Head and Neck Flashcards
(51 cards)
1
Q
What structures pass through the foramen ovale?
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A
- Otic ganglion (inferior)
- V3 of CN V (mandibular division)
- Accessory meningeal artery
- Lesser petrosal nerve
- Emissary veins
- The foramen ovale’s proximity to the cavernous sinus means that cavernous sinus pathology may cause invasion.
- This could take place through direct extension of a tumour from the orbit, squamous cell carcinoma (SCC) from maxillary sinus or downward extension of intracranial lymphoma.
- There may be perineural spread of adenoid cystic carcinoma.
- Therapeutic treatment provides access to the trigeminal nerve for treatment of neuralgia with radiofrequency rhizotomy or balloon compression.
2
Q
What structures pass through the foramen rotundum?
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A
- V2 of CN V (maxillary division)
- Branch of distal maxillary artery
- Emissary veins
The foramen rotundum connects Meckel’s cave in the middle cranial fossa with the pterygopalatine fossa.
3
Q
What structures pass through the foramen spinosum?
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A
- Middle meningeal artery
- Middle meningeal vein
- Recurrent branch of mandibular nerve (V3)
- Nervus spinosus
- The middle meningeal artery is the largest and the most important artery supplying the meninges.
- Trauma to the branches of the middle meningeal artery results in an extra-dural haematoma.
- Anatomical variations of the foramen spinosum may be noted due to variant origin of the artery.
4
Q
What structures pass through the foramen magnum?
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A
- Medulla oblongata
- Anterior and posterior spinal arteries
- Vertebral arteries
- Accessory nerve (CN XI)
- Main pathological entities include meningioma, cerebral herniation and Chiari malformations.
- On CT, there is reduced or absent cerebrospinal fluid (CSF) at the foramen magnum along with crowding of contents in tonsillar herniation - this is a neurosurgical emergency!
5
Q
What structures pass through the foramen lacerum?
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A
- Artery and nerve of the pterygoid canal
- Meningeal branches of the ascending pharyngeal artery
- Emissary veins
- It may serve as a portal of skull entry for direct extension of nasopharyngeal carcinoma and angiofibroma and perineural spread of adenoid cystic carcinoma.
- The foramen lacerum is a key part of the anatomy for endoscopic endonasal surgery.
6
Q
What structures pass through the jugular foramen?
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A
- CN IX, X and XI
- Internal jugular vein
- Meningeal branches of ascending pharyngeal artery
- Jugular foramen syndrome - Vernet’s syndrome is characterised by paresis of the glossopharyngeal, vagus, accessory (+/- hypoglossal) nerves.
- **Glomus tumour **is the commonest cause!
7
Q
What structures pass through the hypoglossal canal?
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A
- Hypoglossal nerves
- Meningeal branch of ascending pharyngeal artery
- Emissary veins
8
Q
List causes of basilar invagination.
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A
- Congenital
- Rickets
- Paget’s
- Osteogenesis imperfecta
- Cretinism
- Cleidocranial dysostosis
- Bone destruction (tumour or infection)
- Trauma
9
Q
What are the 3 forms of Chiari malformation?
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A
Chiari 1:
* Herniation of the tonsils below foramen magnum
* Frequently isolated finding
* Associated with syringomyelia, Klippel Feil syndrome, occipitalisation of C1 and other C1 anomalies as in this case
* Normal position fourth ventricle
Chiari 2:
* Dysgenesis of hind brain
* Caudally displaced 4th ventricle
* Caudally displaced brainstem
* Tonsillar and vermian herniation through FM
Benign cerebellar ectopia:
* <3 mm no consequence
* 3-5 mm uncertain
* >5 mm symptoms likely
10
Q
What is the classic triad of clinical findings in Klippel-Feil?
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A
- Short neck
- Low hairline
- Limitation of neck motion
Klippel-Feil is associated with:
* Scoliosis (60%)
* Sprengel’s deformity (30%) +/- omovertebral body
* Renal anomalies e.g. horseshoe kidney (35%)
* Hearing impairment (30%)
* Congenital heart disease (14%)
11
Q
What are the findings on this MRI in a patient with known Klippel-Feil who suffers from dizzy spells and divergent nystagmus.
