Route and spread of maxillary carcinoma 10 marks answer for ms ent exam

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Route and Spread of Maxillary Carcinoma

Introduction

Carcinoma of the maxillary sinus (antrum) is the most common sinonasal malignancy, accounting for approximately 55% of all sinonasal tumours. Squamous cell carcinoma is the predominant histological type. A defining feature of this tumour is late presentation - only 25% of maxillary sinus carcinomas are confined within the antrum at the time of diagnosis, making understanding of spread patterns clinically essential.

Ohngren's Line - Prognostic Division of Spread

Described in 1933, Ohngren's line runs from the medial canthus of the eye to the angle of the mandible. It divides the maxillary sinus into:

Suprastructure (above the line): Tumours here spread towards the orbit, skull base, pterygoid plates and infratemporal fossa - worse prognosis, less resectable
Infrastructure (below the line): Tumours spread towards the oral cavity, alveolus and palate - better prognosis, more amenable to surgery

1. Local / Direct Spread

Sinonasal carcinomas first fill the antrum before eroding bony walls. Periosteum and dura act as temporary barriers, but thin bone (anterior maxilla, orbital floor) is readily destroyed.

Direction	Structures Involved	Clinical Features
Medially	Lateral nasal wall, nasal cavity	Nasal obstruction, epistaxis, unilateral discharge
Laterally	Cheek, buccal sulcus	Cheek swelling, skin ulceration (see image below)
Superiorly	Orbital floor, inferior orbital fissure, orbit	Proptosis, diplopia, epiphora, infraorbital paraesthesia
Inferiorly	Hard palate, alveolus	Loose teeth, palatal swelling, oro-antral fistula
Posteriorly	Infratemporal fossa, pterygopalatine fossa, pterygoid plates	Trismus (key sign), referred otalgia
Posterosuperiorly	Skull base, cavernous sinus, middle cranial fossa	Cranial nerve palsies, intracranial extension

Advanced carcinoma of maxillary antrum - tumour has breached the lateral wall presenting as cheek swelling

Advanced carcinoma of the maxillary antrum. The tumour has breached the lateral wall and presents as a swelling in the cheek. (Scott-Brown's Otorhinolaryngology)

Coronal MRI showing extensive left maxillary antral carcinoma invading the orbit and adjacent structures

Coronal MRI: Extensive left maxillary antral carcinoma invading adjacent structures including the orbit. (Bailey & Love's)

2. Perineural Spread

This is a clinically important route, particularly in adenoid cystic carcinoma but also in SCC:

Greater palatine nerve - from palatal tumours, spread travels superiorly through the greater palatine foramen into the pterygopalatine fossa
Infraorbital nerve (V2 branch of trigeminal) - infraorbital paraesthesia / numbness of the cheek is an early warning sign of nerve involvement
Maxillary division of trigeminal (V2) - can carry tumour intracranially through the foramen rotundum to the Meckel's cave and cavernous sinus

3. Regional Lymphatic Spread

The lymphatic drainage of the maxillary sinus is relatively sparse. Two pathways exist:

Anterior pathway: Anteroinferior nasal cavity and nasal vestibule drain to facial, parotid, and submandibular nodes, then to the upper deep cervical chain.

Posterior pathway: The remainder of the nose and paranasal sinuses drain anteriorly to the Eustachian tube to retropharyngeal nodes (first echelon), then to the upper deep cervical chain.

Key points for the exam:

Lymph node spread occurs in 25-35% of patients at some point during disease
Only ~10% present with nodal disease at diagnosis (marker of locally advanced disease)
Submandibular and jugulodigastric nodes are most commonly involved
Bilateral nodal involvement can occur with midline-extending tumours
The relatively scant lymphatic supply explains why nodal disease is a late feature

4. Distant (Haematogenous) Spread

Distant metastases are uncommon at presentation. They occur in:

~20% of adenocarcinomas
~10% of squamous cell carcinomas
Usually associated with local recurrence
Common sites: lungs, liver, bone

Clinical Correlations - Signs Indicating Route of Spread

Sign / Symptom	Route / Structure Involved
Cheek swelling	Lateral wall erosion
Nasal obstruction / epistaxis	Medial spread into nasal cavity
Epiphora, proptosis, diplopia	Superior spread into orbit
Infraorbital anaesthesia / paraesthesia	Infraorbital nerve (V2) involvement
Trismus	Posterior spread to pterygoid muscles / infratemporal fossa
Loose upper teeth / oro-antral fistula	Inferior spread to alveolus/palate
Cervical lymphadenopathy	Regional lymphatic spread (late sign)
Headache / CN palsies	Skull base / cavernous sinus extension

Summary Points for 10-mark Answer

Maxillary carcinoma spreads in six directions - medial, lateral, superior, inferior, posterior, and posterosuperior
Ohngren's line separates suprastructure (worse prognosis) from infrastructure tumours
Only 25% are confined to the antrum at presentation - late presentation is characteristic
Perineural spread (especially along V2 and greater palatine nerve) is a route to skull base
Lymph node metastasis is relatively late (10% at presentation); submandibular and jugulodigastric nodes are first involved; retropharyngeal nodes drain the posterior pathway
Trismus = posterior spread (pterygoids); infraorbital paraesthesia = nerve involvement; proptosis = orbital invasion
Distant metastases are uncommon and more frequent in adenocarcinoma than SCC

Sources: Scott-Brown's Otorhinolaryngology Head & Neck Surgery; Bailey and Love's Short Practice of Surgery, 28th ed.; Cummings Otolaryngology Head and Neck Surgery

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