Contents of the Chapter

Tumours of the Temporal Bone

Introduction

Temporal bone tumours are rare benign or malignant neoplasms arising from the external auditory canal, middle ear, inner ear, petrous temporal bone, or adjacent skull base structures. Although uncommon, they are clinically important because they often mimic chronic ear infections, leading to delayed diagnosis. Squamous cell carcinoma is the most common malignant temporal bone tumour, whereas glomus tumours are the most common benign middle ear tumours. Early recognition, appropriate imaging, biopsy, and surgical management significantly improve outcomes.

This chapter provides MBBS, ENT PG, INI-CET, FMGE, and NEET PG students with complete notes, classification, diagnosis, staging, treatment, MCQs, viva questions, and revision points.

Definition

Temporal bone tumours are uncommon benign or malignant neoplasms arising from the external auditory canal, middle ear, inner ear, petrous temporal bone, or adjacent structures.

Epidemiology

Tumours of the middle ear & temporal bone are rare, with an estimated incidence of 1 in 5,000–20,000 otological patients or 6 cases per million in the general population. The disease is slightly more common in females and affects the age group of 40-60 years. Squamous cell carcinoma is the most common histologic type, accounting for over 80% of cases, followed by basal cell carcinoma. Despite advances in surgical techniques and radiotherapy, their prognosis remains poor, highlighting the importance of early detection.

Common Site of Origin

Most malignant temporal bone tumours arise from the external auditory canal, whereas tumours originating from the middle ear and other parts of the temporal bone are relatively uncommon.

Risk Factors for Temporal Bone Tumours

1. Genetic Factors:

Mutations in the NF2 gene (chromosome 22) are linked to certain temporal bone tumours.
Hereditary paragangliomas are associated with genes on chromosome 11q23.
Von Hippel-Lindau (VHL) disease (chromosome 3p25) is linked to endolymphatic sac tumours (ELSTs).

2. Radiation Exposure: A history of radiotherapy for head and neck conditions increases the risk of temporal bone malignancy, with a latency period of 5–30 years. The radiation-induced tumours, such as squamous cell carcinoma and osteosarcoma, are aggressive and metastasise early with poor survival rates.

3. Chronic Suppurative Otitis Media (CSOM) and Papillomatosis (Inverted papilloma):

CSOM is associated with squamous carcinoma of the temporal bone, though the exact mechanism is unclear.
Human papillomavirus (HPV) types 16/18 and 11 have also been reported to be additional risk factors.

Clinical features

Temporal bone tumours usually present with one or more of the following features:

Otalgia,
Chronic foul-smelling blood-stained discharge,
Hearing loss,
Vertigo
Presence of granulations or polyps on examination

All the above symptoms mimic benign conditions like otitis externa or chronic suppurative otitis media (CSOM) and therefore complicate its early detection. Given the rarity of malignancy, distinguishing between a CSOM and a malignant tumour, the diagnosis is often made in a late stage when the patient presents with facial palsy or bleeding from the ear. However, the pain associated with these tumours is typically more severe than that caused by non-neoplastic conditions.

Clinical Pearl: Persistent painful blood-stained ear discharge, granulation tissue, or an aural polyp that fails to respond to appropriate medical treatment should always raise suspicion of temporal bone malignancy and warrants a biopsy.

Spread of Tumour

The tumour of the external auditory canal spread anteriorly into the parotid gland and temporomandibular joint. The tumour of the middle ear destroys middle structures first and can spread anteriorly in the Eustachian tube & nasopharynx, superiorly in the middle cranial fossa, medially in the internal ear and inferiorly to involve the jugular foramen and lower cranial nerves. It may spread in a petrous pyramid towards its apex. Thus, the clinical features of temporal bone tumours may include:

Trismus
Hemifacial spasm or progressive facial weakness
Lower cranial nerve palsies (IX, X, XI and XII)
Headache and localised pain
Cervical metastases.

Diagnosis

Biopsy is essential for a definitive diagnosis.
CT scans reveal bone erosion, while MRI with gadolinium enhancement shows soft tissue infiltration. Both help assess the tumour stage, including dural involvement and infratemporal fossa spread.
PET-CT may be useful in advanced cases to detect regional lymph node involvement or distant metastasis.
Angiography is also useful in the assessment of disease.

Staging

No specific staging system exists for temporal bone tumours under the AJCC or UICC classification. The Modified Pittsburgh staging system is the most widely used staging system for squamous cell carcinoma of the external auditory canal and temporal bone and helps guide treatment planning and prognosis.