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A
There is fusion of the upper cervical vertebrae into a block and an omovertebral bone is present. The foramen magnum is wide with low position of the posterior fossa contents which protrude inferiorly.
12
Q
What central skull base defect is shown in the image below?
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A
Encephalocoele
Note the following about encephalocoels:
* Extracranial extension of parenchyma or meninges through a defect in the skull
* Occipital (posterior) is most common in patients of European origin and from the USA
* Sincipital (anterior) is more common in patients of Asian origin and may be mistaken for nasal polyps
* Many present before or at birth as facial/nasal/occipital masses
* Nasopharyngeal encephalocoele is difficult to diagnose as often no signs
13
Q
The image below shows an axial CT slice, coronal reconstruction and sagittal slices from a 69-year-old male with 15-20 year history of abnormal left eye which appears to pulsate.
- Describe the image findings.
- What is the diagnosis?
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A
**Neurofibromatosis **
Proptosis of the left globe with absence/hypoplasia of the left sphenoid wing:
* Hypoplasia greater wing of sphenoid is seen in neurofibromatosis type 1 (NF1)
* Enlargement of orbit and middle cranial fossa
* Small ethmoids and maxillary sinus
* Herniation of temporal lobe
* Presents as pulsating exophthalmos
* Cause unknown (no tumour involved)
- Neurofibromatosis type 1 - von Recklinghausen disease accounts for 90% all cases of NF with an incidence 1 in 4000.
- Some 30% show autosomal dominant inheritance.
14
Q
What are the key features associated with NF1?
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A
- Six or more ‘café-au-lait’ spots
- Two or more neurofibromas
- Axillary freckling
- One plexiform neuroma
- Two or more iris Lisch nodules
- Optic glioma
- Typical bone lesions (sphenoid hypoplasia or tibial pseudoarthrosis)
- One or more 1st degree relatives with NF1
Café au lait spots are flat, light brown to dark brown pigmented birthmarks.
15
Q
What are the CT appearances of a meningioma?
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A
- 75% hyperdense
- 25% calcify
- 90% strongly enhance
16
Q
What are the MRI appearances of a meningioma?
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A
- 75% isointense to grey matter on all sequences
- 95% strongly enhance
- Dural tail
- Starburst pattern of enlarged dural feeders
- 25% atypical with cysts, necrosis or haemorrhage
17
Q
What is fibrous dysplasia?
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A
- A condition of unknown pathogenesis where medullary bone is replaced by fibrous tissue
- Diagnosis is often made between 3-15 years
- Monostotic or polyostotic (usually unilateral) and may affect the femur, pelvis, skull, mandible and ribs
18
Q
What conditions are associated with polyostotic fibrous dysplasia?
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A
Endocrine abnormalities:
* Sexual precosity
* Acromegaly
* Cushing’s
* Gynecomastia
* Parathyroid hyperplasia associated endocrine disorders
- Individuals affected by the McCune-Albright syndrome show sexual precocity and skin pigmentation.
- It is seen in 30% of females with the polyostotic form of fibrous dysplasia.
19
Q
What is chordoma?
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A
- Chordoma are uncommon, accounting for only 1% all intracranial tumours.
- They are slow-growing, destructive tumours that are histologically benign, but locally invasive and prone to local recurrence.
- Approximately one-third occur in the clivus (basi sphenoid and basi occiput) and secondarily involve sphenoid and ethmoids spheno-occipital region, mostly in the midline with half occuring in the sacrum.
- This is typically a midline abnormality unlike chondrosarcoma which starts laterally.
- Patients present in middle age with visual disturbance and opthalmoplegia.
20
Q
What are the CT appearances of a chordoma?
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A
- Irregular bone destruction
- Multiple bone densities within (sequestration)
- Isodense with brain
21
Q
What are the MRI appearances of a chordoma?
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A
- Heterogeneous low T1
- Variable high T2
- APC 0.8-1.3
- Moderate to marked enhancement
Differential diagnosis includes:
* Sinus carcinoma
* Plasmacytoma (low signal on T2)
* Chondrosarcoma (centred on the lateral margin of the clivus in petro-occipital fissure)
* Pituitary carcinoma
22
Q
What is the 3rd most common primary bone neoplasm after myeloma and osteosarcoma?
