_space; upper lip)
What causes salivary gland tumours?
Aetiology is mostly unknown, however guesses and unsubstantial evidence ties them to:
Viral Radiation Occupation Lifestyle Hormones Genetix
Which tumours are more common in salivary glands; Benign or malignant?
80% of salivary gland tumours are benign
Where are malignant tumours more likely to be found in salivary glands?
80 - 90% of salivary gland tumours that occur in the tongue, FoM and retromolar areas are malignant
What factors are looked at when trying to diagnose salivary gland tumours?
Initial history: Duration, rate of growth (how rapid), Pain/numbness/asymmetry of facial expression.
Clinical examination: Size of mass, mobility/fixation, trismus, pain on palpation, skin or scalp lesions, detailed facial nerve exam, assess cervical lymph nodes
Imaging: CT, US, CT sialography, MRI, FDG-PET
Biopsy techniques: FNA, Incisional biopsy.
What is looked at with initial history of a salivary gland tumour?
Duration
Rate of growth
Pain, numbness, facial nerve palsy, asymmetry of expression, Prior cancer history.
What factors are considered with clinical examination of a salivary gland tumour?
Size of the mass
Firm/mobility
Trismus
Skin or scalp lesions
Detailed facial nerve examination
Assess cervical lymphadenopathy
What kind of imaging should be considered for salivary gland tumours?
CT
Ultrasound
CT sialography
MRI
FDG-PET
Which salivary gland tumours are benign? Which is the most common?
Pleomorphic adenoma
Warthin’s tumour
Oncocytoma
Pleomorphic adenoma is the most common benign tumour of the salivary gland. (80% of benign tumours)
Which people get pleomorphic adenoma most commonly?
F > M
4th - 6th decades of life
What are the clinical features of pleomorphic adenomas?
Painless, slow growing (years), firm mass
Firm, rubbery on palpation
Parotid (deep or superficial)
Palate (postero-lateral)
What changes on pleomorphic adenoma histology?
It arises mainly from the intercalated duct reserve cells and differentiates into ductal cells and myoepithlial cells.
Pleomorphic structure (myxochondroid stroma with cartilage/bone/adipose tissue)
Encapsulated tumour with many ducts and prominent myxochondroid areas
Ducts surrounded by myoepithelial cells that merge into hyalinized stroma (containing spindled myoepithelial cells)
Why is pleomorphic adenoma known as pleomorphic?
Pleomorphic in its name because it has a variety of architecture. Myxochondroid stroma (cartilage + mucous) can be bone, cartilage, or adipose tissue.
How is a pleomorphic adenoma treated?
Complete excision to try and preserve the facial nerve
What is the prognosis and recurrence rate of pleomorphic adenoma?
Excellent prognosis if completely removed with low recurrence rate.
Rarely though, malignant transformation DOES occur
How common is warthin’s tumour?
2nd most common benign tumour
Who most commonly gets warthin’s tumour?
M>F
5th - 7th decades of life
Associated with smokers
What are the clinical features of warthin’s tumour?
It is often an asymptomatic, slow growing, fluctuant mass
Affects the parotid mostly and is sometimes bilateral
What is another name for warthin’s tumour?
Papillary cystadenoma lymphomatosum
What are the histological features of warthin’s tumour?
It is well circumscribed
It is a mixture of ductal epithelium and lymphoid stroma
Uniform cells in 2 layers surrounding cystic spaces (tall columnar cells lining lumen, cuboidal cells underneath.
How is warthin’s tumour treated?
Complete excision with margin (to preserve the facial nerve)
What is the prognosis of warthin’s tumour?
It has low recurrence
Malignant transformation is reported as rare (less than 0.1%).
What malignant tranformations have been reported with Warthin’s tumour?
Epithelial: SCC
Lymphoid: Malignant lymphoma, non-hodgkin’s type.
Who most commonly gets oncocytoma?
6th to 8th decade of life and seen in Males and Females equally
What are the clinical features of oncocytoma?
Firm, painless, and slow growing
Affects the parotid and the minor salivary glands on the palate
What are the histological features of oncocytoma?
Well-circumscribed tumour
Sheets of large epithelial cells known as oncocytes
Very little stroma
How is oncocytoma treated?
Complete surgical excision with no radiotherapy
What is the prognosis of oncocytoma like?
Local recurrence is uncommon and transformation to oncocytic carcinoma is rare.
What are the most common malignant salivary gland tumours?
Mucoepidermoid carcinoma
Acinic cell carcinoma
Adenoid cystic carcinoma
Polymorphous low-grade adenocarcinoma
What is the most common salivary gland malignant tumour?
