Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumour arising from the lining of the nasopharynx, classically from the fossa of Rosenmüller. It is a perennial NEET PG favourite because of its tight links to the Epstein–Barr virus (EBV), its unique geographic and racial distribution, its early silent spread to neck nodes, and the eponymous Trotter's triad. Unlike most head-and-neck squamous cancers, NPC is treated primarily by radiotherapy, not surgery.

Definition and surgical anatomy

The nasopharynx is the cuboidal space behind the nasal cavity, above the soft palate, communicating anteriorly with the nasal cavity through the choanae and inferiorly with the oropharynx. The key landmark is the fossa of Rosenmüller (pharyngeal recess) — a slit-like recess situated posterosuperior to the torus tubarius (the cartilaginous elevation of the Eustachian tube opening). This is the commonest site of origin of NPC and explains many of its early symptoms.

High-yield: The fossa of Rosenmüller is the most common site of origin of nasopharyngeal carcinoma. Its proximity to the Eustachian tube explains the early unilateral serous otitis media (conductive deafness) seen in adults — unilateral middle-ear effusion in an adult is NPC until proven otherwise.

The roof of the nasopharynx is related to the body of the sphenoid and the floor of the middle cranial fossa; lateral spread reaches the foramen lacerum and cavernous sinus, accounting for cranial-nerve involvement.

Epidemiology — why it is "exam-special"

Feature	Detail (commonly tested)
Geographic hotspots	Southern China (Guangdong/Canton — "Canton tumour"), Hong Kong, Southeast Asia, North Africa, Inuit/Eskimos of the Arctic, Mediterranean basin
Indian relevance	Higher in North-East India (Nagaland, Manipur, Mizoram)
Age	Bimodal — small peak in adolescence (15–25 yrs) and larger peak at 50–60 yrs
Sex	Male : female ≈ 2–3 : 1
Diet	Salted fish (Cantonese), nitrosamine-rich preserved foods
Genetics	HLA-A2, HLA-Bw46 association; familial clustering
Virus	Epstein–Barr virus (near-universal in undifferentiated type)

High-yield: NPC is the commonest malignant tumour of the nasopharynx and the commonest head-and-neck cancer associated with EBV.

Etiology and pathophysiology

NPC is multifactorial — a combination of viral, environmental/dietary, and genetic factors.

1. EBV — The strongest association is with the undifferentiated (WHO type III) carcinoma, in which EBV genome (EBER, LMP-1, EBNA) is consistently demonstrated in tumour cells. EBV drives epithelial transformation; circulating EBV-DNA load correlates with tumour burden and is used for monitoring.
2. Dietary nitrosamines — Cantonese-style salted fish, especially consumed in childhood, is a classic exam answer. Preserved/fermented foods rich in volatile nitrosamines act as carcinogens.
3. Genetic susceptibility — HLA haplotypes (HLA-A2, B-sin2/Bw46), familial aggregation, and chromosomal deletions (3p, 9p, 14q).
4. Environmental — Smoke from wood fires, formaldehyde, occupational dust; tobacco/alcohol play a smaller role than in other head-and-neck SCC.

Pathway: EBV infection + genetic predisposition + dietary nitrosamines → epithelial dysplasia of fossa of Rosenmüller → invasive carcinoma → early submucosal lateral spread → cervical nodal metastasis (often the presenting feature) → skull-base/cranial nerve invasion → distant spread (bone > lung > liver).

WHO histological classification

This is one of the most frequently asked single facts in ENT.

WHO type	Name	Keratin	EBV link	Radiosensitivity / prognosis
Type I	Keratinising squamous cell carcinoma	Present	Weak / inconsistent	Least radiosensitive, worst prognosis; more in Western/older patients
Type II	Non-keratinising (differentiated) carcinoma	Absent	Strong	Intermediate
Type III	Undifferentiated carcinoma (lymphoepithelioma, Regaud/Schmincke pattern)	Absent	Strongest	Most radiosensitive, but often presents with nodal/distant spread; commonest type overall and in endemic areas

High-yield: The undifferentiated carcinoma (WHO type III / lymphoepithelioma) is the commonest histological subtype, has the strongest EBV association, and is the most radiosensitive. "Lymphoepithelioma" refers to the abundant non-neoplastic lymphocytic infiltrate intermixed with tumour cells (the lymphocytes are reactive, not malignant). Regaud type = compact cell nests; Schmincke type = diffuse scattered cells.

Clinical features

NPC is notorious for presenting late because the primary tumour is hidden and early symptoms are vague. Symptoms are grouped by direction of spread.

1. Nasal: nasal obstruction, blood-stained nasal discharge, epistaxis.

2. Aural (Eustachian tube blockage): unilateral conductive hearing loss, tinnitus, sensation of blocked ear, recurrent serous otitis media. → Unilateral OME in an adult mandates nasopharyngeal examination.