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A
Chondrosarcoma
- Median age of presentation is 45 years
- Twice as common in males
Clinical presentation:
* Cranial nerve palsies from local tumour effect
* Hyperglycaemia (paraneoplastic syndrome)
23
Q
What are the CT appearances of a chondrosarcoma?
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A
Expansile, destructive soft tissue mass with internal calcification (rings, arcs, snowflakes)
24
Q
What are the MRI appearances of a chondrosarcoma?
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A
- Low or intermediate T1
- High T2 (in contrast to most other malignancies at this site)
- APC >2
- Enhancement post-gadolinium
25
What is the diagnosis?
## Footnote
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Paranasal sinus carcinoma
## Footnote
* One of the most common skull base lesions
* Histologically represent **adenocarcinoma** or **squamous cell carcinoma**
* **Aggressive bone erosion** is indicative of aggressive disease (particularly in SCC)
* Computed tomography provides extent of bony destruction
* MRI provides excellent soft tissue characterisation of spread (including intracranially)
26
Craniopharyngiomas classically present in which decades?
## Footnote
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* 1st and 2nd decade (75%)
* 5th decade (25%)
## Footnote
* 3-4% of intracranial neoplasms
* **50% suprasellar tumours in children**
* **Male** predominance
Features:
* Diabetes insipidus
* Growth retardation
* Bi-temporal hemianopia
* Headache
27
What are the MRI appearances of a craniopharyngioma?
## Footnote
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* Marked hyperintense T2
* Hyper/isointense T1
* **Enhancement of the solid elements and the cyst wall**
## Footnote
The appearances on CT are:
* Inhomogeneous mass
* Curvilinear/flocculent/stippled calcification 90%
* Enhancement solid elements and cyst wall
28
What primary tumours commonly metastasise to bone?
## Footnote
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* **Prostate**
* **Breast**
* Kidney
* Thyroid
* **Lung**
## Footnote
**PB-KTL** mnemonic:
* Prostate - blastic/sclerotic (bone growth)
* Breast - mixed pattern
* Kidney, thyroid, lung - lytic (bone destruction)
29
Describe the image findings.
What is the diagnosis?
## Footnote
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* On the left, the middle ear cleft is opacified, but the unpneumatised mastoid appears grossly intact, consistent with **acute otitis media**.
* On the right, the middle ear cleft and mastoid are opacified with **resorption of bone** in the mastoid resulting in cavity formation. This is **coalescent mastoiditis**.
## Footnote
Acute otomastoiditis and coalescent mastoiditis are complications of **untreated or inadequately treated acute otitis media** and occur most commonly in young children.
When acute coalescent mastoiditis is suspected clinically, an **urgent CT scan** is indicated to confirm the diagnosis and identify any extension of the infection outside the petrous bone.
Two separate sequences are recommended for a comprehensive assessment:
* Fine detail axial bone algorithm scan (0.5 mm)
* IV contrast-enhanced scan
30
Describe the image findings.
What is the diagnosis?
## Footnote
6a_017b
A contrast-enhanced axial section through the upper neck, below the mastoid tip, shows that a **subperiosteal abscess** extends down to the neck. The neck abscess is known as a **Bezold's abscess** (note the fluid and central pocket of air). The abscess has resulted from osteolysis at the mastoid tip.
31
Necrotising (malignant) otitis externa is typically seen in which demographic?
## Footnote
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Elderly patients with diabetes
## Footnote
* May develop** facial nerve or other lower cranial nerve palsies**
* Organism - **Pseudomonas aeruginosa**
* **Subtle bony destructive changes** predominantly involving the external auditory canal and inferior aspect of the mastoid
32
What are the types of middle ear cholesteatoma?
## Footnote
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Cholesteatomas arise in two locations:
1. **Pars flaccida** - Start in **Prussak’s space** and extend superiorly into the attic
2. **Pars tensa** - Start in the **posterior tympanic membrane** and are located in the facial recess and sinus tympani
## Footnote
A cholesteatoma (also known as a **keratoma**) consists of **squamous epithelium** trapped within the middle ear, mastoid or other pneumatised part of the petrous temporal bone. The majority (98%) are **acquired** and the remainder **congenital**.
