Salivary gland tumours

Question 1

What is the incidence of salivary gland neoplasms as a total and for malignant neoplasms?

Answer 1

All: 0.4 - 13.5 cases per 100000

Malignant: 0.4 - 2.6 cases per 100000

Question 2

What age is the peak incidence of salivary gland tumours?

Answer 2

6th and 7th decade of life.

Average age for benign is 46 and malignant is 47.

Question 3

What is the sex distribution of salivary gland neoplasms?

Answer 3

Slight female predilection

Question 4

What sites are most commonly affected by salivary gland tumours?

Answer 4

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&raquo_space; upper lip)

Question 5

What causes salivary gland tumours?

Answer 5

Aetiology is mostly unknown, however guesses and unsubstantial evidence ties them to:

Viral
Radiation
Occupation
Lifestyle
Hormones
Genetix

Question 6

Which tumours are more common in salivary glands; Benign or malignant?

Answer 6

80% of salivary gland tumours are benign

Question 7

Where are malignant tumours more likely to be found in salivary glands?

Answer 7

80 - 90% of salivary gland tumours that occur in the tongue, FoM and retromolar areas are malignant

Question 8

What factors are looked at when trying to diagnose salivary gland tumours?

Answer 8

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.

Question 9

What is looked at with initial history of a salivary gland tumour?

Answer 9

Duration

Rate of growth

Pain, numbness, facial nerve palsy, asymmetry of expression, Prior cancer history.

Question 10

What factors are considered with clinical examination of a salivary gland tumour?

Answer 10

Size of the mass

Firm/mobility

Trismus

Skin or scalp lesions

Detailed facial nerve examination

Assess cervical lymphadenopathy

Question 11

What kind of imaging should be considered for salivary gland tumours?

Answer 11

CT

Ultrasound

CT sialography

MRI

FDG-PET

Question 12

Which salivary gland tumours are benign? Which is the most common?

Answer 12

Pleomorphic adenoma

Warthin’s tumour

Oncocytoma

Pleomorphic adenoma is the most common benign tumour of the salivary gland. (80% of benign tumours)

Question 13

Which people get pleomorphic adenoma most commonly?

Answer 13

F > M

4th - 6th decades of life

Question 14

What are the clinical features of pleomorphic adenomas?

Answer 14

Painless, slow growing (years), firm mass

Firm, rubbery on palpation

Parotid (deep or superficial)

Palate (postero-lateral)

Question 15

What changes on pleomorphic adenoma histology?

Answer 15

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)

Question 16

Why is pleomorphic adenoma known as pleomorphic?

Answer 16

Pleomorphic in its name because it has a variety of architecture. Myxochondroid stroma (cartilage + mucous) can be bone, cartilage, or adipose tissue.

Question 17

How is a pleomorphic adenoma treated?

Answer 17

Complete excision to try and preserve the facial nerve

Question 18

What is the prognosis and recurrence rate of pleomorphic adenoma?

Answer 18

Excellent prognosis if completely removed with low recurrence rate.

Rarely though, malignant transformation DOES occur

Question 19

How common is warthin’s tumour?

Answer 19

2nd most common benign tumour

Question 20

Who most commonly gets warthin’s tumour?

Answer 20

M>F

5th - 7th decades of life

Associated with smokers

Question 21

What are the clinical features of warthin’s tumour?

Answer 21

It is often an asymptomatic, slow growing, fluctuant mass

Affects the parotid mostly and is sometimes bilateral

Question 22

What is another name for warthin’s tumour?

Answer 22

Papillary cystadenoma lymphomatosum

Question 23

What are the histological features of warthin’s tumour?

Answer 23

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.

Question 24

How is warthin’s tumour treated?

Answer 24

Complete excision with margin (to preserve the facial nerve)

Question 25

What is the prognosis of warthin's tumour?

Answer 25

It has low recurrence Malignant transformation is reported as rare (less than 0.1%).

Question 26

What malignant tranformations have been reported with Warthin's tumour?

Answer 26

Epithelial: SCC Lymphoid: Malignant lymphoma, non-hodgkin's type.

Question 27

Who most commonly gets oncocytoma?

Answer 27

6th to 8th decade of life and seen in Males and Females equally

Question 28

What are the clinical features of oncocytoma?

Answer 28

Firm, painless, and slow growing Affects the parotid and the minor salivary glands on the palate

Question 29

What are the histological features of oncocytoma?

Answer 29

Well-circumscribed tumour Sheets of large epithelial cells known as oncocytes Very little stroma

Question 30

How is oncocytoma treated?

Answer 30

Complete surgical excision with no radiotherapy

Question 31

What is the prognosis of oncocytoma like?

