disclosures parotid gland: no disclosures introduction

ECHNR 2021 1st Cycle Module 2 m.m.dewin@amsterdamumc.nl

Parotid gland:anatomy and spectrum of pathologies

Maartje M.L. de WinHead, neck & neuroradiology

Amsterdam UMC, AMC

ECHNR 20211st Cycle Module 2

DISCLOSURES

No disclosures

RADIOLOGICAL APPROACH

Congenital

ANATOMY

LEARNING OBJECTIVES

Tumors

Inflammation

- Imaging techniques- Epidemiology- Imaging characteristics

Netter

PAROTID GLANDS

Paired, major salivary gland

PAROTID GLANDS

Facial nerve!!

PAROTID GLANDS

parotid glandsuperficial layer deep cervicalfasciamasticator spaceparotid duct (Stensen)parapharyngeal spacecarotid space

PAROTID GLANDS

parotid glandsuperficial layer deep cervicalfasciaparapharyngeal space

-Incidental finding-Incidence 20-30%-Lateral from masseter-Superior to Stensons duct-Separate blood supply and secondary duct

ACCESSORY PAROTID GLANDS

PAROTID SPACE

Within the parotid spaceparotid gland- parotid ducts- branches of the facial nerve- lymph nodes 20- retromandibular vein- external carotid arteryA

PAROTID GLAND and the FACIAL NERVE

Branches of the facial nerve divide the parotid gland in superficial (2/3) and deep lobe (1/3)

PAROTID GLAND and the FACIAL NERVE

SURGERY ON A PAROTID LESIONWhat the surgeon needs to know

Relationship with facial nerve

Not seen on imaging

Predict by facial nerve line

Chung-O Lee at al, 2012

FACIAL NERVE – PAROTID

2 cases of pleiomorphic adenoma

J. Chu et al. AJNR Am J Neuroradiol 2013;34:1643-1648

MRI of the PAROTID SEGMENT nVII

3D-PSIF-DWI with a surface coil.

PAROTID IMAGING

• Ultrasound / US guided FNA• MRI• CT• PET-CT

Pre-auricular swelling- unilateral vs bilateral- age- painfull vs painless

PAROTID IMAGING

• Ultrasound / US guided FNA• MRI• CT• PET-CT

Radiation, poor soft tissue discrimination

Pre-auricular swelling- unilateral vs bilateral- age- painfull vs painless

MRI PROTOCOL (1.5 & 3T)

TSE T1

TSE T2

Post gadolinium: fatsat TSE T1 or 3D T1 (VIBE, eTHRIVE)

(DCE-MRI)

Axial & Coronal

Including skull base / cavernous sinus / mastoids

High resolution, slice thickness 3 mm

MRI SALIVARY GLANDS

PATHOLOGY OF THE PAROTID GLAND

Congenital- 1st branchial cleft cyst- venolymphatic malformation

Tumors- benign- malignant

Parotitis- infection- inflammation

Congenital- 1st branchial cleft cyst- venolymphatic malformation

1st BRANCHIAL CLEFT CYST• Persisting branchial cleft remnants• Rare (8% of branchial remnants)• Recurrent peri-auricular swelling, enlarging after infection• In parotid gland, near pinna & EAC

• Recurrent parotid space abscess or otorrhea without otitis• Majority presents < 10 y but also in adults

1st BRANCHIAL CLEFT CYST

ImagingUltrasound 1st step• Anechoic cystic lesion• Posterior acoustic enhancement

1st BRANCHIAL CLEFT CYSTC

ImagingUltrasound 1st step• Anechoic cystic lesion• Posterior acoustic enhancement

MRI for extension• Unilocular cyst• Sometimes sinus tract • Thickened and enhancing wall when infected

VENOLYMPHATIC MALFORMATION

• Spectrum of venous and lymphatic developmental abnormalities• Spongy soft tissue mass that grows proportionately with patient• in si e with Valsalva, bending over, crying• rapidly after trauma or infection or under hormonal influences• Present at birth• Percutaneous sclerotherapy

ImagingUltrasound 1st step• Compressible• No arterial flow on Doppler

ImagingMRI for extension & exclude high flow • Trans-spatial• Venous

- Flow-voids, phleboliths, enhancement• Lymphatic

- Unilocular or multilocular- Fluid-fluid levels, peripheral & septal enhancement

• Percutaneous sclerotherapy

Tumors- benign- malignant

SET1 SET2 DWI-B1000

SET1 & Gd SET1 & Gd & FS ADC

M62 y, PREAURICULAR SWELLINGTU

M62 y, PREAURICULAR SWELLING

Solid neoplasmSuperficial lobe of the parotid glandBenign characteristics

Most likely diagnosis?

