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• The external, middle, and inner components of the ear develop from
the three embryonic layers: ectoderm, mesoderm, and endoderm
• The external ear consists of :
auricle or pinna,
external auditory meatus (canal),
• Auricle: composed of elastic cartilage covered with skin.
• External auditory meatus :
connects the tympanic membrane to the exterior
2.4 cm long.
outer 1/3rd - cartilaginous, inner 2/3rd is bony and slightly narrower.
related anteriorly to parotid gland at the TM joint; Inferiorly, jugular bulb
and facial nerve.
Skin lining is continuous with auricle, outer 1/3rd contains hair follicles,
sebaceous and ceruminous glands.
• Tympanic membrane: made of multiple layers of squamous epithelium;
separates auditory canal from middle ear.
• Middle ear contains:
• Opens into the eustachian tube to communicate with the pharynx.
• Cavity is lined with mucoperiosteal membrane and eustachian tube is lined
with stratified columnar epithelium, has mucous glands in 2/3 rd of the
tube closer to the pharynx.
• Overall length of eustachian tube is 3.5 cm.
• Lies in petrous portion of temporal bone and consists of :
• The membranous labyrinth: holds the organ of hearing, is housed
within the bony labyrinth.
• Cochlea: responsible for hearing
• Vestiblule: responsible for balance
Parts of inner ear
• Auricle & external auditory canal:
branches of the posterior auricular artery
superficial temporal artery, which arise from the external carotid artery.
• Middle ear:
branches of ascending pharyngeal Artery
middle meningeal arteries
artery of the pterygoid canal.
• Inner ear :
internal auditory artery - branch of the basilar artery
anterior inferior cerebellar artery.
• The nerves innervating the ear:
cranial nerves V, VIII, IX, and X.
The VIII or vestibulocochlear nerve:
arises at the lateral termination of the internal acoustic meatus and
ends in the brainstem between pons and medulla.
responsible for auditory and vestibular function.
• External ear:
Lymphatic vessels of the tragus and anterior external portion of the
auricle: superficial parotid lymph nodes.
posterior and superior aspects of auricle: retroauricular lymph nodes
Lobule: superficial cervical group of lymph nodes.
• Middle ear and mastoid antrum:
sparse lymphatic drainage
parotid nodes and upper deep cervical lymph nodes.
• Inner ear: no lymphatics.
through the concha into the postauricular sulcus
posteriorly into the mastoid
4 through the tympanic membrane into the middle ear
Into the inner ear through
the round window or otic
Into the anterior
mesotympanum to the
carotid artery and
Inferomedially into the jugular fossa,
carotid artery, and lower cranial
Along the extratemporal facial nerve into the infratemporal fossa7
• Malignant disease of the auricle is common but cancers of middle ear and
external auditory canal are rare.
• Incidence: 1 per million.
• External ear:
most common are cutaneous malignancies, related to sun exposure.
Other predisposing factors: otorrhea, chronic eczema, chronic dermatologic
conditions, and chronic ulcerations from trauma.
most common in 60 to 70 years of age.
More common in males.
• Middle ear and the mastoid:
more common in 40 to 60 years of age.
More common in females.
• External Ear:
• Basal cell carcinomas are more common than squamous cell
carcinomas (1.3 :1)
• Present as small ulcerations, mostly on helix.
• SCC: lymph nodes metastasis in 10-15%.
• Common LN metastasis sites: parotid glands, upper deep cervical
nodes and postauricular nodes.
• Regional metastasis is higher in advanced disease and may involve
level V LNs.
External Auditory Canal
• Mostly symptomatic
• Pruritus and pain – common
• Advanced cases : Swelling behind the ear, decreased hearing and
• Spread of the tumor into lymphatic areas: common
• Distant metastases rare
Tumors in cartilaginous portion of canal:
invade cartilaginous walls and spread to bony canal.
Tumors in bony canal :
more effective barrier preventing spread;
Progress along main axis of canal, eventually invading middle ear or
• A baseline audiology testing should be performed before any
• Both CT and MRI play an important role in vizualizing tumors of ear.
• CT scan:
• CT can show abnormal soft tissue, soft tissue enhancement, and
distortion of the normal tissue planes.