Answer 31

Local recurrence is uncommon and transformation to oncocytic carcinoma is rare.

Question 32

What are the most common malignant salivary gland tumours?

Answer 32

Mucoepidermoid carcinoma Acinic cell carcinoma Adenoid cystic carcinoma Polymorphous low-grade adenocarcinoma

Question 33

What is the most common salivary gland malignant tumour?

Answer 33

Mucoepidermoid carcinoma

Question 34

Who most commonly gets mucoepidermoid carcinoma?

Answer 34

F > M 4th - 5th decade of life Most common paediatric salivary gland malignancy.

Question 35

What are the clinical features of mucoepidermoid carcinoma?

Answer 35

Presentation may vary Most often present as a firm, fixed, painless mass Ulceration Affects the parotid and the palate

Question 36

What are the histological features of mucoepidermoid carcinoma?

Answer 36

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

Question 37

How is mucoepidermoid carcinoma treated?

Answer 37

Wide local surgical excision (including neck dissection) Radiation therapy

Question 38

What is the prognosis of mucoepidermoid carcinoma?

Answer 38

Poor survival rate: 5 years = 35%, 10 years = 10 - 20%

Question 39

Who most commonly gets acinic cell carcinoma?

Answer 39

Slight F > M prevalence 2nd - 7th decade with median age of 52. 7th decade is most common.

Question 40

What percentage of SG neoplasms are acinic cell carcinoma?

Answer 40

18% of malignant SG neoplasms 6.5% of all SG neoplasms

Question 41

What are the clinical features of acinic cell carcinoma?

Answer 41

It is slow growing, solitary. Fixation may occur Facial paralysis occurs in 10% of cases Occurs in the parotid in 80% of cases

Question 42

What are the histological features of acinic cell carcinoma?

Answer 42

It is a nonencapsulated tumour Solid sheets of serous acinar cells (abundant hematoxylic granules, small dark eccentric nuclei, minimal cytological atypia)

Question 43

How is acinic cell carcinoma treated?

Answer 43

Complete excision with margins (neck dissection) Adjuvant radiotherapy

Question 44

What is the prognosis and recurrence rate of acinic cell carcinoma?

Answer 44

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%

Question 45

Who commonly gets adenoid cell carcinoma?

Answer 45

slight F>M prevalence 5th - 7th decades of life and very uncommon prior to 3rd decade.

Question 46

What are the clinical features of adenoid cell carcinoma?

Answer 46

Slow growing mass (Often fixed) Tenderness, pain, and facial nerve palsy can be present. Ulceration is common

Question 47

Which salivary glands are most often affected by adenoid cell carcinoma?

Answer 47

~50% in minor salivary glands

Question 48

What are the histological features of adenoid cell carcinoma?

Answer 48

Classic swiss cheese (cribiform) pattern. Lobules and islands of tumour cells with multiple small pseudoducts or true ducts.

Question 49

How is adenoid cell carcinoma treated?

Answer 49

Wide excision with clear margins. (Complicated by perneural invasion) Adjuvant radiotherapy.

Question 50

What is the prognosis of adenoid cell carcinoma?

Answer 50

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.

Question 51

Who commonly gets polymorphous low-grade adenocarcinoma?

Answer 51

F > M Second most common intraoral malignant salivary gland tumour. 2nd - 10th decades of life 6th - 8th most common

Question 52

What are the clinical features of PLGA?

Answer 52

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

Question 53

what are the histological features of PLGA?

Answer 53

It is an infiltrative tumour Polymorphic in architecture: Solid sheets, duct cells, tubules, trabeculae, cribiform structures, and small islands/strands of cells.

Question 54

What is the treatment and prognosis for PLGA?

Answer 54

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%

Question 55

What is the DDx of mucoepidermoid carcinoma?

Answer 55

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.

Question 56

How can mucous vs serous salivary glands be distinguished?

Answer 56

Mucous salivary glands are white Serous salivary glands stain purple on H&E

Question 57

What do secretory ducts look like on histology?

Answer 57

Their lumen can often be seen and a single layer of cuboidal cells surrounds them typically.

Question 58

What kind of acini do parotid glands have?

Answer 58

Typically seromucous and serous. Rarely mucous acini are found. The other 2 dominate the histology of these glands.

Question 59

What are submandibular glands composed of?

Answer 59

Largely composed of seromucous acini. Some mucous acini are present as well.

Question 60

What are sublingual glands composed of?

Answer 60

Largely mucous tubules and acini

Question 61

What acini are minor salivary glands typically composed of?

Answer 61

Large proportion of mucous acini and some seromucous acini.