Hypopharynx: anatomy and pathologies

Bernhard Schuknecht Medical Radiological Institute Zurich/CH

European Course in Head and Neck NeuradiologyMarch 25 – 11:20-11:50

COI Disclosure

• no actual or potential conflict of interest regarding this presentation

bschuknecht@mri-roentgen.ch

Pa viewSobotta Becher 2nd ed. U&S 1972

NasopharynxSkull base

soft palate

Oropharynxsoft palate

pharyngo-epiglottic fold

Hypopharynxhyoid/pharyngo-epiglottic fold

cricopharyngeus m.

= part of upper esophageal spincter UES

Anatomical subdivision of the pharynx:naso-, oro-, and hypopharynx

Hypopharynx visceral spaceHarnsberger ED. Diagnostic Imaging Head and neck 2nd edition Amirsys 2011

Visceral space = continuation of suprahyoid pharyngeal mucosal space upper mediastinum

middle layer of deep cervical fascia (ML-DCF)alar fascia separates RPS and danger space, prevertebral fascia

piriform sinus= anterolateral recessesinverted pyramid with base from pharyngoepiglottic fold to inferior tip (PS apex) at level of true cord

posterior wall = continuation of post. oropharyngeal wall, level of hyoid to inf. cricoid cartilage/ cricopharyngeus m.

postcricoid region= anterior wall of lower hypopharynxfrom cricoarytenoid joints to lower edge of cricoid lamina

Hypopharynx 3 subsites:

• aryepiglottic fold anteromedially

• paraglottic space anteriorly

• thyroid cartilage/thyrohyoid membrane lat.

• carotid space laterally

• crico-arytenoid cartilage anteriorly

• post. wall ML-DCF alar + prevertebral fascia

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Hypopharynx :

Anatomic relationship

HHypopharynx :

Anatomic relationship

• aryepiglottic fold anteromedially

• paraglottic space anteriorly

• thyroid cartilage/thyrohyoid membrane lat.

• carotid space laterally

• crico-arytenoid cartilage anteriorly

• post. wall ML-DCF prevertebral fascia

Mucosa: stratified squamous epithelium and lymphocytes

Submucosa: loose stroma contains fat, serous and mucinous glandssubmucosal infiltration clinically undetactable imagingrich lymphatic drainage - nodes,(retropharyngeal

Muscles: inferior constrictor m. - cricopharyngeus muscleinnervation: motor X, sensory IX, communication with Arnolds nerve (X)

Killians triangle- between thyropharyngeal comp. and cricopharyngeus m. diverticulum

Hypopharynx wall:

Zenker diverticulum

Zachmann DieterLooser margrit 24.10.42Zollinger,Walter 8.8.33Auer, Alexander 26.7.1950Baur, Edgar 22.9.40

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Posterior hypopharyngeal saccular mucosal herniation above cricopharyngeal muscle

DD: Killian-Jamieson diverticum = antero-lateral esophageal pouch below cp muscle; rare, smallerEsophageal webs = 1-2mm mucosal filling defect along anterior wall; esophageal strictures - longer

Risks: aspiration pneumonia (30%), diverticulitis, carcinoma (0.3%), perforation

piriform sinus upper aspect of left thyroidlocalized thyroiditis

4th branchial cleft anomaly

3% of head and neck malignancies.SCC: 95% , majority are environmentally related (alcohol, tobacco)

squamous cell: conventionalsquamous cell variant: adeno- and basosquamous, papillary, spindle, verrucous

other: lymphoepithelial like, neuroendocrine (4%) and composite (SCC- neuroendocrine) Ca`s

minor salivary gland tu (adenoidcystic ca )

worst prognosis of all subsites of head and neck neoplasmssurvival poor, < 50% at 3 y after txrecurrence distant metastasis < 2 years

locoregional

Facts: hypopharynx carcinoma Hypopharynx carcinoma

• piriform sinus 60% moderately –poorly differentiated

• postcricoid region 25% usually well differentiated

• posterior wall 15% usually large and exophytic

• prognosis: piriform > posterior wall > postcricoid

• 50-75% malignant adenopathy at presentation, 15-20% contralateral

• 10% synchronic/ 25% metachronic additional 1ary Ca!

Staging of hypopharynx carcinoma

• T1 one subsite , < 2cm

• T2 > one subsite, 2-4cm

• T3: > 4cm or fixation of hemi-larynx

invasion of esophagus

• T4a: invas. thyroid/ cricoid cartilagethyroid gland- central c. soft tissue

• T4b: invas. prevertebral fascia, ICA, mediastinum

N-Staging in HPV- neoplasms

N0 no regional lymph node metastases

N1 single ipsilateral LN 3cm

N2a single ipsilateral LN > 3cm, < 6cm

single < 3cm ENE+

N2b multiple ipsilateral LN < 6cm

N2c bilateral or contralateral LN < 6cm

N3a single > 6cm, ENE –

N3b single ipsi >3cm ENE+, or multiple ENE+ ipsi-/contralat.

