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Tumours of Maxillary, Ethmoid, Frontal & Sphenoid Sinuses
MedMentor EDU | ENT Study Notes for MBBS, NEET-PG, INI-CET & MS ENT
Introduction & Epidemiology
Applied Anatomy Relevant to Sinonasal Tumours
Etiology & Risk Factors
Premalignant Lesions
Classification of Paranasal Sinus Tumours
Pathways of Tumour Spread
Maxillary Sinus Carcinoma
Ohngren's & Lederman Classification
Ethmoid, Frontal & Sphenoid Sinus Tumours
Inverted Papilloma
Olfactory Neuroblastoma
Fibrous Dysplasia & Juvenile Ossifying Fibroma
Clinical Evaluation
Investigations
Staging
Management
Reconstruction After Maxillectomy
Follow-Up
Complications
Prognosis
Master Comparison Tables
High-Yield Exam Pearls
Paranasal sinus neoplasms are benign or malignant tumours arising from:
Maxillary sinus
Ethmoid sinus
Frontal sinus
Sphenoid sinus
They may arise from:
Mucosal epithelium
Minor salivary glands
Bone
Cartilage
Neuroectodermal tissue
Lymphoid tissue
Sinonasal malignancies constitute:
<1% of all human malignancies
3% of head and neck cancers
| Site | Frequency |
|---|---|
| Maxillary sinus | 70–80% |
| Ethmoid sinus | 10–15% |
| Nasal cavity | 10–15% |
| Sphenoid sinus | Rare |
| Frontal sinus | Very rare |
Peak incidence: 50–70 years
Rare in children
Male : Female ≈ 2:1
Most common malignant tumour of paranasal sinuses = Squamous cell carcinoma
Most common site of paranasal sinus malignancy = Maxillary sinus
Largest paranasal sinus.
Roof
Orbit
Floor
Alveolar process
Upper molar teeth
Medial Wall
Nasal cavity
Anterior Wall
Cheek
Posterior Wall
Pterygopalatine fossa
Infratemporal fossa
Important relations:
Orbit (lamina papyracea)
Anterior cranial fossa
Optic nerve
Therefore early:
Proptosis
Diplopia
Intracranial extension
Relations:
Anterior cranial fossa
Orbit
Important relations:
Optic nerve
Cavernous sinus
Internal carotid artery
Pituitary gland
Cranial nerves III, IV, V1, V2, VI
→ Submandibular nodes
→ Upper deep cervical nodes
→ Retropharyngeal nodes
→ Upper deep cervical nodes
Very High Yield
| Occupation | Tumour |
|---|---|
| Wood workers | Adenocarcinoma |
| Furniture industry | Adenocarcinoma |
| Leather workers | Adenocarcinoma |
| Nickel industry | SCC |
| Chromium exposure | SCC |
| Textile workers | Sinonasal carcinoma |
Smoking
Air pollution
Radiation exposure
Associated with:
SCC
Sinonasal papilloma
Associated with:
Nasopharyngeal carcinoma
Some sinonasal malignancies
Chronic sinusitis
Chronic inflammation
Nasal polyposis
Inverted papilloma
Most important premalignant lesion.
Leukoplakia
Epithelial dysplasia
Risk highest in:
Malignant transformation:
5–15%
Usually transforms into:
Squamous Cell Carcinoma
Inverted papilloma
Fungiform papilloma
Oncocytic papilloma
Osteoma
Osteoblastoma
Fibrous dysplasia
Juvenile ossifying fibroma
Fibroma
Hemangioma
Neurofibroma
Schwannoma
Chondroma
Squamous cell carcinoma (most common)
Verrucous carcinoma
Adenocarcinoma
Adenoid cystic carcinoma
Mucoepidermoid carcinoma
Neuroendocrine carcinoma
Sinonasal undifferentiated carcinoma (SNUC)
Osteosarcoma
Chondrosarcoma
Fibrosarcoma
Rhabdomyosarcoma
Olfactory neuroblastoma
Mucosal melanoma
Lymphoma
Plasmacytoma
Direct extension into:
Orbit
Nasal cavity
Oral cavity
Pterygopalatine fossa
Causes:
Proptosis
Diplopia
Visual loss
Through:
Cribriform plate
Ethmoid roof
Frontal sinus posterior wall
Classically seen in:
Common nerves:
Infraorbital nerve
Trigeminal branches
To:
Submandibular nodes
Retropharyngeal nodes
Upper deep cervical nodes
Common sites:
Lung
Liver
Bone
Most common malignant tumour of paranasal sinuses.
