Nasopharyngeal Carcinoma

Slide 1 · Nasopharyngeal Carcinoma

Epidemiology · EBV association · Histopathology · Clinicopathologic correlation

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Describe the geographic and environmental associations of nasopharyngeal carcinoma.

Recognize the WHO histologic subtypes and hallmark nonkeratinizing morphology.

Explain tissue EBV testing and its distinction from circulating EBV assays.

Integrate clinical presentation, diagnostic workup, and histology-related treatment response.

Slide 3 · Disease definition and scope

A malignant epithelial tumor arising from the nasopharyngeal mucosa.

The major carcinomas show squamous differentiation, with variable keratinization.

The disease is biologically distinctive because of geography, lymphoid-rich tissue, and EBV association.

Slide 4 · Where the nasopharynx fits

NASOPHARYNX

OROPHARYNX

HYPOPHARYNX

Posterior to the nasal cavity

Adjacent lymphoid tissue and cervical lymphatic drainage

Original teaching schematic — not a diagnostic specimen

Slide 5 · Four recurring features of nasopharyngeal carcinoma

Geography

Marked regional variation, including endemic populations in southern China and Southeast Asia.

Lymphoid microenvironment

Carcinoma cells frequently coexist with abundant reactive lymphocytes.

Epstein–Barr virus

Strong tumor-associated EBV signal is typical of nonkeratinizing NPC.

Clinical nodal disease

Cervical nodal metastasis may be prominent even when nasal symptoms are modest.

Slide 6 · Geographic distribution: High-incidence regions

Southern China

A major endemic region highlighted by the primary textbook.

Southeast Asia

Several populations have high NPC burden.

North Africa

The disease is geographically enriched in parts of this region.

Arctic Indigenous populations

Inuit populations in Alaska and Canada are specifically noted.

Slide 7 · Why geographic epidemiology matters

Geographic clustering changes the pretest probability of NPC in relevant clinical settings.

Marked variation implies that infection alone does not fully explain risk.

Population-level associations must not be treated as diagnostic criteria for an individual patient.

Slide 8 · Exposure patterns linked to NPC

Diet-associated risks

Salted fish and fermented foods are cited in high-exposure diets.

Nitrosamines are implicated in preserved food exposures.

Environmental insults

Tobacco smoking is listed as an associated exposure.

Chemical fumes are another cited environmental exposure.

Slide 9 · EBV infection is associated with—rather than synonymous with—NPC

EBV is closely associated with nonkeratinizing NPC.

Many individuals acquire EBV without developing nasopharyngeal carcinoma.

Risk is multifactorial: Viral, environmental, and host-related factors may act together.

Slide 10 · Multifactorial etiologic model

Viral association

EBV in malignant epithelial cells

Environmental exposure

Preserved foods, tobacco, and chemical fumes

Host and population context

Regional and individual susceptibility

Interacting associations — no fixed sequence or single sufficient cause

Conceptual schematic; Contribution of each factor varies across populations

Slide 11 · Why tumor-associated EBV is distinctive

EBV can be detected in malignant epithelial cells in nonkeratinizing carcinoma.

A lymphoid-rich background does not itself establish EBV-driven carcinoma.

Tissue localization is important: EBV must be interpreted in the tumor-cell compartment.

Slide 12 · EBV tissue detection: The principle of EBER in situ hybridization

EBV-encoded small RNAs (EBERs) can be demonstrated by in situ hybridization.

A positive signal localized to malignant epithelial nuclei supports EBV-associated NPC.

The test helps distinguish true EBV-positive tumor cells from EBV-bearing bystander lymphocytes.

Slide 13 · EBV serology: Key Principles

Patients with nonkeratinizing NPC often show antibodies to EBV early antigens.

Antibodies to viral capsid antigens may also be present.

Serologic association is not equivalent to proving EBV within the tumor tissue.

Slide 14 · Circulating EBV DNA: Blood-based tumor marker context

PCR detection of EBV DNA in blood serum.

Contemporary clinical pathways commonly use pretreatment plasma EBV DNA as a biomarker.

Blood viral DNA testing complements, but does not replace, histopathologic diagnosis.