LN level-classification in the neck

Level I: superior to hyoidIA: submental, IB: submandibular

Level II: internal jugular -superior to hyoidIIA: anteror to SCM, IIB: medial to SCM

Level III: int. jugular (inferior hyoid-inf. cricoid)midthird vascular chain – SCM

Level IV: internal jug- inf cricoid- supraclavicularlower vascular chain – SCM

Level V: posterior cervical space – supraclavicularVA : above inf. cricoid level VB: below inf. cricoid

Level VI: prelaryngeal: hyoid- jugulum

Level: VII: jugulum -aortic arch+ retropharyngeal, parotid, facial LN

tends to present in an advanced stage !

Hypopharynx carcinoma

Difficulties in early diagnosis due to • underlying anatomy extended growth from pharyngoepiglottic fold- esophagus

• symptoms of early stage (globus, sore throat) gastroesophageal reflux

• depth of piriform sinus difficult to visualize w office based fiberoptic laryngoscopy

• limited accuracy of routine imaging studies such as CT.

Hypopharynx carcinoma: piriform sinusMR more sensitive primary tu location

cartilage invasionrelation of LN to vessels

w 300/ c100

w 1700/ c600

Piriform sinus most common location = 65%

Hypopharynx carcinoma: piriform sinus

Questions:origin,relation to aryepiglottic fold, paraglottic space, extrapharyngeal extensioncartilage: thyroid/ arytenoid/cricoid ?lymph nodes ?

Anterior wall

Hypopharynx carcinoma: piriform sinus

Cartilage signal :Signal T1 low lowSignal T2 ~ signal tumor > signal tumorSignal T1 Gd ~ signal tumor > signal tumor

Cartilage : invasion inflammation

AnteriorT1

Invasion of thyroid cartilage, + central compartment soft tissue

T2

T1gd

cor STIR

T4a

Hypopharynx carcinoma: posterior wall well defined anterior surface

survival

Extension ?oropharynxesophagusextrapharyngealif yes, vessels/ICA? T4bmediastinum –T4b

Prevertebral fasciainfiltration: T4b

Internal carotid artery encasement = T4b

Interruption of :posterior pharynx muscle +retropharyngeal fat line(T2w >>> T1gd)Muscle = longus colli medial

longus capitis lateral

Hypopharynx carcinoma: posterior wall

Prevertebral fascia infiltration ? T4b?

Hypopharynx carcinoma: postcricoidpostcricoid well defined surfacepoorest prognosis 5-year survival = 30%

Tendency for submucosaloften T3: hemilarynx fixation

or T4 a: cricoid cartilage invas.

cricoid cartilage infiltration

Predisposition:Plummer Vinson syndrome= sideropenic dysphagia16% of pats postcricoid ca

Hypopharynx carcinoma: postcricoid

posterior wall well defined!

Infiltration ofTrachea !!

thyroid gland,

upper esophageal sphincter

= T4a

Hypopharynx carcinoma: piriform sinus

HPV associated hypopharynx carcinoma (6% - 16%) OPSCC >70%pats younger, no risk factors

small tumours w large (commonly cystic) LN

29y female

Sahovaler A et al. Survival outcomes in Human papillomavirus–Associated Nonoropharyngeal Squamous Cell Carcinomas. A Systematic Review and Meta-analysis. JAMA Otolaryngol Head Neck Surg. 2020;146(12):1158-1166. doi:10.1001/jamaoto.2020.3382

“In this meta-analysis of 24 studies, HPV was associated with OS in laryngeal and hypopharyngeal locations but not in the oral cavity and the nasopharynx. “

HPV status vs survival outcome in hypopharynx carcinoma ?

improved survival and quality-of-life outcome of pats with HPV+ OPSCC!- true for hypopharynx ? Pre-treatment Posttx : laser resection and RT

Hypopharynx carcinoma:treatment evaluation- morphology /DWI

Vp

Ktrans

high pre-treatment permeability (Ktrans) and Vp are linked to favorable treatment outcomeinverse correlation between Ktrans , Ve and proliferation (KI 67)

Ve

pre-treatment post-laser and RT Perfusion

Permeability and MVD*histo:*CD31 antigen staining

Proliferation /gradinghisto:* ki 67 stainingVe ~ vessel diameter > cell count

Hypopharynx carcinoma:treatment evaluation- DCE perfusion

Layngopharyngectomy, free jejunal flap, neck dissection, RT

cor sag

1st F-up @ 6months, recurrence local + nodal @ 2.5y

(Rouviere‘s lymph node): Pretracheal lymph node Mediastinal lymph node

Therapy: Primary radiochemotherapy

F-up assessment structural + metabolic

Tumour persistence?

other entities : Venous vascular malformation

Hypopharynx = rare locationmost common type of vm

size by valsalva, position

transspatial extension !

phleboliths

delayed Gd uptake (venous)

Hypopharynx external invasion

Anaplastic thyroid carcinoma

Hypopharynx external compression1. osseous 2. vascular : CCA

Imaging algorithm

• MRI: tumor location, extension, DD

cartilage , larynx involvement

prevertebral fascia, ICA, mediastinum affected?

LN involvement ?

local recurrence ?

• CT (critical ill pats) obstructing neoplasm, airway compromise,

noncooperative, MR noncompatible pacemaker

• PET-CT for staging T3, T4;

Tx response ? Recurrence ?

- thank you

Zürich

Please, ask questions !!