Most are:
SCC
Adenocarcinoma
Adenoid cystic carcinoma
Mucoepidermoid carcinoma
Unilateral nasal obstruction
Blood-stained discharge
Recurrent epistaxis
Facial discomfort
Facial swelling
Facial pain
Trismus
Proptosis
Diplopia
Palatal swelling
Loose teeth
Nasal obstruction
Epistaxis
Cheek swelling
Loose teeth
Palatal bulge
Proptosis
Diplopia
Trismus
Pterygopalatine fossa involvement
Imaginary line:
Medial canthus → angle of mandible
Divides maxillary sinus into:
Above line
Poor prognosis
Below line
Better prognosis
Suprastructure tumours have poorer prognosis because of early orbital and skull base invasion.
Better prognosis
Poor prognosis
Due to:
Skull base involvement
Orbital invasion
Benign epithelial tumour characterized by:
Unilateral nasal obstruction
Unilateral discharge
Epistaxis
Nasal mass
Unilateral soft tissue mass
Bone remodeling
Characteristic:
High-yield sign.
Endophytic epithelial growth
Intact basement membrane
Treatment of choice.
Rare malignant neuroectodermal tumour arising from:
Located in:
Roof of nasal cavity
Cribriform plate region
Superior turbinate region
Rare tumour
Bimodal age distribution
2nd decade
5th–6th decade
Unilateral nasal obstruction
Epistaxis
Nasal mass
Proptosis
Diplopia
Headache
Seizures
Personality changes
Confined to nasal cavity
Involves paranasal sinuses
Extension beyond sinonasal region
Nodal or distant metastasis
Soft tissue mass
Bone destruction
Cribriform plate erosion
Better for:
Intracranial extension
Orbital involvement
Characteristic findings:
Small round blue cells
Neurofibrillary background
Homer-Wright rosettes
Current trend:
5-year survival:
Approximately 60–80%
Depends upon:
Kadish stage
Intracranial extension
Nodal metastasis
Benign fibro-osseous disorder in which:
Normal bone
↓
Replaced by fibrous tissue and immature bone
Single bone involved
Most common
Multiple bones involved
May be associated with:
Facial asymmetry
Facial swelling
Nasal obstruction
Proptosis
Cosmetic deformity
Characteristic:
Very High Yield
Irregular woven bone
Chinese letter pattern
Fibrous stroma
For stable lesions
For cosmetic deformity
Rarely required
Aggressive fibro-osseous tumour occurring in children and adolescents.
Facial swelling
Nasal obstruction
Proptosis
Orbital displacement
Well-defined expansile lesion
Mixed radiolucent-radiopaque appearance
High recurrence if incompletely removed.
Nasal obstruction
Epistaxis
Very common
Proptosis
Diplopia
Epiphora
Late feature
DNE
CT
MRI
Endoscopic resection
Craniofacial resection
Radiotherapy
Rare
Forehead swelling
Headache
Frontal deformity
Orbital displacement
Surgical excision
Craniofacial surgery
Very rare
May involve:
II
III
IV
V
VI
Produces:
Diplopia
Visual loss
Retro-orbital pain
Investigation of choice
Allows:
Direct visualization
Site identification
Biopsy
Gold standard for diagnosis.
Historical importance only.
May show:
Opacification
Bone destruction
Investigation of Choice for Bony Anatomy
Shows:
Bone erosion
Tumour extent
Orbital invasion
Skull base destruction
Investigation of Choice for Soft Tissue Spread
Shows:
Perineural spread
Intracranial extension
Orbital involvement
Used for:
Metastasis detection
Recurrence
Follow-up
Definitive diagnosis.
Useful in:
Olfactory neuroblastoma
Lymphoma
SNUC
Melanoma
| Feature | CT | MRI |
|---|---|---|
| Bone erosion | Excellent | Poor |
| Soft tissue | Moderate | Excellent |
| Orbit | Good | Excellent |
| Intracranial spread | Moderate | Excellent |
| Perineural spread | Poor | Excellent |
T1
Limited to mucosa
T2
Bone erosion
T3
Invades posterior wall/floor/orbit
T4
Skull base/intracranial extension
Based on:
Orbital invasion
Skull base invasion
Intracranial extension
Stage I → IV
Used for treatment planning and prognosis.
