Parotid Neoplasm

Parotid Neoplasms

Presenter : Dr. Kuotho T Nyuwi

Moderator: Dr. Ak Ibohal Singh

Salivary Glands

Three major

- Parotid

- Submandibular

- Sublingual

Many minor~450

Function – Mastication(lubrication)

Inhibits bacterial growth

Digestive enzymes

The Parotid Gland

ANATOMY

Largest

Pyramidal shape

Wt – 25gms

Situated below

the acoustic

meatus and

in between the ramus

of the mandible and sternomastoid muscle.

Resembles inverted 3 sided pyramid

Four surfaces

- Superior /base

- Superficial

- Anteromedial

- Posteromedial

Borders

- Anterior

- Posterior

- medial

Arbitrary division – by facial nerve

Superficial part – 80%

Deep part – 20%.

Accessory parotid Gland (Socia parotidis)

- Anterior to the superficial

lobe on the masseter

muscle

Boundaries:

Ant – Masseter Muscle

Mandibular Ramus

Sup – Ext. Acoustic meatus

Condyle of the Mandible

Post - Mastoid process

Sternocleidomastoid muscle

Inf - Post. Belly of digastric

Med – Styloid process

Parotid capsule:

Derived from investing layer of deep cervical fascia

Superficial layer – Thick & closely adherent.

Sends fibrous septa into the gland

Deep Layer – Thin, Attached to styloid process,

mandible and tympanic plate.

Parotid Duct (Ductus parotideus/ Stensen’s duct)

5cm in length

Appears at the ant. border of the gland

Runs ant. & downward on the masseter

At the ant. border of the masseter it pierces –

- Buccal pad of fat

- Buccopharyngeal fascia

- Buccinator Muscle

Opens opposite to the crown of 2nd upper molar tooth

Structures within the parotid gland

- Facial Nerve

- Retromandibular vein

- External carotid artery

Facial nerve(Radiates like goose foot- pes anserinus)

Emerges from the stylomastoid foramen

Pierces the posteromedial surface

Lies superficial to the ext. carotid artery & retro

mandibular vein

Divides into:

1. Temporo-zygomatic trunk – Temporal

Zygomatic

2. Cervico facial trunk – Buccal

Marginal Mandibular

Cervical

Blood supply:

Arterial – Maxillary and Sup. temporal artery

(Branches of ext. carotid)

Veins – Retromandibular vein Ext.Juglar vein

Nerve supply :

Sensory – Auriculotemporal N.

Parasympathetic – Secretomotor

Via auriculotemporal N

sympathetic – Vasomotor

Ext. carotid plexus.

Lymphatic drainage

Intraglandular

Parotid lymph gland

Extraglandular (preauricular &

Infraauricular)

Deep cervical lymph glands

Parotid Neoplasm

Most common site for salivary tumors

Mostly in the superficial lobe

- Slow growing, painless swelling

below the ear, in front of the

ear or in the upper aspect of the neck

May arise from accessory lobe

Deep lobe - Parapharyngeal mass

80% of salivary neoplasm occur in parotid gland

80-90% are benign (commonest – Pleomorphic Adenoma)

90% minor salivary gland tumor are malignant

Incidence of malignancy – inversely related to size of gland

Parotid ~ 20%

Submandibular ~ 40%

Sublingual ~ 60%

Minor glands ~ 80%

Aetiology

Radiation

Smoking (Warthin’s tumor)

Genetics – loss of alleles of chromosomes in

12q, 8q, 17q

Environment & diet – Def. of vit A, industrial agents like nickel,

cadmium, hair dyes, silica, preservatives

Infective – Mumps, EBV, chronic sailadenitis

Recurrent inflammation dysplasia carcinoma

ClassificationA) Epithelial (90%)

1) Adenomas

Pleomorphic adenoma

Monomorphic adenoma(Adenolymphoma)

2) Carcinomas

Mucoepidermoid carcinoma ( most common)

Acinic cell Ca.