Mucoepidermoid carcinoma
Who most commonly gets mucoepidermoid carcinoma?
F > M
4th - 5th decade of life
Most common paediatric salivary gland malignancy.
What are the clinical features of mucoepidermoid carcinoma?
Presentation may vary
Most often present as a firm, fixed, painless mass
Ulceration
Affects the parotid and the palate
What are the histological features of mucoepidermoid carcinoma?
It is an infiltrative tumour in continuity with surface epithelium containing cystic and solid components.
Epithelial component consists of mucous producing cells and epidermoid cells.
Stroma may contain prominent lymphoid cells
No capsule
In low grade cases it is well-circumscribed
How is mucoepidermoid carcinoma treated?
Wide local surgical excision (including neck dissection)
Radiation therapy
What is the prognosis of mucoepidermoid carcinoma?
Poor survival rate: 5 years = 35%, 10 years = 10 - 20%
Who most commonly gets acinic cell carcinoma?
Slight F > M prevalence
2nd - 7th decade with median age of 52. 7th decade is most common.
What percentage of SG neoplasms are acinic cell carcinoma?
18% of malignant SG neoplasms
6.5% of all SG neoplasms
What are the clinical features of acinic cell carcinoma?
It is slow growing, solitary.
Fixation may occur
Facial paralysis occurs in 10% of cases
Occurs in the parotid in 80% of cases
What are the histological features of acinic cell carcinoma?
It is a nonencapsulated tumour
Solid sheets of serous acinar cells (abundant hematoxylic granules, small dark eccentric nuclei, minimal cytological atypia)
How is acinic cell carcinoma treated?
Complete excision with margins (neck dissection)
Adjuvant radiotherapy
What is the prognosis and recurrence rate of acinic cell carcinoma?
Recurrence rate = 35%
Metastases develop in 16 - 25% of people (to the cervical lymph nodes, lung, liver, and brain)
Most patients do not die of the tumour. 5 year survival = 91% and 10 year survival - 67%
Who commonly gets adenoid cell carcinoma?
slight F>M prevalence
5th - 7th decades of life and very uncommon prior to 3rd decade.
What are the clinical features of adenoid cell carcinoma?
Slow growing mass (Often fixed)
Tenderness, pain, and facial nerve palsy can be present.
Ulceration is common
Which salivary glands are most often affected by adenoid cell carcinoma?
~50% in minor salivary glands
What are the histological features of adenoid cell carcinoma?
Classic swiss cheese (cribiform) pattern.
Lobules and islands of tumour cells with multiple small pseudoducts or true ducts.
How is adenoid cell carcinoma treated?
Wide excision with clear margins. (Complicated by perneural invasion)
Adjuvant radiotherapy.
What is the prognosis of adenoid cell carcinoma?
Long term prognosis is poor. Tumour is relentless and usually is fatal.
80 - 95% eventually die of the disease after multiple recurrences locally and metastases.
Who commonly gets polymorphous low-grade adenocarcinoma?
F > M
Second most common intraoral malignant salivary gland tumour.
2nd - 10th decades of life
6th - 8th most common
What are the clinical features of PLGA?
Painless mass/swelling
Bleeding, otalgia, odynophagia, tinnitus, airway obstruction uncommon.
Affects minor salivary glnads most often
60 - 70% occur at the junction of the hard and soft palate
what are the histological features of PLGA?
It is an infiltrative tumour
Polymorphic in architecture: Solid sheets, duct cells, tubules, trabeculae, cribiform structures, and small islands/strands of cells.
What is the treatment and prognosis for PLGA?
Treatment: Complete surgical excision + neck dissection.
Limited utility for radiotherapy an chemotherapy.
Prognosis is excellent: Local recurrence rate = 9 - 17% and regional metastases = 9 - 15%
What is the DDx of mucoepidermoid carcinoma?
DDx benign mucocele but mucoceles are unlikely at that location because benign mucoceles appear posteriorly.
If visible take an OPG to observe for bone invasion. REFER THIS ONE. DO NOT TOUCH.
How can mucous vs serous salivary glands be distinguished?
Mucous salivary glands are white
Serous salivary glands stain purple on H&E
What do secretory ducts look like on histology?
Their lumen can often be seen and a single layer of cuboidal cells surrounds them typically.
What kind of acini do parotid glands have?
Typically seromucous and serous.
Rarely mucous acini are found. The other 2 dominate the histology of these glands.
What are submandibular glands composed of?
Largely composed of seromucous acini. Some mucous acini are present as well.
What are sublingual glands composed of?
Largely mucous tubules and acini
What acini are minor salivary glands typically composed of?
Large proportion of mucous acini and some seromucous acini.