M62 y, PREAURICULAR SWELLING

Solid neoplasmSuperficial lobe of the parotid glandBenign characteristics

Most likely diagnosis?

Pleomorphic adenoma

EPIDEMIOLOGY SG TUMORS

• Rare lesions• 2-6% of all head and neck tumors• 0,5% of all head and neck malignancies

WHO revised classification 2017

Location Incidence % Malignancy

Parotid 70-80% 20%Submandibular 10-15% 50%

Sublingual 5% 80-90%

Minor salivary 5% 50%

EPIDEMIOLOGY PAROTID TUMORS

Benign most common

Pleomorphic adenoma

Warthin (only parotid)

Malignant most common

Mucoepidermoid carcinoma

Adenoid cystic carcinoma

Carcinoma ex-pleomorphic adenoma

PLEOMORPHIC ADENOMA = benign mixed tumor

Epidemiology

70% of all benign tumors

80% in parotid gland

40-50 yrs

F>MHistology:

Cartilage

Myxoid stroma

Myoepithelial cells

PLEOMORPHIC ADENOMA

MRISolitary, unilateralOvoid, lobulatedT2 very hyperintens to intermediateT1 hyperintens if hemorrhagic

Very high ADC valuesDCE contrast retention

chondroid/myxoid matrix vs higher cellularity (myoepithelial cells)

TSE T2

PLEOMORPHIC ADENOMA ON T2

PLEOMORPHIC ADENOMA

What the surgeon needs to know

Extension

Relationship with facial nerve

Total resection very important

M, 66y• resection of deep lobe pleomorphic

adenoma 18 y before. • Multifocal recurrent disease parotid

and parapharyngeal space

RECURRENT PLEOMORPH ADENOMA

PLEOMORPHIC ADENOMAWhy surgery?• 5-10% risk of malignant degeneration • Carcinoma ex pleomorphic adenoma• Risk increases with time

carcinoma ex pleomorphic adenoma 16 years after biopsy-proven pleomorphic adenoma

CASE 2

Incidental finding on brain MRI in 27 year old male

Incidental finding

Deep lobe/PPS

Looks like pleomorphic adenoma

What’s next?

CASE 2

Possible strategies

surgical resection facial nerve!

wait – and – scan • elderly people

• difficult to reach

INCIDENTAL LESION

Possible strategies

wait – and – scan

be sure it’s benign

INCIDENTAL LESION

Possible strategies

wait – and – scan

be sure it’s benign

INCIDENTAL LESION

Possible strategies FNA

Difficult location, sample error (15% non diagnostic)

‘Standard’ imaging (borders, heterogeneity, infiltration)Not discriminative between benign and malignant disease

Multiparametric imagingT1, T2, ce T1 FSDiffusion weighted imagingDynamic Contrast Enhanced Imaging

TUMOR CHARACTERIZATION

Yabuuchi et al 2008, Freling et al 1992

‘Standard’ imaging (borders, heterogeneity, infiltration)Not discriminative between benign and malignant disease

Multiparametric imagingT1, T2, ce T1 FSDiffusion weighted imagingDynamic Contrast Enhanced Imaging

TUMOUR CHARACTERIZATION

T1 & fat sat

T1 & fat sat & Gado

MRI TUMOUR CHARACTERISATION

T1 & fat sat

T1 & fat sat & Gado

TTT1TTTTTTTTTTTTTTTTTTTTTTT &&& f& f& f& f& f& ffff& ff& ffffffffffffffffatatatttatatatatattattaaaaatttaaaaaaaaaaatattataaaaaatataaaattaaaatttattatttaT1TTTTTTTTTTTTTTT

‘Standard’ imaging (borders, heterogeneity, infiltration)

Not discriminative between benign and malignant disease

Multiparametric imagingT1, T2, ce T1 FSFunctional imaging techniquesDiffusion weighted imagingDynamic Contrast Enhanced Imaging

