Neck and Associated structures

Question 1

How would you improve the scanning of small lesions?

Answer 1

• Use light pressure
• Thick layer of gel
• Gel standoff
• Mobilise mass with fingers

Question 2

Describe a thyroglossal duct cyst

Answer 2

A thyroglossal duct cyst is the most common developmental cyst in the neck. It develops from epithelial lined remnants of the embryonic thyroglossal duct. They can appear between the base of the tongue and the suprasternal region, most lying between the hyoid bone and thyroid cartilage. Cyst development and enlargement are in response to repeated local infection and inflammation. They are usually in the midline or slightly off centre and move superiorly with swallowing. Patients usually present with no pain.

Question 3

Describe the U/S appearance of a thyroglossal duct cyst

Answer 3

• Well-circumscribed mass of 2-4cm with variable appearance dependent on level of infection, number of episodes
• Anechoic with posterior enhancement
• Homogeneously hypoechoic with fine internal echoes
• complex with coarse, irregular internal echoes and septae
• Solid with little to no posterior enhancement
• Debris due to viscosity of fluid, infection of haemorrhage

Question 4

Describe a branchial cleft cyst

Answer 4

Most branchial cleft cysts develop from the 2nd branchial cleft. They are typically positioned laterally near the angle of mandible, under the anterior margin of the sternocleidomastoid muscle, superficial to the CCA and IJV. Sinus tracts may occur. Two common presentations are after an URTI or post-traumatic incident.

Question 5

Describe the U/S appearance of a branchial cleft cyst

Answer 5

• unilocular and well defined
• a beak may be seen
• anechoic with posterior enhancement
• diffuse low-level echoes/debris with little posterior enhancement

Question 6

Describe an abscess/cellulitis

Answer 6

• Most common in immuno-suppressed patients
• Maybe as a consequence of suppurative adenopathy, salivary gland infection, dental abscess, post radiotherapy
• Ill-defined irregular collection with thick wall and internal debris
• u/s assisted drainage may be required
• May appear as loss of fascial planes and associated inflammatory cervical lymphadenopathy

Question 7

Describe a laryngocele

Answer 7

• Rare
• Cystic mas/sac in the larynx
• Associated with laryngeal tumours
• Associated with regular forced expiration eg. woodwind player

Question 8

Describe a lymphangioma/cystic hygroma

Answer 8

• Neonates/young children

- Cystic masses with thin internal septae supero-laterally in the neck

Question 9

Describe a dermoid cyst

Answer 9

• rare
• midline, slightly off midline in sublingual or submental region of the neck
• well-circumscribed and echogenic mass

Question 10

Describe a sebaceous cyst

Answer 10

• common in the posterior neck
• well circumscribed with well defined anechoic or low level internal echoes
• posterior enhancement

Question 11

Describe a lipoma

Answer 11

• benign
• encapsulated lesions that are often palpable
• commonly occur int he superficial tissues of the head and neck
• tend to displace adjacent structures rather than infiltrate
• compressible, well-defined and usually elliptical
• hyperechoic mass compared to adjacent muscle
• heterogeneous internal echoes with linear stranding
• no posterior enhancement or shadowing with no significant vascularity

Question 12

List types of masseter muscle pathology

Answer 12

• abscess
• tumour
• haemangioma
• muscle hypertrophy

Question 13

Describe schwannoma and neurofibromas

Answer 13

• hypoechoic
• heterogeneous solid mass with posterior enhancement
• well-defined (benign)
• ill defined can indicate malignant change
• adjacent nerve may be thickened
• schwannomas are normally more vascular than neurofibromas

Question 14

Describe paraganglioma/chemodactomas

Answer 14

• arise from neural crest cells of the vessel walls

Question 15

Describe carotid body tumours

Answer 15

• Rare
• present as a pulsatile, painless mass in the anterior triangle, near the angle of the mandible
• may be bilateral
• associated with other head paragangliomas
• located at the common carotid bifurcation and splays the internal and external carotid arteries

Question 16

Describe the U/S appearance of carotid body tumours

Answer 16

• Well defined
• hypoechoic compared to adjacent structures
• solid
• does not calcify
• variable internal vascularity

Question 17

Describe a carotid artery bulb

Answer 17

• heavily calcified bulb or carotid artery aneurysm
• may be palpable
• often pulsatile

Question 18

Describe the causes of a jugular vein thrombosis

Answer 18

Can occur as a consequence of indwelling pacemakers, central venous lines, trauma, surgery, infection, IVDU, compression by tumour, mediastinal lymphadenopathy

Question 19

Describe the appearance of the a jugular vein thrombosis

Answer 19

Acute= pain, fever, tender, swelling

Chronic- painless, hard mass

Question 20

Describe the ultrasound appearance of a jugular vein appearance

Answer 20

Acute- appears as ill-defined fascial planes with echogenic matter wihitn the vein, non-compressible, no flow with valsalva
Chronic- normal fascial planes, thrombus well-organised and echogenic

Question 21

Why would you get a jugular vein thrombosis?

Answer 21

Inflammatory or infiltrative cervical lymphadenopathy

May be tumour thrombus associated with follicular or anaplastic carcinoma of thyroid

Question 22

Describe the normal appearance of cervical lymph nodes

Answer 22

A normal lymph node is 2-5mm in diameter. Tonsillar lymph nodes are normally larger. Most normal nodes have a flattened, elongated, oval shape with a length:width ratio >2. They are usually hypoechoic with a fatty hilum

Question 23

Describe the appearance of reactive or suspicious lymph nodes.