Slide 15 · Three EBV-related laboratory approaches

Assay

Specimen

Main interpretation

EBER in situ hybridization

Tumor biopsy

Localizes latent EBV RNA to lesional cells

EBV antibody serology

Blood

Evidence of immune response; Limited tissue specificity

EBV DNA PCR

Serum or plasma

Circulating viral DNA biomarker; Contextualize clinically

Slide 16 · What constitutes strong diagnostic evidence?

Morphologically malignant epithelial cells are the primary diagnostic evidence.

Demonstrated epithelial lineage helps exclude a primary hematolymphoid neoplasm.

EBER positivity in the tumor-cell nuclei supports EBV-associated NPC.

Slide 17 · Current histologic classification

Subtype

Characteristic morphology

Keratinizing squamous cell carcinoma

Squamous differentiation with keratinizing phenotype

Nonkeratinizing squamous cell carcinoma

Less apparent squamous maturation; Often lymphoid-rich

Basaloid squamous cell carcinoma

Basaloid SCC phenotype; Rare in this site

Slide 18 · Classification hierarchy

Nasopharyngeal carcinoma

Keratinizing SCC

Nonkeratinizing SCC

Basaloid SCC

Differentiated or undifferentiated appearance

Classification branches; Not a temporal progression

Slide 19 · Historical terminology: Why it should be avoided

“Lymphoepithelioma” and “lymphoepithelial carcinoma” are legacy labels.

The names reflect conspicuous lymphoid infiltration but may obscure epithelial tumor identity.

Use contemporary WHO histologic subtype terminology in pathology reporting.

Slide 20 · Keratinizing versus nonkeratinizing NPC

Keratinizing type

Resembles keratinizing SCC at other mucosal sites.

Squamous differentiation is conspicuous.

Shows less favorable radiation response in the Robbins discussion.

Nonkeratinizing type

Large epithelial tumor cells may look syncytial.

Prominent nonneoplastic T-cell-rich infiltrate is typical.

Strong EBV association and relative radiosensitivity.

Slide 21 · Keratinizing carcinoma: Morphologic recognition

Histology resembles differentiated squamous cell carcinoma elsewhere in the head and neck.

Identify overt squamous differentiation and keratin formation where present.

Avoid labeling a carcinoma “keratinizing” solely from location or clinical context.

Slide 22 · Keratinizing differentiation: Conceptual drawing

Squamous nests

Central keratinization

Illustrative epithelial differentiation; Not a photomicrograph

Original teaching schematic — not a diagnostic specimen

Slide 23 · Nonkeratinizing carcinoma: Defining cytologic phenotype

Large malignant epithelial cells occur in nests, sheets, or less well-demarcated aggregates.

Nuclei are typically round or oval and vesicular, often with conspicuous nucleoli.

Indistinct cell borders produce the appearance of multinuclear continuity (syncytium).

Slide 24 · Vesicular nuclei and conspicuous nucleoli

Open-appearing chromatin produces the vesicular nuclear appearance.

Prominent nucleoli are a clue to the large malignant epithelial population.

These features must be judged alongside invasion, epithelial lineage, and the inflammatory context.

Slide 25 · Syncytial appearance: What it actually means

Individual tumor-cell borders are difficult to resolve on H&E.

Adjacent epithelial cells therefore appear to form a continuous sheet.

Syncytial morphology is a visual descriptor, not proof of cell fusion or a specific molecular mechanism.

Slide 26 · Nonkeratinizing carcinoma and lymphocytes

Tumor epithelial nuclei

Indistinct cell borders → syncytial appearance

Small infiltrating T lymphocytes (non-neoplastic)

Original teaching schematic — not a diagnostic specimen

Slide 27 · Tumor-associated lymphocytes are predominantly reactive

The lymphoid infiltrate is often abundant and normal in cytologic appearance.

A predominant T-cell component.

Large epithelial tumor cells—not the small lymphocytes—constitute the carcinoma.

Slide 28 · Tumor population versus reactive lymphocytes

Carcinoma cells

Larger cells with vesicular nuclei and prominent nucleoli.

Epithelial lineage demonstrable by cytokeratin expression.

Tumor-cell EBER positivity is diagnostically informative.

Lymphocytes

Generally smaller with denser nuclear chromatin.