3. Cervical (nodal): A painless upper-neck mass (level II / jugulodigastric and posterior triangle nodes) is the commonest presenting symptom — present in up to 60–90% at diagnosis. The node of Rouvière (lateral retropharyngeal node) is the first echelon.

4. Neurological (skull-base/cranial-nerve spread): headache, diplopia, facial numbness, ophthalmoplegia. Cranial nerves III–VI are affected via the cavernous sinus/foramen lacerum (petrosphenoidal/Jacod's syndrome), and IX–XII via the parapharyngeal/retropharyngeal space (retroparotidal/Villaret's syndrome).

High-yield — Trotter's triad (sinus of Morgagni syndrome), a classic NEET PG recall, comprises:

1. Conductive deafness (Eustachian tube obstruction)
2. Ipsilateral palatal palsy / immobility (involvement of the mandibular nerve / soft-palate motor supply)
3. Trigeminal neuralgia / pain in the side of the head and face (V3 involvement) Trismus may be added. It results from tumour spreading laterally through the sinus of Morgagni (the gap in the pharyngobasilar fascia transmitting the Eustachian tube and levator palati).

Mnemonic for Trotter's triad — "Deaf Palate Trigeminal" (DPT): Deafness (conductive), Palatal palsy, Trigeminal neuralgia.

High-yield: NPC may present with metastasis from an unknown primary — an enlarged neck node with no obvious source should prompt a nasopharyngeal biopsy. It is a leading cause of occult primary in the head and neck, especially with cystic level II nodes.

Diagnosis and investigation of choice

Stepwise approach:

Nasopharyngoscopy (visualise fossa of Rosenmüller) → Endoscopic biopsy of the primary (investigation/diagnosis of choice — gives histology) → Contrast-enhanced MRI of the nasopharynx and skull base (best imaging for soft-tissue and skull-base extent, perineural/parapharyngeal spread) → CT for bony erosion of the skull base → FNAC of neck node if a node is the only accessible lesion → PET-CT for distant metastasis/staging → EBV serology and plasma EBV-DNA for support and monitoring.

High-yield: Endoscopic biopsy of the nasopharyngeal primary is the definitive diagnostic investigation. MRI is the imaging modality of choice (superior soft-tissue contrast, detects perineural spread). Open biopsy of a neck node is to be avoided — it can compromise subsequent radiotherapy fields and worsen outcome; do FNAC instead.

EBV serology and markers

Marker	Significance
IgA anti-VCA (viral capsid antigen)	Most useful serological screening test; raised IgA-VCA is the classic exam answer, used for early detection in endemic populations
IgA anti-EA (early antigen)	Correlates with tumour activity
EBNA antibodies	Marker of past infection
Plasma EBV-DNA (cell-free)	Best for prognosis, monitoring response, and detecting recurrence; high levels = worse prognosis

High-yield: Raised serum IgA antibody to EBV viral capsid antigen (IgA-VCA) is the screening serological marker, and plasma EBV-DNA is the marker for monitoring treatment response and recurrence.

Staging (essentials)

NPC uses the AJCC TNM system. Salient, examinable points:

• T1 confined to nasopharynx/nasal cavity/oropharynx; T2 parapharyngeal extension; T3 bony skull base/sinuses; T4 intracranial, cranial nerves, orbit, hypopharynx.
• N staging is unique — nodal level relative to the caudal border of cricoid and laterality/size matter; bilateral nodes are common and do not by themselves preclude cure.
• Even advanced local/nodal disease (without distant mets) is potentially curable because of high radiosensitivity.

Management — radiotherapy is the mainstay

High-yield: Radiotherapy is the primary/definitive treatment of choice for NPC. The reasons: (a) tumours (esp. WHO III) are highly radiosensitive; (b) the anatomical site is surgically inaccessible; (c) bilateral and retropharyngeal nodal spread is best covered by radiation fields. Surgery is not the primary modality.

Treatment by stage (flow):

1. Early (Stage I): Radiotherapy alone — external beam, preferably Intensity-Modulated Radiotherapy (IMRT) to the nasopharynx + bilateral neck (elective nodal irradiation because of high occult-node rate).
2. Locally advanced (Stage II–IVA): Concurrent chemoradiotherapy (radiotherapy + cisplatin) ± induction or adjuvant chemotherapy. Cisplatin-based chemo improves survival.
3. Metastatic / recurrent (Stage IVB): Platinum-based palliative chemotherapy (cisplatin + gemcitabine/5-FU); immunotherapy (PD-1 inhibitors) in recurrent/metastatic disease in modern protocols.

