suprahyoid spaces: anatomy and principle pathologies

02/11/2020

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Suprahyoid spaces: anatomy and principle pathologies

Sofie Van Cauter, MD PhD

• Suprahyoid region: from skull base (BOS) to hyoid bone

• Excluding orbit (O), sinunasal cavity (S/N) and oral cavity (OC)

Superficial fascia (between dermis and deep layer): superficial musculo‐aponeurotic system

Deep fascia:Superficial layerMiddle layerDeep layer

Fascial layers cannot be seen on imaging

MULTIPLE SPACES

Courtesy of Dr Jeffrey Hocking, Radiopaedia.org, rID: 43811

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• Pharyngeal mucosal space (oro‐ /nasopharynx)

• Parapharyngeal space (prestyloid parapharyngeal space)

• Carotid space (poststyloid parapharyngeal space)

• Masticator space (infratemporal fossa)

• Parotid space

• Submandibular

• Sublingual

• Buccal

• Retropharyngeal space (proper / danger space)

• Perivertebral space (prevertebral/paraspinal)

MULTIPLE SPACES

5 principal spaces2 posterior midline spaces

ANATOMY: SOME CONSIDERATIONS

Oropharyngeal isthmus:‐ Junction of the hard and soft palate‐ Anterior tonsillar pillars – palatoglossal arches/muscles‐ Line of the circumvallate papillae

PATHOLOGY

INFECTIOUS/INFLAMMATORY

Tonsillitis – Peritonsillar abscess

Odontogenic abscess

(Sialo)adenitis

Retropharyngeal edema/abscess

ONCOLOGY

Nasopharyngeal carcinoma

Tonsillar carcinoma

Lymphoma

Neurogenic tumours

Paraganglioma

Salivary gland tumours

VASCULAR

Jugular vein trombosis

CONGENITAL

First branchial cleft cyst

SPACE SPECIFIC DIFFERENTIAL DIAGNOSIS

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PHARYNGEAL MUCOSAL SPACE

Contents: Mucosa, lymphatic ring, minor salivary glands, constrictor muscles

Extent: skull base to hyoid boneNaso/oropharynx

Importance:Broad pathology (infectious –Inflammatory –Neoplastic)

Displacement: Invades laterally into the parapharyngeal spaceInvades posteriorly in the retropharyngeal space

T(h)ornwald(t) cyst:‐ Pharyngeal mucosal space – nasopharynx‐ Benign midline cyst‐ Developmental (4%): retraction of the notochord‐ P/ infection (rare)

Lymphoid hyperplasia:‐ Pharyngeal mucosal space – nasopharynx‐ Young adults‐ Look at the lingual and palatine tonils‐ DD. Lymphoma – NPC‐ No erosion – Symmetric – Inflammatory septa

Tonsillar abscess:‐ Extent: tonsillar ‐> peritonsillar PPS/SMS‐ Look at lingual/palatine tonils –FOM‐ Airway status!‐ Lemierre syndrome



SCC Nasopharyngeal ca:‐ Large masses versus small‐ Invasion skull base – retro‐obstructive fluid in mastoid‐ Retropharyngeal nodes

SCC Tonsillar ca:‐ Asymmetry in adenoids‐ Nodes in level 2!


Lymphoma:‐ From nodal tissue ( cervical lymph nodes, palatine/ lingual tonsils, adenoi) ‐ Extranodal locations ( orbits, sinonasal region, salivary glands, bones, subarachnoid space)‐ DDx: SCCa

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PARAPHARYNGEAL SPACE

Prestyloid PPS

Contents: Fat, V3 branches, Internal maxillary artery, aspecnding pharyngeal artery, venous plexus

Extent: skull base to hyoid boneConnection to submandibular space inferiorly

Importance:Easily identifiedDisplacement helsp define location of larger SHN lesions


Primary lesions: rare!Salivary gland tumourSchwannomaSecond branchial cleft cyst (atypical location)

Secondary lesions: displacement patterns

Masticator space postermediallyParotid space anteromediallyPharyngeal mucosal space posterolaterallyCarotid space anteriorlyRetropharyngeal space anterolaterally


Case 1: Venolymphatic malformation (courtesy A. Mancuso) Case 2: Schwannoma (J Surg Case Rep, Volume 2020, Issue 3, March 2020)


Courtesy A. MancusoDisplacement from the PMS

Displacemen t from the parotid space

Displacement from the carotid space

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CAROTID SPACE

Poststyloid PPS

Contents: internal carotid artery, internal jugular vein,CN IX, X, XI and XII, sympathetic plexus, lymph nodes

Extent: jugular foramen to aortic arch

Fascia: all three layers

Importance:Conduit skull base to mediastinum

Vascular lesions:Jugular vein trombosis

PseudoaneurysmDissectionFibromuscular dysplasia

Neoplastic lesionsParagangliomasNerve sheet tumours

CAROTID SPACE

Vascular lesions:Jugular vein trombosis

‐ Rare

‐ IV drug abuse, hypercoagulable state, infections or trauma

‐ Lemierre syndrome

‐ CT/MRI: look along the course of the vessels

CAROTID SPACE

Case 2: tonsillitis with IJV thrombosis

Case 1: tonsillitis with IJV thrombosis

CAROTID SPACE

Paragangliomas – glomus tumours Nerve sheet tumours

< 0,5% tumours H&NNeural crest cellsSporadic and familial

Carotid sheet – middle ear

Carotid body paraganglioma – glomus caroticum‐ Near bifurcation‐ Most common (60‐70% of total)