Answer 23

String of pearls appearance along the jugular vein of enlarged lymph nodes.
Malignant nodes tend to be round with a length:width ratio <1.5. They can be hypo-isoechoic with an obliterated fatty hilum. They can take on features of the primary with variable blood flow. They may have undergone necrosis and appear cystic.

Question 24

What are the salivary glands?

Answer 24

parotid, submandibular and sublingual- they are responsible for a large portion of total saliva

Question 25

Where is the parotid gland?

Answer 25

- Lying in parotid fossa bounded by mandible and masseter muscle anterior and mastoid process, SCM and digastric muscle posteriorly - Superficial and deep lobes by the facial nerve - Superficial lobe may run over the top of the masseter muscle - Deep lobe extends behind the ascending ramus of the mandible - Hard to see on ultrasound - Can have lymph nodes due to late encapsulation

Question 26

Describe the parotid duct

Answer 26

The parotid duct is 5cm in length and runs over the masseter muscle. It pierces the buccinator muscle to open into the mouth. The diameter is 3mm.

Question 27

Where is the sublingual gland?

Answer 27

- Sublingual glands lie anterior to the submandibular gland deep to the mylohyoid muscle - No intraglandular lymph nodes due to early encapsulation

Question 28

Describe the submandibular gland

Answer 28

The submandibular gland is approximately 5cm. It curves along the mylohyoid muscle and runs parallel to the tongue under the mucosa of floor of mouth. It opens into the oral cavity. The duct has a normal diameter of 2-3mm

Question 29

Describe the u/s appearance of the salivary glands

Answer 29

The parotid has a slightly greater echogenicity compared to the submandibular. It is homogeneous with mid-level echoes. Blood vessels may be hypoechoic. Non-dilated ducts are thin echogenic lines within the superficial gland. Intraglandular ducts and short, echogenic lines. Intraparotid nodes are often seen (5mm diameter within echogenic hilum). Facial nerve is not often seen. Retromandibular vein runs close to the parotid glands.

Question 30

What happens after eating when there is a salivary duct obstruction?

Answer 30

A salivary duct obstruction causes the gland to increase in size while eating.

Question 31

Describe the exam technique for the salivary glands

Answer 31

- Imaging deep section of parotid gland is difficult - Visualising posterior belly of digastric muscle ensures all of deep parotid gland is seen - Lower the frequency for better penetration - Neck rotation to help scan deep portion - Most tumours appear to the superficial portion - Scan both sides for symmetry to exclude bilateral disease - Intra-oral imaging to examine the duct ampulla

Question 32

What are the pitfalls of scanning the salivary glands

Answer 32

- Poor visualization of deep parotid gland - Intraparotid node can be confused for a tumour - Difficult to assess origin of large masses - Submandibular calculi can be mimicked by trapped air bubbles - Difficulty to image the duct ampulla - May not be able to see sublingual or minor salivary glands unless enlarged

Question 33

Describe sialosis

Answer 33

Non-tender, recurrent enlargement of the parotid gland Gland hypertrophy and subsequent fatty infiltration Commonly occurs in malnutrition, alcholism, diabetes Enlarged, echogenic gland with fine texture

Question 34

Describe ranula

Answer 34

Mucous retention cyst of the sublingual and minor salivary glands Simple ranula most common Simple ranula may rupture into submandibular space, forming a pseudocyst Diving/plunging ranula- extends below mylohyoid

Question 35

List salivary gland congenital anomalies

Answer 35

Cyst of the 1st branchial cleft present within the parotid gland Lymphangioma Haemangioma

Question 36

List salivary gland tumour

Answer 36

Parotid gland due to anterior, superficial portion of gland Haematoma Fistula Sialocele

Question 37

Describe salivary gland calculi

Answer 37

``` Sialolithiasis within the gland Sialodocholithiasis within the duct Involves submandibular gland Submandibular saliva has greater mucous content than parotid Single or multiple Can be radiopaque ```

Question 38

Describe ductal dilation

Answer 38

When dilated, easily seen May be due to calculi, tumour or stricture Dilated duct >2mm

Question 39

Describe salivary gland tumours

Answer 39

Palpable mass More common in parotid gland Likely benign In submandibular and sublingual glands, greater chance of being malignant Mass in children likely to be malignant Tumour in parotid may be lymph node related Malignant nodes more common than malignant tumours Malignant tumours present as hard mass, facial nerve paralysis and cervical lymphadenopathy Biopsy required

Question 40

Describe benign pleomorphic adenoma

Answer 40

``` Mixed salivary tumour Most common salivary gland tumour Slow-growing, smooth, non-tender Malignant change- rapid growth Hypoechoic, homogeneous mass with lobulated sharply marginated borders ```

Question 41

Describe warthin tumour

Answer 41

Second most common benign tumour of parotid Multiple and bilateral Originates within intraparotid lymph nodes Slow growing Smoot swelling Well-circumscribed hypoechoic mass, may be heterogeneous

Question 42

Describe a primary malignant salivary tumour

Answer 42

Hypoechoic Small, well-circumscribed, some may be ill-defined Larger tumours are heterogeneous due to necrosis and hemorrhage with ill-defined margins Disorganised flow with high resistive spectral trace

Question 43

Describe mucoepidermoid tumour

Answer 43

A Most common malignant salivary tumour Occurs at any change Common in children

Question 44

Describe cylindroma

Answer 44

A Most common malignant tumour of salivary gland Usually affects salivary glands more than parotid Most common in submandibular May infiltrate facial nerve Single, rounded, hypoechoic mass