Role of surgery — limited:

• Neck dissection for residual/recurrent nodal disease after radiotherapy.
• Nasopharyngectomy (salvage) for localised radio-resistant or recurrent primary.

High-yield: Drug of choice for chemoradiation = cisplatin (concurrent). IMRT is preferred to conventional RT because it spares the parotid (less xerostomia), brainstem, optic apparatus, and temporal lobes.

Complications

Of the disease:

• Cranial nerve palsies (Jacod's/Villaret's syndromes), trismus.
• Distant metastasis — bone (commonest) > lung > liver (NPC has the highest distant-metastasis rate among head-and-neck cancers).

Of radiotherapy (frequently asked):

• Xerostomia (parotid damage) — commonest chronic morbidity.
• Mucositis, dysgeusia, dental caries.
• Osteoradionecrosis of the mandible/skull base.
• Trismus (masticator-muscle fibrosis), hypothyroidism.
• Radiation-induced temporal-lobe necrosis, optic neuropathy, hearing loss.
• Post-radiation second malignancy.

Key differential diagnoses

Condition	Distinguishing pointer
Juvenile nasopharyngeal angiofibroma (JNA)	Adolescent male, profuse recurrent epistaxis, highly vascular; biopsy contraindicated; characteristic Holman–Miller sign (anterior bowing of posterior maxillary wall) and widening of pterygopalatine fossa on imaging
Nasopharyngeal lymphoma	Younger, bulky lymphoid mass, systemic "B" symptoms; histology + IHC differentiate
Tornwaldt's cyst / adenoid hypertrophy	Benign midline; adenoids common in children, regress with age
Chordoma / skull-base tumour	Midline clival mass on imaging
Rhabdomyosarcoma	Children, embryonal type in nasopharynx
Tuberculosis of nasopharynx	Granulomatous; caseating nodes; supportive of ENT TB elsewhere

High-yield differential: In an adolescent male with recurrent epistaxis and a nasopharyngeal mass — think JNA, and never biopsy (risk of torrential bleed). In an adult with a neck node, blocked ear, and epistaxis — think NPC, and biopsy the primary.

Recently asked / exam angle

• Trotter's triad components — conductive deafness + ipsilateral palatal palsy + trigeminal neuralgia (one-liner recall, asked repeatedly).
• Commonest site of origin = fossa of Rosenmüller (pharyngeal recess).
• Commonest presenting symptom = painless neck (cervical lymph) node enlargement.
• WHO type III (undifferentiated/lymphoepithelioma) — most common, strongest EBV link, most radiosensitive.
• Investigation/serology: raised IgA-VCA; plasma EBV-DNA for monitoring; MRI = imaging of choice; endoscopic biopsy = diagnosis of choice.
• Treatment of choice = radiotherapy (concurrent cisplatin chemoradiation for advanced disease); surgery has a limited/salvage role.
• Unilateral serous otitis media in an adult → rule out NPC.
• First-echelon node = node of Rouvière (retropharyngeal).
• Avoid open neck-node biopsy before treating the primary.
• Cranial-nerve syndromes: Jacod's (III–VI, superior orbital fissure/cavernous) vs Villaret's (IX–XII, retroparotid).
• High distant-metastasis rate among head-neck cancers; bone is the commonest distant site.

Rapid revision

1. NPC arises commonly from the fossa of Rosenmüller, posterosuperior to the torus tubarius.
2. Strongest aetiological associations: EBV, Cantonese salted fish, HLA-A2/Bw46 genetics.
3. WHO type III (undifferentiated/lymphoepithelioma) — commonest, strongest EBV link, most radiosensitive; type I (keratinising) is least radiosensitive with worst prognosis.
4. Commonest presentation = painless upper-deep-cervical lymph node; NPC is a top cause of head-neck occult primary.
5. Unilateral conductive deafness / serous otitis media in an adult is NPC until proven otherwise.
6. Trotter's triad = conductive deafness + ipsilateral palatal palsy + trigeminal neuralgia (lateral spread via sinus of Morgagni).
7. Diagnosis of choice = endoscopic biopsy of the primary; imaging of choice = MRI; CT for bony skull-base erosion.
8. IgA-VCA = screening serology; plasma EBV-DNA = monitoring/prognosis marker.
9. Avoid open biopsy of neck nodes (do FNAC); it worsens radiotherapy outcome.
10. Radiotherapy (IMRT) is the treatment of choice; concurrent cisplatin chemoradiation for locally advanced disease.
11. Surgery is reserved for salvage nasopharyngectomy and neck dissection of residual nodes.
12. Commonest distant metastasis = bone; commonest chronic RT complication = xerostomia; watch for temporal-lobe necrosis and osteoradionecrosis.