Cholesteatomas produce **osteolytic enzymes that erode bone**, initially
the scutum and then the ossicular chain in the commoner **pars flaccida** type.
The complications of cholesteatoma occur as a result of the associated bone erosion.
33
What are the two main features of cholesteatoma to look for on CT?
## Footnote
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1. **Non-dependent** material in the middle ear cavity
2. Bone erosion
## Footnote
* If the material in the middle ear is **dependent**, the material is likely to be fluid or granulation tissue.
* If the middle ear cavity is completely opacified,** no distinction** may be made between fluid, inflammatory granulation tissue, cholesteatoma or tumour.
34
What MRI sequence is used to help differentiate recurrent cholesteatoma from granulation tissue?
## Footnote
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Non-echo planar imaging (EPI) diffusion weighted imaging (DWI)
## Footnote
Cholesteatoma is of **high signal on combined sequences**, unlike granulation tissue, which is not.
Other conditions to consider in the differential diagnosis include:
* Glomus tumour (paraganglioma)
* Facial nerve schwannoma
* Cholesterol granuloma
35
What is the characteristic MRI finding in cholesterol granuloma?
## Footnote
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* **High signal on T1 due to cholesterol component and methaemoglobin**
* High signal on T2W
* Remain high signal on fat saturated T1W
## Footnote
Cholesterol granulomas, also sometimes called **chocolate cysts** or **blue-domed cysts**, are a special type of middle ear granulation tissue that represent the **most common cystic lesion of the petrous apex**.
36
Glomus tumours of the head and neck are actually are named after the locations they affect.
Name the four glomus tumours.
## Footnote
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1. **Glomus jugulare** - jugular bulb (lower cranial nerve palsy)
2. **Glomus tympanicum** - Jacobson's nerve (branch of CN XII)
3. **Glomus jugulotympanicum** - Arnold's nerve (branch of CN X)
4. **Glomus vagale** - CN X (dysphagia and hoarse voice)
## Footnote
* Predominantly solid, avidly enhancing, soft-tissue lesions with poorly-defined margins
* Flow voids may be prominent within them giving them a classically **'salt and pepper'** appearance on MRI
* **111In-labelled octreotide** is taken up by these lesions because they contain **somatostatin receptors**
37
What are the most common causes of neck masses?
| * Congenital
* Inflammatory and infective
* Neoplasm
## Footnote
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*Congenital:*
* Branchial cleft cysts (benign squamous epithelium-lined cysts)
* Thyroglossal duct cysts
* Haemangioma and lymphangioma (benign neoplasms, usually present in infancy)
*Inflammatory and infective:*
* Pyogenic infection (often dental in origin)
* Tuberculosis
* Salivary gland enlargement due to sialadenitis
* Other causes of lymph node enlargement (e.g. Castleman's disease)
*Neoplasm:*
* **Squamous carcinoma** accounts for 90% of adult H&N neoplasms
* Lymphoma
* Salivary gland tumours, thyroid carcinoma and metastatic disease (rarer)
38
The deep neck spaces are described in relation to which structure?
## Footnote
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Parapharyngeal space (PPS)
39
Name the deep neck spaces.
## Footnote
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The deep neck spaces can be described in relation to the **parapharyngeal space (PPS)**. Directional deviation of the parapharyngeal fat helps localise pathology in these adjacent compartments:
* Submandibular space (SMS)
* Pharyngeal mucosal space (PMS)
* Masticator space (MS)
* Parotid space (PS)
* Carotid space (CS)
* Retropharyngeal space (RPS)
* Perivertebral space (PVS)
40
1. Which deep neck space is outlined?
2. A primary lesion here will displace the parapharyngeal space in which direction?
## Footnote
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1. Pharyngeal mucosal space
2. Laterally
## Footnote
The pharyngeal mucosal space includes:
* Aerodigestive tract mucosa
* Minor salivary glands
* Lymphoid tissue
* Constrictor muscles
41
1. Which deep neck space is outlined?
2. A primary lesion here will displace the parapharyngeal space in which direction?
## Footnote
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1. Masticator space
2. Posteriorly
## Footnote
The masticator space contains muscles of mastication including:
* Masseter
* Temporalis
* Pterygoids
The **foramen ovale**, carrying the mandibular division of the trigeminal nerve (V3) opens into the masticator space.
