6. Head and Neck p334-344 (Soft Tissue Neck)

Question 1

Parotid space (6)

Answer 1

Basically the parotid gland and portions of the facial nerve.
Can’t see facial nerve, but can see the retromandibular vein which runs medial to the facial nerve.
Parotid is the only saliary gland to have lymph nodes, so pathology of the gland itself or lymph nodes is possible.
Contains
- Parotid gland
- Facial nerve
- Retromandibular vein

Question 2

Pleomorphic adenoma (4)

Answer 2

Most common major (and minor) salivary gland tumour. Most commonly occurs in the parotid (can occur in submandubilar or sublingual glands).
90% occur in the superficial lobe.
Commonly T2 bright with rim of low signal.
Small malignant potential and are treated surgically.

Question 3

Superficial vs deep pleomorphic adenoma (4)

Answer 3

Involvement of the superficial (lateral to the facial nerve) or deep (medial to the facial nerve) is important for surgical approach.
Line is drawn connecting the lateral surface of posterior belly of digastric muscle, with the lateral surface of the mandibular ascending ramus, to separate superficial from deep.
Can spill and reoccur if not removed properly.

Question 4

Warthins tumour (3)

Answer 4

Second commonest benign tumour, only occurs in the parotid gland.
Usually cystic, in a male, 15% bilateral, associated with smoking.
Takes up pertechnate, and is basically the only parotid tumour to do so.

Question 5

Mucoepidermoid carcinoma (4)

Answer 5

Most common malignant tumour of the minor salivary glands.
Smaller the gland, the more common the malignant tumours and the bigger the gland, the more common the benign tumours.
Variable appearance based on histologic grade.
Associated with radiation

Question 6

Adenoid cystic carcinoma (2)

Answer 6

Malignant salivary gland tumour, favours minor glands but can affect the parotid.
Common for perineural spread.

Question 7

Lymphoma (4)

Answer 7

Can get primary or secondary. Only occurs in the parotid because it’s the only salivary gland with lymph nodes.
If bilateral, think Sjogrens.
Sjogrens have massively elevated risk of parotid lymphoma.
Appearance is variable, like other lymphomas.

Question 8

Acute parotitis (5)

Answer 8

Obstruction of flow of secretions is commonest cause.
Likely due to stone in Stensen’s duct, which will become dilated.
Stones are calcium phsophate.
Post infectious parotitis is usually bacterial.
Mumps is commonest viral cause.
Sialography is contraindicated in the acute setting.

Question 9

Benign lymphoepithelial disease (3)

Answer 9

Bilateral mixed solid and cystic lesions with diffusely enlarged parotid glands.
Seen in HIV
Painless, unlike parotitis.

Question 10

Sjogrens (5)

Answer 10

Autoimmune lymphocyte induced destruction of the gland.
“Dry eyes and dry mouth”
Typically women in their 60s.
Hugely (1000x) increased risk of non-hodgkins MALT type lymphoma.
Honeycombed appearance of the gland.

Question 11

Carotid space (4)

Answer 11

Contains:
- Carotid artery
- Jugular vein
- Portions of CN 9, 10, 11
- Internal jugular chain lymph nodes.

Question 12

Carotid space tumours - DDx (4)

Answer 12

Paraganglioma
Schwannoma
Neurofibroma
Lymph nodes: mets from SCC frequently affect this area

Question 13

Paragangliomas (7)

Answer 13

3 different types, based on location, with similar imaging features.
Hypervascular (intense tumour blush) with salt and pepper appearance on MRI from heterogeneity and flow voids.
Can be multiple or bilateral in familial conditions.
111In Octreotide accumulates in these tumours
Locations/types:
Carotid body tumour - at the carotid bifurcation, splaying the ICA and ECA
Glomus vagale - above carotid bifurccation, below jugular foramen.
Glomus jugulare - skull base, often destroys jugular foramen and/or middle ear
Glomus tympanicum - confined to middle ear. “overlying the cochlear promontory. Middle ear is intact

Question 14

Schwannoma (5)

Answer 14

Can involve 9th, 10th, 11th and even 12th cranial nerves.
Not very vascular (unlike paraganglioma)
No salt and pepper on MRI (unlike paraganglioma)
Not 111In-octreotide avid (unlike paraganglioma)
No flow voids (unlike paraganglioma)

Question 15

Lemierre syndrome (4)

Answer 15

Thrombophlebitis of the jugular veins with distant metastatic sepsis, usually septic emboli in the lung.
Found in setting of oropharyngeal infection (pharyngitis, tonsillitis, Peritonsillar abscess) or recent ENT surgery
Caused by Fusibacterium Necrophorum

Question 16

Masticator space (3)

Answer 16

Contains muscles of mastication (masticator, temporalis, medial and lateral pterygoids)
Angle and ramus of mandible and inferior alveolar nerve.
This space extends superiorly along the side of the skull, via temporalis muscle. Aggressive neoplasm or infection may ride up here

Question 17

Odontogenic infection (3)

Answer 17

Most common cause of masticator space mass in adult.
Should look at mandible on bone windows next.
Look for spread via pterygopalatine fossa to orbital apex and cavernous sinus.