‘Standard’ imaging (borders, heterogeneity, infiltration)

Multiparametric imagingT1, T2, ce T1 FSFunctional imaging techniques• DIFFUSION WEIGHTED IMAGING• DYNAMIC CONTRAST ENHANCED IMAGING

Yabuuchi et al 2008, Lam et al 2014, Couldert et al 2021

DIFFUSION WEIGHTED IMAGING

• High cellularity low ADC– Warthin, lymphoma, carcinoma

• Low cellularity high ADC– Pleiomorphic adenoma,

inflammation, edema

ADC =2,2x10-3 cm2/secpleiomorphic adenoma

ADC = 0,8x10-3 cm2/secWarthin

• High cellularity low ADC– Warthin, lymphoma, carcinoma

• Low cellularity high ADC– Pleiomorphic adenoma,

inflammation, edema

ADC =2,2 cm2/secpleiomorphic adenoma

ADC = 0,8x10-3 cm2/secWarthin

• TSE- DWI preferable to EPI-DWI

• TSE- DWI less distortions

• At least 3 B values (0, 500, 1000 sec/m2)

• ROI to measure ADC

Hirata et al, Medicine 2018

DWI SALIVARY GLANDS

• DWI may differentiate between malignant and benign tissue– Cut-off 1.4x10-3 mm2/sec pleomorphic adenoma vs carcinoma (sens&spec > 90%)

• ADC Warthin resembles malignant tumors

• IVIM for the future

Yabuuchi et al 2008ADC values

DYNAMIC CONTRAST-ENHANCED MRI

• Microvascular characteristics / biomarkers– Blood volume– Blood flow– Permeability– Wash-in & wash-out

Paldino et al, Magn Reson Imaging Clin Am, 2009

DCE ACQUISITION

• Baseline T1 mapping before Gd• Short T1 GE images after iv Gd (0,2mmol/kg; 4mL/s)• Temporal resolution 3-4s• Duration 3-5 min

Lavini & Pieters, Imago 2016

DCE ACQUISITION

• Postprocessing software• ROI selection

– Exclude cystic and hemorrhagic areas

• Visual /non-parametric analysis– Time Intensity Curves (TICs)

• Time to peak• Washout

• Parametric analysis– Pharmacokinetic modeling

Lavini, Imago 2016; Khalifa et al Med Phys 2014

Yabuuchi H. et al. 2003, Hisatomi M. et al. 2007; Espinoza et al 2013, Lavini et al Imago 2016

TIME-INTENSITY CURVES (TIC’s)

Type A: Ascending plateau, no washoutBenign: pleomorphic adenoma

Type B: rapid uptake, high washoutWarthin

Type C: rapid uptake, low washoutMalignant tumor

Not 100% sensitive/specificOverlap in low grade malignancies, Warthin

S. Espinoza et al, Diagnostic and Interventional Imaging 2013

INTERPRETATION ALGORITHMTU

M, 74ypreauricular swelling

PAROTID LESION – DWI & DCEM, 74y, preauricular swelling

ADC = 2,2 cm2/sec DWI DCE

Curve: TTP> 120s, no washout

No diffusion restrictionAscending uptake

Histology: pleiomorphic adenoma

MULTIMODALITY IMAGING

HIST: Mucoepidermoid carcinoma

MULTIMODALITY IMAGING

Do we always need multimodality imaging?

M, 75y

• Smoker• Swelling preauricular

M, 75y

What to do?– MRI with Diffusion &Perfusion– US guided FNA: Warthin tumor

Epidemiology

15% of all benign SG tumors

Parotid only

M:F = 1:1; smoking ++

50-70 yrs.

Bilateral 10-15%

No malignant transformation

No surgery needed!

WARTHIN’s TUMOR = ADENOLYMPHOMA

ImagingT1 & T2 Heterogeneity

Cysts + blood

DWI: low ADC

DCE: wash-out > 30%

FDG-PET: uptake!