Adenoid cystic Ca.

Adenocarcinoma

Sq. cell Ca.

Ca. in ex pleomorphic adenoma

B) Non epithelialHaemangioma

Lymphangioma

Neurofibromas

C) Malignant lymphomas

Primary – NHL

Secondary – Lymphoma in Sjogren’s syd

D) Secondary tumors

Local – Head and neck

Distant - Skin and bronchus

E) Unclassified tumors

F) Tumor like lesion

Solid lesion – Benign lymphoepithelial lesion

Adenomatoid hyperplasia

Cystic lesion – Salivary gland cyst.

Benign tumors

- Painless

- Slow growing

- No facial nerve involvement

Pleomorphic Adenoma

- Commonest (80%)

Parotid – 80%

Submandibular – 10%

Sublingual – 0.5%

- Histologically – Epithelial cells

Myoepithelial cells

Mucoid materials

Cartilages/pseudocartilages

- Grossly – Solid tissues

Cartilages

Cystic spaces

Diagnosis

- Usually unilateral

- Firm lobulated, mobile, painless swelling

- Not adherent to skin/ masseter muscle

- Positive curtain sign

Malignant transformation (3-5%)

- Recent increase in size

- Pain

- Involvement of skin, ulceration

- Involvement of masseter

- Involvement of the facial nerve

- Involvement of neck nodes

- Restriction of jaw movement

Pain is usually due to

Capsular distension by tumor

Obstruction to free flow of saliva

Nerve infiltration

Inflammation like in Warthin’s

Tumor necrosis

Investigations

FNAC – 95% accuracy

CT Scan – Status of deep lobe

Local extension

Spread

MRI

Open Biopsy – Contraindicated

- Chance of injury to facial nerve

- Chance of parotid fistula formation

- Seeding of tumor cells and high chance of recurrence

Treatment

Superficial parotidectomy

Total conservative parotidectomy

RT can be given

Recurrence(5%)

Spillage

Improper technique

Inadequate margin

Retained pseudopods

Multicentricity

Adenolymphoma

- Warthin’s Tumor/ Papillary Cystadenolymphomatosum

- Misnomer – Neither malignant nor Lymphoma

- 5-15% of Parotid tumor (2nd most common tumor)

- Smoking – 8 times more risk

- Mostly in the lower pole & overlies the angle of mandible

- Usually involve only the superficial lobe

- More common in male, elderly and in whites

- No malignant transformation

Microscopy –:

- Cystic/Glandular spaces

- Lined by columnar epithelium

- Abundant lymphoid tissue in the stoma

Investigations:

- FNAC

- Tc99 scan – Hot spot (due to high mitochondrial

content)

Treatment:

- Superficial parotidectomy

Oncocytoma

- < 1% of salivary gland tumor

- Mostly in parotid glands

- Gross: Small tan colored well circumscribed encapsulated

solid tumor

- Microscopy: Large oncocytes with swollen granular

cytoplasm

- Hot spot on Tc99

Malignant tumors

Mucoepidermoid Ca.

- Most common malignant tumor of the parotid

- Occurs both in minor & major glands

- Slow growing attaining large size

- High grade – Epidermoid cells mainly –regional & distant

spread

- Low grade – Mucous cells mainly – regional nodes spread.

Adenoid Cystic Carcinoma

- Rare in parotid gland

- Also called cylidromatous Ca.

- Slow growing but highly malignant

- High affinity for perineural spread(trigeminal ganglion)

- Blood spread – Lungs, Bones, Liver

- Treatment : Radical Parotidectomy

RT

- 5year survival – 70%

Acinic cell tumor

- Mainly in parotid gland

- Low grade malignant tumor

- 3% of salivary glad tumor, 90% in parotid

- Can involve facial nerve or neck nodes

- Mets to lungs and vertebra

- 5 year survival – 85%

Malignant Mixed tumor

- Worst prognosis

- Types:

- Ca. ex pleomorphic adenoma (commonest)