Treatment depends upon:
Histology
Stage
Site
Operability
Suitable for:
Early tumours
Selected sinonasal malignancies
Removal of:
Medial wall of maxillary sinus
Used in:
Inverted papilloma
Selected malignancies
Limited tumour resection.
Entire maxilla removed.
Includes:
Orbit
Adjacent soft tissue
If involved
Indications:
Skull base invasion
Cribriform involvement
Indications:
Extensive orbital invasion
Loss of vision
Extraocular muscle involvement
Advanced tumours
Positive margins
Inoperable disease
Current standard
Advantages:
Better tumour targeting
Less toxicity
Tumour reduction before surgery
Advanced SCC
Metastatic disease
Cisplatin
Carboplatin
5-FU
Taxanes
Selected advanced tumours
(EGFR inhibitor)
For recurrent/metastatic disease
Placed during surgery
After wound healing
Permanent prosthesis
Options:
Fibula flap
Radial forearm flap
Anterolateral thigh flap
Goals:
Speech restoration
Swallowing restoration
Cosmetic rehabilitation
Every 3–6 months initially
CT/MRI/PET-CT
Most recurrences occur within:
Proptosis
Diplopia
Blindness
Meningitis
Brain abscess
CSF leak
Facial deformity
Palatal fistula
Trismus
Lung
Liver
Bone
Early stage
Complete excision
Negative margins
Orbital invasion
Intracranial extension
Nodal metastasis
Distant metastasis
Adenoid cystic perineural spread
5-year survival:
Approximately
depending upon stage.
| Feature | Benign Tumours | Malignant Tumours |
|---|---|---|
| Growth | Slow | Rapid |
| Pain | Usually absent | Common |
| Bone destruction | Rare | Common |
| Epistaxis | Mild | Frequent |
| Orbital involvement | Late | Early |
| Intracranial extension | Rare | Possible |
| Metastasis | Absent | Present |
| Prognosis | Excellent | Variable |
| Feature | Maxillary | Ethmoid |
|---|---|---|
| Frequency | Most common | Second most common |
| Initial symptom | Nasal obstruction | Nasal obstruction |
| Facial swelling | Common | Uncommon |
| Dental symptoms | Common | Rare |
| Orbital symptoms | Late | Early |
| Intracranial spread | Late | Earlier |
| Prognosis | Better | Slightly poorer |
| Feature | Inverted Papilloma | Nasal Polyp |
|---|---|---|
| Laterality | Usually unilateral | Usually bilateral |
| Epistaxis | Common | Rare |
| Bone destruction | May occur | Uncommon |
| Malignant potential | Present | Absent |
| MRI | Cerebriform pattern | Absent |
| Treatment | Surgical excision | Medical + surgery |
| Feature | Suprastructure | Infrastructure |
|---|---|---|
| Location | Above Ohngren line | Below Ohngren line |
| Orbital involvement | Common | Less common |
| Skull base involvement | Common | Rare |
| Surgical difficulty | Greater | Less |
| Prognosis | Poor | Better |
| Feature | CT | MRI |
|---|---|---|
| Bone erosion | Excellent | Poor |
| Soft tissue extent | Moderate | Excellent |
| Orbit | Good | Excellent |
| Intracranial extension | Moderate | Excellent |
| Perineural spread | Poor | Excellent |
| Surgical planning | Excellent | Complementary |
| Feature | Olfactory Neuroblastoma | SNUC |
|---|---|---|
| Origin | Olfactory epithelium | Undifferentiated epithelium |
| Growth | Relatively slower | Very aggressive |
| Histology | Homer-Wright rosettes | Pleomorphic cells |
| Prognosis | Better | Poor |
| Treatment | Surgery + RT | CRT ± Surgery |
✓ Maxillary sinus is the commonest site of PNS malignancy.
✓ Ethmoid sinus tumours commonly present with orbital symptoms.
✓ Sphenoid sinus lesions may involve cranial nerves II, III, IV, V and VI.
✓ Posterior wall of maxillary sinus is related to pterygopalatine fossa.
✓ Roof of maxillary sinus forms floor of orbit.
✓ Wood dust exposure strongly associated with adenocarcinoma.
✓ Leather workers have increased risk of adenocarcinoma.
✓ Smoking is associated with SCC.