Primarily T-cell-rich reactive infiltrate in classic tumors.

Their presence does not convert the lesion into lymphoma.

Slide 29 · Morphologic patterns within nonkeratinizing NPC

Cohesive epithelial islands

Recognizable nests may remain distinct from the lymphoid stroma.

Diffuse admixture

Malignant cells may be interspersed with dense lymphocytes.

Cytologic continuity

Vesicular nuclei and indistinct borders remain recurring clues.

Interpretation

Patterns vary; Adequate recognition of epithelial tumor cells is essential.

Slide 30 · Why a lymphocyte-rich carcinoma can resemble lymphoma

Diffuse lymphocytic admixture may dominate a small or crushed biopsy.

Poorly demarcated epithelial tumor cells may be overlooked.

A lineage-directed panel and EBER localization help resolve the mimic.

Slide 31 · EBER: Localization to epithelial tumor nuclei

EBER nuclear signal

In-situ hybridization localizes viral RNA inside malignant epithelial cells

Original teaching schematic — not a diagnostic specimen

Slide 32 · EBER versus LMP1: Different analytic targets

EBER in situ hybridization detects EBV-encoded RNA in tissue sections.

LMP1 immunohistochemistry detects an EBV-associated protein.

Do not assume LMP1 staining must be present in every EBV-associated carcinoma; EBER is the standard tissue assay.

Slide 33 · Practical interpretation of EBER staining

Confirm nuclear signal in unequivocally malignant epithelial cells.

Account for the possibility of positive background lymphoid cells.

A negative or technically limited result requires correlation with morphology and assay controls.

Slide 34 · Epithelial lineage: Why cytokeratins matter

Pan-cytokeratin positivity supports epithelial differentiation in a lymphoid-rich tumor.

P40/p63 may support squamous differentiation in an appropriate immunophenotypic context.

Marker expression complements morphology; No single stain should be read in isolation.

Slide 35 · Pathology diagnosis: Integrated reasoning

Morphology on adequate biopsy

Confirm epithelial lineage

EBER status + histologic subtype

Report the contemporary NPC subtype and clinically useful ancillary findings.

Tissue diagnosis is required before disease-directed management.

Schematic — conceptual sequence, not a quantitative or clinical measurement

Slide 36 · Limited-biopsy pitfalls

Crush artifact can obscure vesicular chromatin, nucleoli, and tumor boundaries.

Reactive lymphoid tissue may dominate the sampled fragments.

Sparse carcinoma nests may require deeper levels or targeted immunostains.

Slide 37 · Differential: NPC versus lymphoma

Nasopharyngeal carcinoma

Atypical epithelial cells may be dispersed among lymphocytes.

Cytokeratin highlights the epithelial tumor population.

Tumor-cell EBER can support nonkeratinizing NPC.

Lymphoma

Neoplastic hematolymphoid cells comprise the primary tumor.

Hematolymphoid lineage markers are decisive.

EBV positivity alone never defines epithelial origin.

Slide 38 · Differential: NPC versus other poorly differentiated tumors

Nonkeratinizing NPC

Squamous epithelial phenotype may be subtle.

Commonly associated with epithelial-cell EBER positivity.

Consider anatomy and clinical findings together.

Other nasopharyngeal tumors

Neuroendocrine, lymphoid, or undifferentiated tumors can mimic morphology.

Use a targeted immunopanel rather than a single presumed marker.

NUT carcinoma is an important rare head-and-neck differential.

Slide 39 · Basaloid SCC: Classification is not a catch-all

Basaloid SCC is a separately recognized, uncommon NPC subtype.

A basaloid appearance does not by itself establish this specific diagnosis.

Differential diagnosis includes other small basaloid or poorly differentiated neoplasms.

Slide 40 · When the primary tumor is not obvious

Cervical nodal disease can be the presenting clinical problem.

Pathologic classification of a nodal metastasis should be integrated with nasopharyngeal examination.

Avoid assigning the primary site from one marker or histologic feature alone.

Slide 41 · Typical presenting symptoms

Nasal obstruction can result from a local nasopharyngeal mass.

Epistaxis reflects clinically evident bleeding from the upper aerodigestive site.

Cervical lymph-node metastases are commonly present at diagnosis.

