Nasopharyngeal carcinoma.
1. Definition: Nasopharyngeal Carcinoma is a malignant tumor arising from the epithelial lining of the nasopharynx, most commonly from the Fossa of Rosenmüller (the pharyngeal recess found posterior to the opening of the Eustachian tube).
It is most often a non-keratinizing squamous cell carcinoma.
2. Etiopathogenesis - NPC is multifactorial.
- Viral Factor: Strong association with the Epstein-Barr Virus (EBV). The virus remains in a latent state within the nasopharyngeal epithelial cells.
- Dietary/Environmental Factors: Consumption of salted fish and fermented foods containing nitrosamines. Early childhood exposure is particularly significant.
- Genetic Susceptibility: Strong HLA-type associations (eg, HLA-A2, B13) explain the high incidence in specific ethnic groups (Cantonese).
- Smoking + Alcohol
- More -males
Pathogenesis
- EBV infects nasopharyngeal epithelial cells
- Viral oncogenes promote malignant transformation
- Early submucosal spread
- Early lymphatic dissemination to retropharyngeal and cervical nodes
- Late hematogenous spread (bone, lung, liver)
3. Classification (WHO)
- 1. Type I (Keratinizing SCC): Most similar to other head and neck cancers; associated with smoking; less sensitive to radiation.
- 2. Type II (Non-keratinizing differentiated): Intermediate behavior.
- 3. Type III (Undifferentiated): The most common type; strongly associated with EBV; high rate of distant metastasis. Nasal endoscopy.
4. Clinical Picture - NPC presents late and insidiously. TRIAD
- Nasal Symptoms: Nasal obstruction(usually unilateral) , post-nasal drip, and epistaxis (often blood-stained nasal discharge).
- Otological Symptoms: Unilateral conductive hearing loss and serous otitis media due to Eustachian tube obstruction. In an adult with persistent unilateral middle ear effusion, NPC must be ruled out.
- Neurological (Advanced Disease): Cranial nerve palsies (CN III, IV, VI leading to diplopia; CN V leading to facial
pain/numbness). Trotter's Triad is a classic exam finding: 1. Conductive hearing loss, 2. Ipsilateral facial/palatal neuralgia (CN V), 3. Palatal paralysis (CN X).
- Neck Mass: most common presentation, Metastasis usually occurs to Level II, III, and V lymph nodes, often bilateral
- 3⃣ Cervical lymph nodes
- Painless neck mass
- Often first presenting sign
5. Paraclinical and Radiological Examinations
- Nasopharyngoscopy + Biopsy from fossa of Rosenmüller: Direct visualization of the tumor
- Nasal endoscopy
- Serology: Measurement of EBV DNA titers and IgA antibodies against Viral Capsid Antigen (VCA).
- MRI (Preferred): Best for assessing skull base invasion, intracranial spread, and soft tissue involvement.
- CT: Useful for evaluating bone destruction of the clivus or foramen lacerum.
- PET-CT: Used to screen for distant metastases (bone, lung, liver).
6. Treatment Options – primarily non-surgical disease due to its anatomical location and high radiosensitivity.
- Early Stage (I): Definitive Radiotherapy alone.