• Most importantly, when evaluating EAC tumor, CT can provide
accurate prediction of bone erosion, such as wall of the EAC, middle
ear, TMJ, carotid artery canal, and jugular fossa and thus can help to
determine the extension and the operability of tumors
• MRI can differentiate the tumor from mastoiditis and cholesteatomas
and provide excellent delineation of soft tissue tumor margins,
muscle infiltration, intracranial extension, dural or cerebral
involvement, and vessel encasement.
• Diagnosis is always established by biopsy and occasionally by
aspiration of the exudative material or by surgical exploration.
• A bone scan may be done to determine the changes in temporal bone
around the tumor, but it provides very nonspecific information and is
not a recommended method of evaluation.
• Approx. 85% of the tumors involving auditory canal, middle ear, and mastoid
area are squamous cell carcinomas.
Basal cell carcinomas,
Adenoid cystic carcinomas,
Sarcomas, specifically embryonic rhabdomyosarcomas.
Ceruminous gland tumors and papillomas (rarely arise in the auditory canal)
Carcinoid tumor of the middle ear (50 case reports)
Endolymphatic sac tumor or aggressive papillary middle ear tumors:
(characterized by slow growth but extensive local invasion and bone destruction)
• Lesions of the external ear are more easily controlled than middle ear
• Presence of large lesions involving the middle ear and those with
extension into the temporal bone or soft tissue is a poor prognostic
sign and more difficult to treat.
• No correlation between tumor differentiation, positive margins, or
perineural disease and survival, they are predictor for local control in
tumors involving the temporal bone.
• Seventh cranial nerve palsy associated with middle ear tumors
indicates poor survival
• Spread of tumors to the lymph nodes usually indicates a poor
• The seventh edition of the American Joint Committee on Cancer
(AJCC) staging manual includes the external ear in its staging system
under Cutaneous Squamous Cell Carcinoma and Other Cutaneous
• A group from the University of Pittsburgh proposed a staging system
for squamous cell carcinoma of the external auditory canal and
temporal bone, which was updated in 2002.
• The primary tumor stage is determined by the level of bony erosion,
size, and involvement of the middle ear.
• Lymph node disease is considered advanced stage with poor
prognosis. This staging system has often been cited in the literature
• Most often treated with limited surgery or external radiation therapy.
• Treatment in early stages: irradiation in form of megavolatage
electron beam therapy.
• Dose: 66 – 70 Gy in 1.8 to 2 Gy per fraction for 6.5 – 7 weeks
• Local control rates: 80 -97%
• Surgery : beneficial if lesion has invaded cartilage of ear or extends
medially into auditory canal.
• If squamous cell carcinoma of external ear is treated with surgery
alone: recurrence rate 14- 19%
• Advanced lesions involving ear canal- managed with combination of
irradiation and surgery.
• Treatment of draining lymphatics : not required for early stages of
external ear tumors.
• Prophylactic neck dissection indicated in :
lesions over 4 cm
Lesions with cartilage invasion due to increased risk of nodal spread.
Overall chance of lymph node involvement in tumors of external ear:
• Interstitial irradiation using afterloading 192Ir, particularly for tumors
<4 cm: effective method of treatment, affording excellent local
control with good cosmesis.
• Radical surgery and postoperative radiation therapy are the accepted
methods of treatment for more advanced lesions of external
auditory canal, middle ear and mastoid.
• Post op radiotherapy dose:
For negative margins: 54 -60 Gy.
For positive margins: upto 66 Gy.
• Lesions of the outer part of the auditory canal require local excision with at
least a 1-cm margin between the lesion and the tympanic membrane
• Surgery for tumors of the auditory canal is performed through a U-shaped
incision with elevation of the flap from below.
• A split-thickness skin graft is usually required to cover the deficit along the
• When the tumor involves the bony auditory canal and impinges on the
tympanic membrane but does not involve the middle ear or the mastoid, a
partial temporal bone resection may be necessary; in this procedure, the
auditory canal, tympanic membrane, malleus, and incus are removed along
with the TMJ, and the defect is grafted with a split-thickness skin graft
Middle Ear and Temporal Bone
• In management of temporal bone tumors originating from middle ear and
mastoid area, the surgical options are :
lateral temporal bone resection,
subtotal temporal bone resection,
total temporal bone resection.