Treatment

Treatment depends on the tumour type, extent of disease, and patient factors. Complete surgical excision is the mainstay of treatment for most temporal bone tumours. Adjuvant radiotherapy is recommended for malignant tumours with advanced disease, positive surgical margins, perineural invasion, or other high-risk features. The treatment plan should be individualised according to the tumour type and stage.

Poor Prognostic Factors

Advanced tumour stage
Facial nerve palsy
Dural or brain invasion
Petrous apex involvement
Cervical lymph node metastasis
Positive surgical margins

Classification of Temporal Bone Tumours

Tumours of the temporal bone are classified based on their origin:

Cutaneous neoplasms: Squamous cell carcinoma, basal cell carcinoma, malignant melanoma.
Glandular neoplasms: Ceruminous adenoma, pleomorphic adenoma, adenoid cystic carcinoma, middle ear adenoma, endolymphatic sac tumours.
Vascular/haematological: Haemangioma, haemangiopericytoma, lymphoma, Langerhans cell histiocytosis
Paraganglioma: Glomus tympanicum, glomus jugulare, glomus vagale. (Detailed Glomus Tumour link: https://www.entlecture.com/glomus-tumour/ )
Bone tumours: Osteoma, rhabdomyosarcoma, chondrosarcoma, Ewing sarcoma, chordoma.
Neural tumours: Schwannomas, meningiomas.
Developmental and congenital tumours: Chordoma, dermoid, teratoma.

Cutaneous Neoplasms

Squamous cell carcinoma: Squamous cell carcinoma (SCC) is the most common malignant tumour of the temporal bone, with an incidence of fewer than 6 cases per million annually, primarily affecting males in their seventh decade. Early-stage tumours have favourable outcomes (80–100% survival), while advanced disease (T4) has a poorer prognosis (~40% survival).

Treatment involves surgical management: lateral temporal bone resection for tumours lateral to the tympanic membrane, extended temporal bone resection for advanced disease, and neck dissection for node-positive disease. The facial nerve is preserved whenever oncologically safe; however, nerve sacrifice with resection of involved dura or brain may be necessary in advanced tumours with direct tumour invasion. Reconstruction is performed using free tissue transfer (e.g., anterolateral thigh flap), and adjuvant radiotherapy (60 Gy) improves local control and survival, particularly in advanced disease.

Glandular Neoplasms

Glandular tumours of the external auditory canal:

Ceruminous adenoma: A benign tumour of ceruminous glands, treated with wide excision as local recurrence is common; radiotherapy is ineffective.
Pleomorphic adenoma: A benign tumour that requires careful wide excision to avoid local seeding of the local tissues by spillage of the tumour during excision.
Adenoid cystic carcinoma: It is an aggressive malignant tumour, with major local tissue destruction, & perineural and vascular invasion. Managed with aggressive surgical resection and radiotherapy, though prognosis remains poor.
Ceruminous adenocarcinoma: It is a rare malignant tumour, treated with surgery with post-operative radiotherapy.

Middle ear adenoma: A benign tumour of middle ear mucosa, confined to the middle ear cleft with no bony erosion or metastasis, treated with local excision (tympanotomy or mastoid approach); no role of radiotherapy; excellent prognosis.

Endolymphatic sac tumours (ELSTs): Endolymphatic sac tumours (ELSTs) are rare, slow-growing but locally aggressive neoplasms often associated with Von Hippel-Lindau (VHL) disease. The most prominent clinical feature is progressive unilateral sensorineural hearing loss, accompanied by tinnitus and vertigo. ELSTs are highly vascular and exhibit aggressive bone invasion without metastatic spread; treated with surgical resection; excellent prognosis for both survival and hearing preservation; radiotherapy is reserved only for palliative cases. The tumour may spread into the cerebellopontine angle and posterior fossa.

Other Temporal Bone Tumours

1. Inverted papilloma: Rare, with potential for malignant transformation. Treated with surgery and radiotherapy if carcinoma is present.

2. Haemangioma: Benign, often regresses spontaneously; surgery is reserved for symptomatic cases.

3. Haemangiopericytoma: Rare and unpredictable; treated with wide excision and pre-operative embolisation.

4. Osteoma: Benign, often asymptomatic; surgery is considered if hearing loss occurs.

5. Chordoma and chondrosarcoma: Aggressive tumours requiring multidisciplinary management, including surgery and proton beam radiotherapy. Prognosis is better for chondrosarcoma than chordoma.