Question 18

Sarcomas (2)

Answer 18

Can get rhabdomyosarcomas in the masticator space in kids.
Also sarcomas from the mandible (chondrosarcoma favours the TMJ)

Question 19

Cavernous haemangiomas (3)

Answer 19

Identified by presence of phleboliths.
Venous or lymphatic malformations may involve multiple compartments/spaces.
Congenital pathology and aggressive infection/cancer tends to be trans-spacial.

Question 20

Perineural spread (3)

Answer 20

Spread from head and neck primary along the 5th cranial nerve.
Occurs classically in:
- adenoid cystic minor salivary tumours
- melanoma

Question 21

Nerve sheath tumours (2)

Answer 21

Schwannoma or neurofibroma of V3 in the masticator space.
Schwannoma is more likely to cause foramina expansion vs perineural tumour spread.

Question 22

Retropharyngeal space/danger space (3)

Answer 22

Behind the middle layer of the deep cervical fascia, but anterior to the alar fascia.
Danger space is actually just posterior to the “true” retropharyngeal space, behind the layer of alar fascia.
It’s a potential space, can’t see unless it’s distended.
Infection in the danger space tracts down into the mediastinum, so pus (or cancer) can get right into the mediastinum.

Question 23

Retropharyngeal space/danger space infection (3)

Answer 23

Involvement of the retropharyngeal space most often occurs from spread from the tonsillar tissue.
Enhancing soft tissue and stranding in the space.
Should evaluate for spread of infection into the mediastinum.

Question 24

Necrotic nodes/squamous cell mets in the retropharyngeal/danger space (3)

Answer 24

SCC mets or suppurative infection to the lateral retropharyngeal nodes of Rouviere.
Papillary thyroid cancer can also met here.
Lymphoma can involve these nodes, but won’t be necrotic until treated.

Question 25

Grisel's syndrome (2)

Answer 25

Torticollis with atlanto-axial joint inflammation, seen in H&N surgery or retropharyngeal abscess

Question 26

Parapharyngeal space (8)

Answer 26

Primerily a ball of fat with a few branches of the trigeminal nerves, and pterygoid veins. Mets and infections can directly spread into this space (SCC from tonsils, tongue, larynx). Cancer and infection can spread rapidly in a vertical direction through this fat. Bordered on 4 sides by different spaces - Carotid space displaces anteriorly - Parotid space displaces medially - Masticator space displaces posteriomedially - Superficial mucosal space displaces lateraly

Question 27

Lymph node anatomy - trivia (levels) (5)

Answer 27

Anterior belly of digastric separates 1A from 1B. Stylohyoid muscle (posterior submandibular gland) separates 1b from 2A. Spinal accessory nerve (Jugular) separates 2A from 2B. Vertical borders: - 2-3 = lower hyoid - 3-4 = lower cricoid

Question 28

Floor of mouth SCC (2)

Answer 28

Classically smoker/drinker if old, HPV if young. Necrotic level 2 nodes can be a presentation.

Question 29

Nasopharyngeal SCC (5)

Answer 29

More common in asians and has bimodal distribution (age 15-30, and age >40). Involvement of parapharyngeal space results in worse prognosis (compared to nasal cavity or oropharynx invasion). Most common location is the Fossa of Rosenmuller (FOR). If you see unilateral mastoid effusion or pathological retropharyngeal node, look in FOR. Earliest sign of nasopharyngeal SCC is the effacement of fat within the FOR. If you see a supraclavicular node, look closely at the bones for mets, especially clivus.

Question 30

Laryngeal SCC (3)

Answer 30

Role of radiology here is staging rather than primary diagnois. Subdivided into supraglottic, glottic and infraglottic. Transglottic would refer to an aggressive cancer that crosses the laryngeal ventricle.

Question 31

Laryngeal SCC trivia (6)

Answer 31

Glottic SCC has best outcome (least lymphatics) and most common. Subglottic is least common, can be clinically silent until nodes involved. Subglottic tumours are often small compared to nodal burden. Fixation of the cords indicates at least T3 tumour. Only reliable sign of cricoid invasion is tumour on both sides of the cartilage (irregular sclerotic cartilage can be normal). Invasion of the cricoid cartilage is a contraindication to all types of laryngeal conservation surgery (cricoid cartilage is necessary from post op stability of the vocal cords). Paraglottic space involvement makes the tumour T3 and "transglottic". Best seen in coronals.

Question 32

Laryngocele (3)

Answer 32

Laryngeal saccule dilates with fluid or air. Dilated because of obstruction. 15% of obstructions are due to tumours.

Question 33

Vocal cord paralysis (2)

Answer 33

Affected side will have an expanded ventricle (the opposite side with cancer). If seen on the left, next step is to look for recurrent laryngeal nerve involvement at the AP window.