Most aggressive tumor

Radical Parotidectomy

- Primary Malignant mixed tumor

- Metastasizing mixed tumors

- 5years survival - <50%

Squamous cell Ca

- Rare

- High grade

- Common in 6th-7th decade

- Rapidly growing, pain, facial palsy, skin fixity, ulceration

- Poor prognosis

- Radical parotidectomy and RT

TNM staging of malignant salivary tumors (AJCC 7th edition)

Primary tumor (T)

TX Primary tumor cannot be assessed

T0 No evidence of primary tumor

T1 Tumor 2 cm or smaller in greatest dimension, with or without

extraglandular extension into the orbital soft tissue

T2 Tumor larger than 2 cm but not larger than 4 cm in greatest dimension

T3 Tumor larger than 4 cm in greatest dimension

T4 Tumor invades periosteum or orbital bone or adjacent structures

T4a Tumor invades periosteum

T4b Tumor invades orbital bone

T4c Tumor invades adjacent structures (brain, sinus, pterygoid fossa,

temporal fossa)

Regional lymph nodes (N)

NX Regional lymph nodes cannot be assessed

N0 No regional lymph node metastasis

N1 Regional lymph node metastasis

Distant metastasis (M)

MX Distant metastasis cannot be assessed

M0 No distant metastasis

M1 Distant metastasis

Investigations

FNAC – Confirms possibility of lymphoma/inflammatory mass

CT scan – To see the deep lobe

Bone involvement

Extension into the base of the skull

Parapharyngeal space extension

Neck nodes assessment

MRI - Perineural spread

Bone marrrow involvement

Treatment

a) Surgery

- Total conservative parotidectomy

T1,T2,T3

- Radical Parotidectomy(T4)

- Both lobes

- Facial nerve

- Soft tissues with skin

- Mandibular ramus

- Masseter muscle

Facial N reconstruction – Greater auricular nerve/sural nerve

b) Radiotherapy

3-6 weeks after surgery

Delayed for 6 weeks if nerve grafting is done

Dose – 50-70 Gy (1.5 - 2Gy in 5-8 weeks.

c) Chemotherapy

5FU

Cisplatin

Doxurubicin

Epirubicin

Parotidectomy

Superficial parotidectomy:

Most common procedure of parotid pathology

With/without hypotensive anesthesia

Reduce blood loss

Improve visual surgical field

Steps

1) Incision and development of skin flap

Modified Bliar incision (Lazy ‘S’ preauricular-mastoid –

cervical inscision)

Skin flap is developed forward to the ant. border

2) Mobilization of gland

Aim to free the post. Margin to visualize the FN

Sharp disection along the ant. Border of

sternomastoid muscle to reach the

avascular plane

3) Location of the FN trunk

Landmark to identify FN

Colney’s pointer

Upper border of post. belly of digastric M

Retrograde tracing

4) Dissection of the gland

From superior to inferior direction

Upper div. is usually tortuous & can be damaged

easily

5) Closure – Trendelenburg position to identify any

residual bleeding.

Complications of parotidectomy

- Haematoma

- Infection

- Temporary facial weakness

- Permanent facial weakness

- Permanent numbness of ear lobe

- Frey’s syndrome

Frey’s syndrome

(gustatory sweating)

- Considered an inevitable consequence of parotidectomy,

unless preventative measures are taken

- Sweating, redness and warmth in the preauricular region

while eating

- Damage of autonomic innervation – inappropriate

regeneration of parasympathetic postganglionic fibers into

the skin overlying the parotd- sweating.

Diagnosis

Minor’s test (iodine test)

Iodine applied over affected area

Dry starch applied over it

Turns blue in the presence of sweat.

Prevention:

Barrier between skin and parotid bed

Sternomastoid muscle flap

Temporalis fascia flap

Artificial membrane

Management of established Frey’s syndrome

- Antiperspirants

- Anticholinergic lotion

- Denervation by tympanic neurectomy

- Injection of botulinum toxin into the affected

skin.

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