6. Secondary Tumours of the Temporal Bone: Secondary tumours may result from local spread (e.g., from the parotid or pharynx), distant metastases (e.g., breast, lung, kidney), or haematological malignancies. Symptoms include hearing loss, vertigo, and facial paralysis. Prognosis is poor, and management is individualized based on the primary tumour.

Temporal Bone Tumours in Childhood

1. Rhabdomyosarcoma (RMS): Rhabdomyosarcoma (RMS) is a highly aggressive tumour originating from striated muscle tissue or pluripotential mesenchyme, with the potential for local spread and metastasis. Although rare, it is the most common soft tissue tumour in children under 12 years of age. The embryonal subtype is the most common histological variant. In the head and neck region, RMS of the ear is the third most common site, following the nasopharynx and orbit. Common presentations include a mass, aural polyp, or ear discharge, with facial palsy often occurring early in the disease course.

Diagnosis is confirmed through biopsy, as clinical and imaging findings alone are insufficient. Management primarily involves chemotherapy and radiotherapy, with surgery playing a limited role. RMS has a poor prognosis, but treatment advancements have improved outcomes. Over time, survival rates have increased, with the 5-year survival rate now reaching 73%.

2. Langerhans Cell Histiocytosis (LCH): It is characterized by the proliferation of histiocytes and can involve the temporal bone, often mimicking CSOM. CT typically demonstrates characteristic punched-out osteolytic lesions of the temporal bone. Treatment depends on disease extent: unifocal disease has an excellent prognosis with local treatment, while disseminated disease is often fatal.

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High-Yield Points for NEET PG & University Exams

Squamous cell carcinoma (SCC) is the most common malignant tumour of the temporal bone, accounting for over 80% of cases.
Glomus tympanicum is the most common benign tumour of the middle ear.
The most common site of origin for malignant temporal bone tumours is the external auditory canal.
The most common symptom of temporal bone malignancy is chronic painful blood-stained ear discharge.
Facial nerve palsy in a patient with chronic ear disease is a red flag for malignancy until proven otherwise.
Biopsy is essential for definitive diagnosis, but contraindicated in suspected glomus tumours due to bleeding risk.
Modified Pittsburgh staging system is the most widely used staging system for temporal bone SCC.
Poor prognostic factors include: advanced stage, facial palsy, dural/brain invasion, petrous apex involvement, cervical metastasis, and positive margins.
Lateral temporal bone resection is the surgical procedure for tumours lateral to the tympanic membrane.
Extended temporal bone resection is required for advanced disease involving the middle ear or petrous apex.
Adjuvant radiotherapy (60 Gy) improves local control and survival in advanced temporal bone SCC.
Rhabdomyosarcoma is the most common soft tissue tumour in children under 12 years and the third most common head and neck RMS site is the ear.
Langerhans Cell Histiocytosis shows punched-out osteolytic lesions on CT and can mimic CSOM.
Endolymphatic sac tumours (ELSTs) are associated with Von Hippel-Lindau (VHL) disease (chromosome 3p25).
Adenoid cystic carcinoma is aggressive with perineural invasion and requires aggressive surgical resection with radiotherapy.
Middle ear adenoma is benign, confined to the middle ear, and has an excellent prognosis with local excision.
Chordoma has a poorer prognosis than chondrosarcoma; both require proton beam radiotherapy.
Radiation-induced temporal bone tumours have a latency period of 5-30 years and are aggressive with poor survival.
HPV types 16/18 and 11 are additional risk factors for temporal bone SCC.
Secondary tumours of the temporal bone most commonly arise from breast, lung, and kidney primaries.

Frequently Asked Questions

What is the most common malignant tumour of the temporal bone?
The most common malignant tumour of the temporal bone is squamous cell carcinoma (SCC), accounting for over 80% of all temporal bone malignancies. It typically arises from the external auditory canal and presents with persistent painful blood-stained ear discharge.
What are the red flag signs of temporal bone malignancy?
The red flag signs of temporal bone malignancy include persistent painful blood-stained ear discharge, granulation tissue or an aural polyp that fails to respond to medical treatment, and facial nerve palsy in a patient with chronic ear disease. Any of these findings warrants an urgent biopsy.
What is the Modified Pittsburgh staging system for temporal bone tumours?
The Modified Pittsburgh staging system classifies temporal bone squamous cell carcinoma as: T1 (limited to EAC without bone erosion), T2 (limited bone erosion), T3 (eroding otic capsule or involving middle ear/mastoid), and T4 (involving dura, brain, or lower cranial nerves). This system guides treatment planning and prognosis.
How is squamous cell carcinoma of the temporal bone treated?
Treatment involves complete surgical excision with lateral temporal bone resection for early tumours or extended temporal bone resection for advanced disease, followed by adjuvant radiotherapy (60 Gy) for high-risk features. Neck dissection is performed for node-positive disease. Reconstruction uses free tissue transfer techniques.
What is the most common childhood temporal bone tumour?
Rhabdomyosarcoma (RMS) is the most common childhood temporal bone tumour, presenting as an aural polyp or mass with early facial nerve palsy. The embryonal subtype is most common, and management primarily involves chemotherapy and radiotherapy, with limited surgical role. The 5-year survival rate is approximately 73%.