42
1. Which deep neck space is outlined?
2. A primary lesion here will displace the parapharyngeal space in which direction?
## Footnote
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1. Parotid space
2. Anteromedially
## Footnote
The parotid space contains:
* Parotid gland
* Branches of external carotid artery
* Retromandibular vein
The facial nerve enters from skull base through the **stylomastoid foramen**, and passes through parotid gland as the facial plexus, dividing the parotid into superficial and deep parts. It passes **lateral to the retromandibular vein**.
43
Which deep neck space is outlined?
## Footnote
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Retropharyngeal space
## Footnote
The retropharyngeal space contains:
* Fat
* Medial and lateral retropharyngeal nodal groups (**nodes of Rouviere**) are important sites of drainage for pharyngeal mucosal lesions, and are not palpable or visible clinically.
44
Which deep neck space is outlined?
## Footnote
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Carotid space
## Footnote
The carotid space consists of:
* Carotid artery
* Jugular vein
* Some lymph nodes of the deep cervical chain
* CNs IX-XII
45
Which anatomical boundaries correspond to the 7 cervical neck levels?
## Footnote
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*Level 1: Anterior submental and submandibular nodes*
* Anterior/lateral - Mandibular symphasis and body
* Posterior - Posterior submandibular gland
*Level 2-4: Deep cervical chain nodes*
* Anterior - Visceral space
* Posterior - Posterior margin of SCM muscle
* Divided by lines through **lower border of hyoid bone** and **lower border of circoid cartilage**
*Level 5: Spinal accessory and transverse cervical chain nodes*
* Posterior to SCM muscle
*Level 6: Pre- and paratracheal nodes*
*Level 7: Upper mediastinal nodes*
## Footnote
**Level 6-7 are rarely involved with head and neck tumours!**
Most pathological process of the aerodigestive tract will drain to lymph nodes within the **anterior triangle** (anterior to sternomastoid) and then drain along the lymphatics to the next group. Drainage is almost always **unilateral** on the side of the lesion, **except for midline lesions and tongue/floor of mouth lesions**.
46
When making a diagnosis of branchial cleft cysts, what other differential should be considered, particularly in older patients?
## Footnote
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Necrotic squamous carcinoma
47
What is the diagnosis (arrow)?
## Footnote
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Thyroglossal cyst
## Footnote
* Along the course of the thyroid duct from tongue base
* Usually peri-hyoid in location
* Quite superficial and near the midline
48
What is strongly associated with pharyngeal and hypopharyngeal tumours?
## Footnote
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Alcohol consumption
## Footnote
* Sites with a rich vascular supply (tongue and pharynx) often metastasise earlier than relatively avascular sites (glottic larynx)
* Clinically silent and typically present with large tumours
* Tongue cancer will metastasis to the **inferior neck** (EXCEPTION)
49
What is strongly associated with larynx tumours?
## Footnote
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Smoking
## Footnote
* Present early due to voice change
50
What assessments are made to stage head and neck tumours?
## Footnote
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* Extent of mucosal primary
* Deep and submucosal extension (particularly into adjacent structures)
* Check for vascular encasement of carotid and jugular occlusion
* Assessment of local nodal metastases
* Thyroid cartilage invasion
## Footnote
* Cartilage invasion is important to identify and often precldes radiotherapy as a primary treatment
* Cartilage sclerosis is **suspicious but non-specific**
51
What are the features of metastatic nodal disease?
## Footnote
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* Enlargement: JDG <15 mm and other LNs <10 mm (maximum short axis diameter)
* Nodal shape: **round nodes** are more likely metastatic than oval
* Nodal grouping: a group of 3 or more nodes (> 7-8 mm short axis diameter)
* **Necrosis: best indicator**
* Extracapsular extension: difficult to assess except when advanced