• Postoperative radiation therapy is essential to increase chance of local
tumor control as complete resections with clear margins is difficult to
• Chemotherapy has not been beneficial in tumors of ear.
New RT Technique
• Stereotactic ablative radiotherapy (SABR) may represent a new
treatment option for organ preservation.
• A study used 37.5 Gy/3 fractions or 40 Gy/5 fractions radiotherapy as
a first-line treatment, resulting in 3-year OS rates: 69% for T1/2, 79%
for T3 (95% CI, 47–93), and 0% for T4 disease with limited toxicities.
• Chemotherapy has been used in tumors of the ear.
• The common regimen includes cisplatin, docetaxel, and mitomycin via
intravenous or intra-arterial.
• A meta-analysis suggested that preoperative CRT followed by surgery
may improve the survival of patients with external auditory canal SCC
and that definitive CRT may be equivalent to surgical resection.
• However, additional trials are necessary to determine efficacy
because there was no control trial in this meta-analysis.
Radiation Therapy Techniques
• Tumors involving the pinna can be treated with electron or
• Fields : round or polygonal, drawn around the tumor to spare
surrounding normal tissues.
• For small superficial tumors: margins of 1 cm are adequate.
• For extensive lesions: large portal including entire pinna or external
canal with 2- to 3-cm margins around clinically apparent tumor.
• Lesions involving pinna: treated with low dose per fraction(1.8 to 2
Gy daily) to prevent cartilage necrosis.
• Doses of 65 Gy over a period of 6.5 weeks are required to achieve
adequate tumor control.
Lesions of external auditory canal:
treated with irradiation alone or combined with surgery.
Portals: include entire ear and temporal bone with adequate margin
includes ipsilateral preauricular, postauricular, and subdigastric
Treating lymphatics beyond jugulodigastric area is usually not
Improves target coverage and spares normal critical structures.
advanced external auditory canal and middle ear tumors:
GTV: clinical and radiographic gross disease.
CTV1: GTV with 0.3 -0.5 cms margin to a dose of 66-70 Gy at 2 Gy
CTV2: CTV1 with 0.5 -0.7 cms margin + preauricular and post
auricular LNs with ipsilateral level II LN and parotid gland to a dose
of 63 Gy at 1.8 Gy per fraction.
CTV3: for ipsilateral level III and IV LNs and contralateral level II to a
dose of 56 Gy at 1.6 Gy per fraction.
PTV: 3-5 mm margin around CTVs.
• Treated with:
High-energy ipsilateral electron beam therapy (16 to 20 Mev) alone
Mixed with photons (4 to 6 MV) or
With wedge pair (superior inferiorly angled beams) techniques using
low-energy photons or
• Dose: 60 to 70 Gy over 6 to 7 weeks.
• Doses higher than this produces osteoradionecrosis of temporal
• When electron beam radiation therapy is used, use of water bolus in
external auditory canal and concha reduce auricular complications.
Palliative Radiation Therapy
In recurrent or advanced disease.
Pain relief is reported in 61% patients with tumors of auditory canal
and middle ear.
Recurrences developing after previous irradiation may be retreated
with low-dose radiation therapy: tumor control in 20% patients.
When small-volume local recurrence occurs after previous radiation
therapy, fractionated high-dose-rate treatment may be considered.
Results of Therapy
Overall 5-year survival rates with combination therapy for :
Patients with earlier-stage tumors achieve 70% survival rate at 5
years with no evidence of disease
Tumors involving the middle ear and external auditory canal -40% to
Negative effect of extent of disease on survival without evidence of
Sequelae of Treatment
• Possible sequelae with surgery:
Loss of facial nerve function,
Rarely, Carotid artery thrombosis.
Occasionally, vertigo is reported after temporal bone resection.
Permanent deafness on operated side.
Radiation therapy sequelae:
Xerostomia (30% incidence)
Osteoradionecrosis of temporal bone. (10% incidence after 60 to 65
Cutaneous and Cartilage necrosis of external auditory canal. ( 4%
Rarely, secondary infection and meningitis.