NEET PG-Style MCQs

The most common malignant tumour of the temporal bone is: A. Basal cell carcinoma B. Squamous cell carcinoma C. Adenoid cystic carcinoma D. Rhabdomyosarcoma.
The most common benign tumour of the middle ear is: A. Osteoma B. Haemangioma C. Glomus tympanicum D. Middle ear adenoma.
The most common site of origin for malignant temporal bone tumours is: A. Middle ear B. Inner ear C. External auditory canal D. Petrous apex.
The red flag sign that should raise suspicion of temporal bone malignancy is: A. Conductive hearing loss B. Persistent painful blood-stained ear discharge C. Tinnitus D. Vertigo.
Biopsy of a suspected temporal bone tumour is contraindicated in: A. Squamous cell carcinoma B. Glomus tumour C. Adenoid cystic carcinoma D. Rhabdomyosarcoma.
The Modified Pittsburgh staging system is used for: A. Glomus tumours B. Vestibular schwannoma C. Squamous cell carcinoma of temporal bone D. Rhabdomyosarcoma.
The most common soft tissue tumour in children under 12 years is: A. Osteoma B. Rhabdomyosarcoma C. Langerhans Cell Histiocytosis D. Haemangioma.
Endolymphatic sac tumours are associated with: A. Neurofibromatosis Type 2 B. Von Hippel-Lindau disease C. Tuberous sclerosis D. Sturge-Weber syndrome.
Adenoid cystic carcinoma of the temporal bone is characterised by: A. Excellent prognosis B. Perineural invasion C. No bony erosion D. Responsive to chemotherapy alone.
The surgical procedure for squamous cell carcinoma limited to the external auditory canal is: A. Modified radical mastoidectomy B. Lateral temporal bone resection C. Extended temporal bone resection D. Radical mastoidectomy.

MCQs Answers: 1: B. 2: C. 3: C. 4: B. 5: B. 6: C. 7: B. 8: B. 9: B. 10: B.

Clinical Case Scenarios for Practical Exams & Viva

Case 1.A 65-year-old male smoker presents with right-sided ear pain, blood-stained discharge, and progressive hearing loss for 4 months. He was treated for CSOM with antibiotics but shows no improvement. On examination, there is a friable, bleeding polyp in the external auditory canal. Most likely diagnosis: Squamous cell carcinoma of the temporal bone. Best next step: Biopsy under anaesthesia. Best management: Lateral temporal bone resection + adjuvant radiotherapy.
Case 2.A 55-year-old female presents with pulsatile tinnitus and progressive hearing loss. Otoscopy reveals a reddish-blue reflex through an intact tympanic membrane. On applying pressure with a Siegel’s speculum, the mass blanches and then pulsates vigorously. Most likely diagnosis: Glomus tympanicum. Best investigation: CT temporal bone and MRI with gadolinium. Best management: Surgical resection; biopsy is contraindicated.
Case 3.A 10-year-old child presents with right ear discharge, a fleshy aural polyp, and right facial nerve palsy. The child has no history of CSOM. Most likely diagnosis: Rhabdomyosarcoma of the temporal bone. Best investigation: Biopsy and MRI. Best management: Chemotherapy + radiotherapy; surgery has a limited role.
Case 4.A 50-year-old patient with known Von Hippel-Lindau disease presents with progressive right-sided hearing loss, tinnitus, and vertigo. MRI shows a vascular mass involving the endolymphatic sac. Most likely diagnosis: Endolymphatic sac tumour (ELST). Best management: Surgical resection; excellent prognosis for survival and hearing preservation.

