Salivary Gland & Paranasal Sinuses

Question 1

Three major salivary glands

Answer 1

Parotid

Submandibular

Sublingual

Question 2

Parotid gland anatomy

Answer 2

Are the largest of the salivary glands

Located behind the ramus of the mandible and covers the masseter muscle. Fills the space between the ramus and the anterior border of the sternocleidomastoid muscle.

Question 3

Lymphatics of the parotid gland

Answer 3

Contain extensive lymphatic capillary plexus.

Lymphatics drain from laterally on the face, including eyelids, diagonally downward and posteriorly toward the parotid glands. As do the lymphatics from the frontal region of the scalp.

The parotid nodes then drain down along the retromandibular vein to empty into superficial lymphatics and nodes along the outer surface of the sternocleidomastoid muscle and into upper nodes on the deep cervical chain.

Lymphatics from the parietal region of the scalp also drain partly into the parotid nodes in front of the ear and the retro auricular nodes behind the ear before emptying into the upper deep cervical nodes.

Question 4

Epidemiology of salivary gland tumours

Answer 4

Tumours of the salivary glands are rare and represent 3-4% of all cancers.

The parotid is the site with the highest incidence of salivary gland tumours (80-90%) and more than ⅔ are benign.

Tumours of the minor salivary glands represent 2-3% of these but are 65% are malignant.

Submandibular glands represent 10% of all these

Parotid gland tumours in children are much more likely to be malignant.

Malignant neoplasms occur in patients with an average age of 55

Benign tumours occur around age 40

The incidence in both genders is mostly equal with a slight male predominance

Question 5

Etiology of salivary gland tumours

Answer 5

The cause is mostly unknown

Low-dose ionizing radiation in childhood may account for some cases of malignant tumours.

Females with a history of carcinoma in the salivary glands have eight times higher risk of breast cancer although the cause is unknown

Other risk factors may include dental radiographs

Question 6

Clinical presentation salivary gland tumours

Answer 6

Presenting symptoms are localized swelling and pain

Facial palsy

Rapid growth

Question 7

Radiation treatment of salivary gland tumours

Answer 7

Effective in cases of perineural involvement of nerves.

IMRT used sparing dose to the contralateral salivary gland, orbits, and brainstem.

The high-risk area can be treated with 200cGy/# and 180cGy/# can be treated to the surrounding area.

Question 8

Pathology of salivary gland tumours

Answer 8

The most common cell types for malignant tumours are

Adenoid cystic

Mucoepidermoid

Adenocarcinoma

Question 9

T1 stage salivary gland cancer

Answer 9

T1: Describes a small, noninvasive (has not spread) tumour that is 2 cm at its greatest dimension.

Question 10

T2 stage salivary gland cancer

Answer 10

T2: Describes a larger, noninvasive tumour between 2 cm to 4 cm.

Question 11

T3 stage Salivary gland cancer

Answer 11

T3: Describes a tumour that is larger than 4 cm but not larger than 6 cm and has spread beyond the salivary glands but does not affect the seventh nerve, the facial nerve that controls expression, such as smiles or frowns.

Question 12

T4 stage salivary gland cancer

Answer 12

T4a: The tumour has invaded the skin, jawbone, ear canal, and/or facial nerve.

T4b: The tumour has invaded the skull base and/or the nearby bones and/or encases the arteries.

Question 13

N1 stage salivary gland cancer

Answer 13

N1: Cancer has spread to a single lymph node on the same side as the primary tumour, and cancer found in the lymph node is 3 cm or smaller.

Question 14

N2 stage salivary gland cancer

Answer 14

N2: Describes any of these conditions:

N2a: Cancer has spread to a single lymph node on the same side as the primary tumour and is larger than 3 cm but smaller than 6 cm.

N2b: Cancer has spread to more than 1 lymph node on the same side as the primary tumour, and none measures larger than 6 cm.

N2c: Cancer has spread to more than 1 lymph node on either side of the body, and none measures larger than 6 cm.

Question 15

N3 stage salivary gland tumour

Answer 15

N3: Cancer found in the lymph nodes is larger than 6 cm.

Question 16

Clinical presentation of the paranasal sinus cancer

Answer 16

History of sinusitis nasal obstructions and bloody discharge.

Tumours tend to invade the floor of the orbit causing eye displacement

Question 17

Epidemiology of paranasal sinus cancer

Answer 17

Maxillary sinuses represent 80% of all sinus cancers.

2:1 male prevalence

Typical patients are older than 40

Question 18

Etiology paranasal sinus cancer

Answer 18

Adenocarcinoma of the nasal cavity and ethmoid sinus is associated with wood dust exposure

SCC of the maxillary sinus and nasal cavity is associated with chemical agents found in nickel refining and leather tanning.

No association with smoking

Question 19

Anatomy and physiology paranasal sinuses

Answer 19

The maxillary sinus is a pyramid-shaped cavity lined by ciliated epithelium bound by thin bone or membranous partitions.

The rough of the maxillary sinus is the floor of the orbit.

Question 20

Radiation therapy for paranasal sinuses

Answer 20

IMRT allows for more conformal treatment and fewer long term side effects to the organs at risk than traditional methods.

Elective nodal irradiation is delivered to patients with T3/T4 SCC of the maxillary sinus

Standard fractionations:

High-risk PTV: 6600cGy in 220cGy/#

Standard risk PTV: 5400cGy to 6000cGy in 200cGy/#

Radiation can be used pre-op to create an easier resection for larger tumours

Radiation after surgery has the benefit of a full pathological review of all structures at risk.

Question 21

Treatment volumes for paranasal sinus cancer

Answer 21

The nasal cavity, ethmoid sinuses and maxillary sinuses include both halves of the nasal cavity and the ipsilateral maxillary sinus.

Question 22

Pathology of paranasal sinus cancers

Answer 22

SCC

Question 23

T1 stage paranasal sinus

Answer 23

T1: tumour limited to maxillary sinus with no erosion or destruction of bone

Question 24

T2 stage paranasal sinus

Answer 24

T2: tumour causing bone erosion or destruction including extension into the hard palate or middle nasal meatus, except extension to the posterior wall of the maxillary sinus

Question 25

T3 stage paranasal sinuses

Answer 25

T3: tumour invades any of the following:

The bone of the posterior wall of the maxillary sinus

Subcutaneous tissue

Floor or medial wall of the orbit

Ethmoid sinuses

Question 26

T4 stage paranasal sinus

Answer 26

T4a: moderately advanced local disease

Tumour invasive anterior orbital contents, the skin of the cheek, infratemporal fossa, cribriform plate, sphenoid or frontal sinus

T4b: very advanced local disease

Tumour invades the orbital apex, dura, brain, middle cranial fossa, cranial nerves or nasopharynx.

Question 27

N1 stage paranasal sinus

Answer 27

N1: Unilateral metastasis in lymph nodes 6cm or less above the supraclavicular fossa, or unilateral or bilateral, retropharyngeal lymph nodes or less.

Question 28

N2 stage paranasal sinuses

Answer 28

N2: Bilateral metastasis in lymph nodes, <6cm in the greatest dimension above supraclavicular fossa

Question 29

N3 stage paranasal sinuses

Answer 29

lymph node >6cm in greatest dimension