✓ Inverted papilloma is the most important premalignant sinonasal lesion.
✓ Most common malignancy = Squamous cell carcinoma.
✓ Most common benign tumour = Osteoma.
✓ Adenoid cystic carcinoma spreads by perineural invasion.
✓ Olfactory neuroblastoma shows Homer-Wright rosettes.
✓ Inverted papilloma shows endophytic growth pattern.
✓ Ground glass appearance = Fibrous dysplasia.
✓ Cerebriform pattern on MRI = Inverted papilloma.
✓ Cribriform plate destruction suggests olfactory neuroblastoma.
✓ CT best for bone erosion.
✓ MRI best for soft tissue spread.
✓ Endoscopic medial maxillectomy is treatment of choice for inverted papilloma.
✓ Craniofacial resection used for skull base involvement.
✓ Orbital exenteration indicated only when orbit extensively involved.
✓ Maxillectomy may require obturator rehabilitation.
✓ Early lesions → surgery.
✓ Advanced lesions → surgery + radiotherapy.
✓ IMRT is current radiotherapy standard.
✓ Immunotherapy useful in recurrent/metastatic disease.
Q. Most common malignant tumour of paranasal sinuses?
A. Squamous cell carcinoma.
Q. Most common site of PNS malignancy?
A. Maxillary sinus.
Q. Most common benign tumour of PNS?
A. Osteoma.
Q. Characteristic MRI feature of inverted papilloma?
A. Cerebriform pattern.
Q. Histological hallmark of olfactory neuroblastoma?
A. Homer-Wright rosettes.
Q. Ground glass appearance is seen in?
A. Fibrous dysplasia.
Q. Premalignant sinonasal lesion?
A. Inverted papilloma.
Q. Commonest occupational association with adenocarcinoma?
A. Wood dust exposure.
Q. Tumour famous for perineural spread?
A. Adenoid cystic carcinoma.
Q. Classification used for olfactory neuroblastoma?
A. Kadish classification.
Q. What is Ohngren's line?
A. Imaginary line from medial canthus to angle of mandible dividing maxillary sinus into suprastructure and infrastructure.
Q. Why is suprastructure prognosis poor?
A. Early orbital and skull base involvement.
Q. What is Lederman classification?
A. Division into anterior and posterior lesions based on prognosis.
Q. What is treatment of inverted papilloma?
A. Endoscopic medial maxillectomy.
Q. Which sinus tumour commonly causes proptosis?
A. Ethmoid sinus carcinoma.
Q. What is the origin of olfactory neuroblastoma?
A. Olfactory neuroepithelium.
Q. What is the radiological appearance of fibrous dysplasia?
A. Ground glass appearance.
Q. Which tumour commonly spreads along nerves?
A. Adenoid cystic carcinoma.
Q. What is orbital exenteration?
A. Removal of orbital contents for extensive orbital invasion.
Q. Which investigation is best for bone destruction?
A. CT scan.
• Commonest PNS malignancy = SCC.
• Commonest site = Maxillary sinus.
• Most important premalignant lesion = Inverted papilloma.
• MRI cerebriform pattern = Inverted papilloma.
• Ground glass CT = Fibrous dysplasia.
• Homer-Wright rosettes = Olfactory neuroblastoma.
• Perineural spread = Adenoid cystic carcinoma.
• Kadish staging = Olfactory neuroblastoma.
• Poor prognosis = Suprastructure maxillary tumour.
• Best investigation for bone erosion = CT.
Maxillary sinus anatomy
Ethmoid sinus anatomy
Frontal sinus anatomy
Sphenoid sinus anatomy
Orbit-sinus relations
Skull base relations
Pterygopalatine fossa
Infratemporal fossa
Cranial nerve relations
Local spread pathways
Orbital extension
Intracranial extension
Perineural spread
Lymphatic spread
Hematogenous spread
Ohngren's line
Suprastructure
Infrastructure
Lederman classification
Anterior lesions
Posterior lesions
Inverted papilloma
Endophytic growth
Malignant transformation
Olfactory neuroblastoma
Cribriform plate involvement
Intracranial extension
Fibrous dysplasia
Ground glass bone
Facial asymmetry
Juvenile ossifying fibroma
Bone expansion
Orbital displacement
Medial maxillectomy
Partial maxillectomy
Total maxillectomy
Radical maxillectomy
Craniofacial resection
Orbital exenteration
Obturator prosthesis
Free flap reconstruction
Rehabilitation
CT maxillary carcinoma
Bone destruction
Orbital invasion
MRI orbital extension
MRI intracranial extension
MRI perineural spread
MRI cerebriform pattern
Fibrous dysplasia CT
PET-CT metastasis
Students must recognize:
CT maxillary sinus carcinoma.