Glomus vagale tumor‐ Associated with n. X.‐ Extremely rare‐ Level C1

MRI: “Salt and pepper” appearanceFlow voids! Intense enhancement

DSA ‐ ocreotide scan

More commonCranial nervesSporadic and familial

CN IX, X (also IH), XI and XII

MRI: Homo‐/heterogenuous enhancement, no flow voids,cystic changes

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CAROTID SPACE

Case 1: Glomus vagale

CAROTID SPACE

Case 2: Glomus caroticum

November 2019 June 2020

CAROTID SPACE

Case 2: Glomus caroticum

CAROTID SPACE

Case 3: Sympathetic chain schwannoma (Arch Otolaryngol Head Neck Surg 2007; 133(7): 662‐667)

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MASTICATOR SPACE

Contents: mandible, TMJ, pterygoid venous plexus, NV3, masticator muscles

Extent: above zygoma to mandible(Temporal fossa <‐> Infratemporal fossa)

Importance:Perineural tumour spreadOdotogenic abscessRhandomyosarcoma

Displacement: Pushes posteromedially into PPS

MASTICATOR SPACE

Contents: mandible, TMJ, pterygoid venous plexus, NV3, masticator muscles

Extent: above zygoma to mandible(Temporal fossa <‐> Infratemporal fossa)

1. Masseter muscle2. Temporal muscle3. Medial pterygoid muscle4. Lateral pterygpid muscle

* Zygomatic arc Temporal fossa1.

1.1. 1.

2. 2.

3.3.

4.4.*

*

4.4.

1.1. 1. 1.

3. 3.

MASTICATOR SPACE

Odontogenic abscess:‐ Tooth 37/38/47/48: find the offending tooth!‐ Thick enhancing fluid collection‐ Mandible! subperiostal abscess. periostal reaction

Perineural tumour spread:‐ SCC skin/oropharyngeal region‐ Thickening and contrast enhancement‐ Foramen ovale ‐> intracranial

Rhabdomyosarcoma:‐ < 20 years old‐ H&N 50% RMS‐ CT: mandibular destruction‐ MRI: heterogenuous lesion ‐ hemorraghe

+ 18MRobson Pediatr Radiol 2010

PAROTID SPACE

Contents: Parotid gland, n.VII, parotid nodes, retromandibular vein, external carotid artery

Extent: Lateral skull base to parotid tail

Importance:First branchial cleft cystParotid infections (obstructive)Parotid space lesions

Displacement: Pushes anteromedially into PPS

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PAROTID SPACE

First brachial cleft cyst:‐ 7% of branchial cleft anomalies‐ Type III: periparotid‐ Well defined cystic mass +/‐ sinus tract

Parotid infections (obstructive):‐ Swelling, edema, contrast enhancement‐ Periparotitis, abscess‐ Ductal obstruction, sialolithiasis

Parotid space lesions:‐ 80% benign – most common pleiomorphic adenoma‐ Benign characteristics (FNAC) vs Agressive (parotidectomy)‐ Multiple lesions: lymphoma, HIV, Sjögren, Whartin‐ Malignant: mucoepidermoid carcinoma, adenoid cystic carcinoma‐ Level 1 and 5 LN!

Case 1

Case 2

Pleiomorphic adenoma

SjogrenAtypical ‐MEC

Adams et al. Insights Imaging 2016

RETROPHARYNGEAL SPACE

Contents: fat, lymph nodes

Extent: Skull base to Th4 – diafragm (danger space)

Importance:Infection conduit to mediastinum (DS)Suppurative lymph nodesAdenopathies

Alar fascia

Danger space

Retropharyngeal space

RETROPHARYNGEAL SPACE

Retropharyngeal edema:‐ Look for cause‐ Edema ⌿ abscess

Suppurative retropharyngeal adenitis:‐ Pediatric ‐ Pharyngitis ‐ tonsillitis‐ NOT a retropharyngeal abscess!!‐ < 3 cm IV AB‐ Airway! Vessels!

Case 1

Case 2

Tumoural adenopathy:‐ Oral cavity/naso/oropharynx‐ SCC – pap thyroid ca – NHL‐ Radiotherapy

PERIVERTEBRAL SPACE

Contents: muscles, phrenic nerve, brachial plexus, vertebral artery, spine

Extent: Skull base to Th4

Importance:Longus colli tendinitis‐ = acute calcific prevertebral tendinitis‐ Hydroxyapatite deposition in longus colli tendon‐ Neck pain , fever, odynophagia, dysphagia‐ Self limited

Paraspinal compartment

Prevertebral compartment

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Conclusion

• Anatomic spaces normal structures and pathology in the neck.

• Pharyngeal mucosal space: broad pathology – look for additional findings (nodes –invasion)

• Parapharyngeal space: displacement patterns

• Carotid space: glomus tumours versus neurogenic tumours

• Masticator space: odontogenic abscess

• Parotid space: lesions 80% benign – try to differentiate between benign and aggressive lesions

• Retropharyngeal space: edema!

• Paravertebral space: longus colli tendinitis

“ Dans les champs de l’observation, le hasard ne favorise ques les esprits préparés”“ Where observation is concerned, chance favours only the prepared mind”

Louis Pasteur

Glomus caroticum Glomus vagale Nerve sheet tumour

Level bifurcation Level C1

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suprahyoid spaces: anatomy and principle pathologies

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