Frequently Asked Questions in Viva

Q: What is the most common malignant tumour of the temporal bone?
A: Squamous cell carcinoma (SCC) is the most common malignant tumour, accounting for over 80% of temporal bone malignancies.
Q: What are the red flag signs of temporal bone malignancy?
A: Persistent painful blood-stained ear discharge, granulation tissue or polyp that fails to respond to medical treatment, and facial nerve palsy in a patient with chronic ear disease.
Q: Why is biopsy contraindicated in glomus tumours?
A: Biopsy is contraindicated because glomus tumours are highly vascular, and biopsy carries a risk of catastrophic haemorrhage.
Q: What is the Modified Pittsburgh staging system?
A: T1 (limited to EAC without bone erosion), T2 (limited bone erosion), T3 (eroding otic capsule or involving middle ear/mastoid), T4 (involving dura, brain, or lower cranial nerves).
Q: What is the most common childhood temporal bone tumour?
A: Rhabdomyosarcoma is the most common childhood temporal bone tumour, presenting with aural polyp and early facial nerve palsy.
Q: What is the surgical treatment for SCC of the temporal bone?
A: Lateral temporal bone resection for tumours lateral to the tympanic membrane; extended temporal bone resection for advanced disease; neck dissection for node-positive disease.
Q: What is the prognosis of endolymphatic sac tumours?
A: Excellent prognosis for both survival and hearing preservation with surgical resection. Radiotherapy is reserved for palliative cases.

Summary: Key Takeaways

Squamous cell carcinoma is the most common malignant temporal bone tumour (over 80% of cases).
Glomus tympanicum is the most common benign middle ear tumour.
External auditory canal is the most common site of origin for malignant temporal bone tumours.
Red flag signs: Persistent painful blood-stained discharge, non-healing granulations/polyp, facial nerve palsy.
Biopsy is essential for diagnosis but contraindicated in glomus tumours.
Modified Pittsburgh staging guides treatment and prognosis for SCC.
Treatment: Surgery is mainstay; adjuvant radiotherapy (60 Gy) improves outcomes.
Poor prognostic factors: Advanced stage, facial palsy, dural/brain invasion, petrous apex involvement, cervical metastasis.
Rhabdomyosarcoma is the most common childhood temporal bone tumour.
ELSTs are associated with VHL disease and have excellent prognosis with surgery.

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Download full PDF Link: Tumours of Temporal Bone Best Lecture Notes Dr Rahul Bagla ENT Textbook

Reference Textbooks.

Scott-Brown, Textbook of Otorhinolaryngology-Head and Neck Surgery.
Glasscock-Shambaugh, Textbook of Surgery of the Ear.
P L Dhingra, Textbook of Diseases of Ear, Nose and Throat.
Hazarika P, Textbook of Ear Nose Throat And Head Neck Surgery Clinical Practical.
Mohan Bansal, Textbook of Diseases of Ear, Nose and Throat Head and Neck Surgery
Hans Behrbohm, Textbook of Ear, Nose, and Throat Diseases With Head and Neck Surgery.
Salah Mansour, Middle Ear Diseases – Advances in Diagnosis and Management.
Logan Turner, Textbook of Diseases of The Nose, Throat and Ear Head And Neck Surgery.
Rob and smith, Textbook of Operative surgery.
Anirban Biswas, Textbook of Clinical Audio-vestibulometry.
Arnold, U. Ganzer, Textbook of Otorhinolaryngology, Head and Neck Surgery.

Author:

Dr. Rahul Bagla
MBBS (MAMC, Delhi) MS ENT (UCMS, Delhi)
Fellow Rhinoplasty & Facial Plastic Surgery.
Renowned Teaching Faculty
Mail: msrahulbagla@gmail.com
India

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Please read. Anatomy of External Ear. https://www.entlecture.com/anatomy-of-ear/
Please read. Anatomy of Temporal Bone. https://www.entlecture.com/anatomy-of-temporal-bone/
Please read. Stenger’s, Chimani Moos, Teal test. https://www.entlecture.com/special-tuning-fork-tests/

Keywords: Rare temporal bone tumours, Squamous cell Carcinoma Temporal Bone, Endolymphatic sac tumour treatment, Glomus tympanicum surgery, Adenoid cystic carcinoma temporal bone, Ceruminous adenoma external ear, Middle ear adenoma symptoms, Radiation-induced temporal bone tumours, Von Hippel-Lindau disease and ELST, Temporal bone tumour diagnosis, Chondrosarcoma of the skull base, Chordoma temporal bone treatment, Haemangioma middle ear management, Inverted papilloma temporal bone, Rhabdomyosarcoma in children ear, Langerhans cell histiocytosis temporal bone, Chronic otitis media and temporal bone cancer, Temporal bone tumour staging systems, Skull base tumours and hearing loss, Rare ear tumours and facial palsy, Molecular genetics of temporal bone tumours

Tumours of Temporal Bone