CT ethmoid sinus carcinoma.
CT orbital invasion.
CT skull base destruction.
MRI intracranial extension.
MRI perineural spread.
MRI cerebriform pattern of inverted papilloma.
MRI olfactory neuroblastoma.
Ground glass appearance of fibrous dysplasia.
PET-CT showing nodal metastasis.
PET-CT recurrence.
Post-maxillectomy imaging.
Key Finding:
Keratin pearls
Intercellular bridges
Exam Importance:
Commonest malignancy
Key Finding:
Broad pushing margins
Well differentiated squamous epithelium
Exam Importance:
Low metastatic potential
Key Finding:
Gland formation
Mucin production
Exam Importance:
Wood dust association
Key Finding:
Cribriform pattern
Swiss cheese appearance
Exam Importance:
Perineural invasion
Key Finding:
Pleomorphic undifferentiated cells
Necrosis
Exam Importance:
Highly aggressive tumour
Key Finding:
Homer-Wright rosettes
Exam Importance:
Diagnostic hallmark
Key Finding:
Endophytic growth
Exam Importance:
Premalignant lesion
Key Finding:
Chinese letter trabeculae
Exam Importance:
Ground glass CT correlation
Key Finding:
Dense mature lamellar bone
Exam Importance:
Commonest benign tumour
Key Finding:
Malignant cartilage cells
Exam Importance:
Rare malignant tumour
Key Finding:
Strap cells
Cross striations
Exam Importance:
Common paediatric sarcoma
Key Finding:
Monomorphic lymphoid cells
Exam Importance:
Differential diagnosis
Key Finding:
Melanin pigment
Pleomorphic melanocytes
Exam Importance:
Poor prognosis
Cheek swelling due to maxillary carcinoma.
Facial asymmetry.
Palatal bulge.
Loose upper molar teeth.
Trismus.
Proptosis due to ethmoid tumour.
Diplopia.
Cervical nodal metastasis.
Endoscopic sinonasal tumour.
Inverted papilloma endoscopic appearance.
Obturator prosthesis.
Post-maxillectomy cavity.
CT maxillary carcinoma.
MRI orbital invasion.
MRI intracranial extension.
PET-CT metastasis.
✓ Most common PNS malignancy = SCC.
✓ Most common site = Maxillary sinus.
✓ Most important premalignant lesion = Inverted papilloma.
✓ Cerebriform MRI = Inverted papilloma.
✓ Ground glass CT = Fibrous dysplasia.
✓ Homer-Wright rosettes = Olfactory neuroblastoma.
✓ Perineural spread = Adenoid cystic carcinoma.
✓ Poor prognosis = Suprastructure lesions.
✓ CT = Bone destruction.
✓ MRI = Soft tissue extension.
✓ Kadish staging = Olfactory neuroblastoma.
✓ Endoscopic medial maxillectomy = Treatment of inverted papilloma.
| Topic | High Yield Fact |
|---|---|
| Commonest site | Maxillary sinus |
| Commonest malignancy | SCC |
| Premalignant lesion | Inverted papilloma |
| MRI cerebriform pattern | Inverted papilloma |
| Ground glass CT | Fibrous dysplasia |
| Rosettes | Olfactory neuroblastoma |
| Perineural spread | Adenoid cystic carcinoma |
| Poor prognosis | Suprastructure tumour |
| Bone destruction | CT scan |
| Soft tissue spread | MRI |
| Occupational association | Wood dust → Adenocarcinoma |
| Staging | Kadish classification |
Discuss carcinoma maxillary sinus.
Explain Ohngren's classification.
Describe inverted papilloma.
Olfactory neuroblastoma.
Fibrous dysplasia.
Classification of sinonasal tumours.
Occupational carcinogens causing sinonasal cancer.
CT and MRI findings in PNS tumours.
Management of maxillary sinus carcinoma.
Reconstruction after maxillectomy.
END OF CHAPTER 40
NEOPLASMS OF PARANASAL SINUSES
MedMentor EDU ENT Notes
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