FDG-PET

ADCB1000

DIFFERENTIAL WARTHIN’s TUMOR

Single lesion

Pleomorphic adenoma

Low grade ACC

Mucoepithelial carcinoma

Lymphoma

MetastasisTUM

DIFFERENTIAL WARTHIN’s TUMOR

Single lesion Multiple/ bilateral lesionsPleomorphic adenoma Lymphoma

Low grade ACC Lymphadenopathy

Mucoepithelial carcinoma Benign lymphoepithelial cysts (HIV)

Lymphoma

Metastasis

Chronic auto-immune sialoadenitis

ADENOID CYSTIC CARCINOMA

Epidemiology40-70yrs, F>M

Most common high grade salivary gland tumor

MRILow grade: well described

High grade: infiltrative

T2 hyperintens to intermediate

Contrast: homogeneous enhancement

Perineural spread

T1 & fat sat

F, 28yTU

• Preauricular swelling right side since months

• Facial nerve paralysis since 1 week

T1 T1 ctrStylomastoid foramen!

F, 28y

T1 & FS ctr

WHAT THE SURGEON WANTS TO KNOW

• Extension of the lesion• Perineural spread• Surgical options vs chemo & radiation therapy

• Diagnosis

Facial nerve (VII) Trigeminal nerve (V-3)

PERINEURAL SPREAD

IF THE PATIENT IS A CHILD

M, 2yr

IS IT BENIGN?

Bradley et al. 2007 ORL; 69:137-145

Children AdultsIncidence: 3-4 /million/yr 80/million/yr

Parotid

benign 48% 90%

malignant 52% 10%

EPIDEMIOLOGY: AGE MATTERS!

IF THE PATIENT IS A CHILD

M, 3yr

BIOPSY!

Histology:SialoblastomaTU

Parotitis- infection- inflammation

INFLAMMATION

– Acute (unilateral)– Chronic

• obstructive• non-obstructive: autoimmune (bilateral)

INFLAMMATION

– Acute (unilateral)– Chronic

• obstructive• non-obstructive: autoimmune (bilateral)

Start with ultrasoundInfiltration & hyperemiaDilatation of the ductCystic changesCalculi

MRI IN PAROTITIS

MRI salivary glandsChronic autoimmune (selected cases)

MR sialography with ductal involvementChronic obstructive sialadenitis - Sialithiasis- Strictures- Post radiation xerostomie

AUTOIMMUNE PAROTITIS

• Diffuse enhancement of enlarged or atrophied glands• Cystic changes

Top differential• Sjögren = myoepithelial sialadenitis• IgG4 related sialadenitis• Sarcoidosis PA

M. Sjögren

AUTOIMMUNE SIALADENITISPA

M SJÖGREN = MYOEPITHELIAL SIALADENITIS

Autoimmune disease of thesalivary & lacrimal glands

F>>M, 40-60 yrs

Parotid 85%, submandibular 15%

Sicca symptoms

Swelling 60%

risk of lymphoma

MRI: non-obstructive sialectasia, multiple cystic lesions

MR SIALOGRAPHY

Saliva as natural contrastNo cannulationInformation about the salivary gland distal to obstruction

MR SIALOGRAPHYMRI PROTOCOL

TSE T1 ax

TSE T2 ax & cor

T2 3D-CISS/DRIVE

or 2D-single shot FSE axial 0,6mm & MIP

Head coils / Surface coils

Sialogogue (5cc lemon juice)

Patiënt should be hydrated

Calculus

Erdogan et al. Biomed Res Int. 2013

MR SIALOGRAPHY

MR-SIALOGRAPHY

Erdogan et al. Biomed Res Int. 2013PARO

TAKE HOME 1: EPIDEMIOLOGY

• Parotid tumors are rare• Many different histological types• 80% in parotid 80% benign

• Different DDx for children: – Congenital, venous malformation & infantile hemangioma– 50% of parotid tumors malignant

TAKE HOME 2: CHOICE OF IMAGING

• CT not first choice• US + FNA (without MRI)

– Warthin no resection– Superficial, benign on FNA

superficial parotidectomy without MRI– (Acute) Sialadenitis

• MRI – in all other salivary gland neoplasms– selected cases of (chronic) sialadenitis

TAKE HOME 3: MRI

• Standard MRI sequences do not discriminate between malignant and benign neoplasms

• Include DWI with ADC in your standard protocol– Easy, short, no postprocessing– MRI + DWI: high sens & spec– Warthin mimics malignant tumor on DWI (also on FDG-PET)

• DCE Perfusion has additional benefit– Postprocessing needed (also software)

THANK YOU FOR YOUR ATTENTION

m.m.dewin@amsterdamumc.nl

disclosures parotid gland: no disclosures introduction

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