Slide 42 · Nasal obstruction: The clinical clue

Persistent unilateral or unexplained obstruction warrants examination when other red flags coexist.

Symptoms can be confused with inflammatory or benign nasopharyngeal disorders.

Structural assessment and biopsy are essential when a suspicious lesion is identified.

Slide 43 · Epistaxis: Contextual interpretation

Epistaxis is one of the clinical manifestations explicitly.

It is a nonspecific symptom; Malignancy is considered in the context of a mass, nodal disease, or risk factors.

Associated obstruction or cervical adenopathy should increase diagnostic concern.

Slide 44 · Cervical nodal metastasis is a major presenting feature

Ipsilateral cervical lymph-node metastases in up to 70% of patients.

This is a quoted textbook figure, not an estimate for every population or clinical series.

The finding underscores the need to examine both the nasopharynx and cervical lymphatic chain.

Slide 45 · Nasopharynx to cervical nodal disease

Primary epithelial carcinoma

Regional lymphatic spread

Cervical metastatic lymph nodes

Retropharyngeal lymph nodes are a first-echelon drainage site in clinical staging descriptions.

A neck mass may draw attention before the nasopharyngeal lesion is recognized.

Schematic — conceptual sequence, not a quantitative or clinical measurement

Slide 46 · Why presentation may occur at advanced stage

Early nasal symptoms may be subtle or attributed to common benign causes.

The nasopharynx is not directly visible on routine external examination.

Locoregional extension and lymph-node spread can precede definitive diagnosis.

Slide 47 · Cranial-nerve and skull-base evaluation

Advanced local extension can involve skull-base and adjacent neural structures.

NCI staging guidance emphasizes careful cranial-nerve functional examination.

New focal neurologic symptoms require integration with endoscopic and imaging findings.

Slide 48 · Clinical diagnostic pathway

Risk features + symptoms + neck examination

Nasopharyngeal endoscopy / directed biopsy

Histologic classification + imaging stage

Confirm carcinoma on tissue rather than relying on EBV serology or imaging alone.

Plan regional and distant disease assessment after a tissue diagnosis.

Schematic — conceptual sequence, not a quantitative or clinical measurement

Slide 49 · Imaging: The questions MRI helps answer

MRI is especially useful for soft-tissue extent and the relationship to the skull base.

It can help evaluate intracranial extension more fully than CT alone.

Pathologic confirmation remains mandatory even when imaging strongly suggests NPC.

Slide 50 · PET/CT and staging context

PET/CT can contribute to nodal and distant metastatic evaluation.

It may also support radiation treatment planning.

Choice and sequencing of imaging depend on clinical stage and local guidance.

Slide 51 · Stage assessment: What T, N, and M represent

Component

Clinical question

Typical assessment

T — primary tumor

Where has the local tumor extended?

Endoscopy and cross-sectional imaging

N — regional nodes

Which regional nodal stations are involved?

Clinical exam and imaging

M — distant metastasis

Is disease present beyond locoregional sites?

Systemic staging imaging when indicated

Slide 52 · Staging is not the same as histologic subtype

Histologic subtype describes the tumor’s differentiation phenotype.

TNM stage describes anatomic disease extent.

Prognosis and treatment planning require both, together with the clinical context.

Slide 53 · Why radiotherapy is central to NPC management

Radiotherapy as a principal standard treatment.

Local anatomy and tumor radiosensitivity make nonsurgical management important.

Modern management is stage-dependent and may combine radiation with systemic therapy.

Slide 54 · Radiation response differs by histologic subtype

Nonkeratinizing NPC

Undifferentiated morphology is associated with greater radiosensitivity.

A strong EBV association characterizes most of this category.

Keratinizing NPC

Keratinizing tumors are relatively less radiosensitive.

Substantially less favorable historical survival.

Slide 55 · Textbook survival statistics: Interpret in context

Approximately 60% overall 5-year survival in the passage.

It gives stage-dependent 5-year survival of 70%–98% for nonkeratinizing tumors and about 20% for the keratinizing form.

These are textbook-reported historical figures, not individualized predictions or a replacement for contemporary stage-specific estimates.

Slide 56 · Advanced and recurrent disease: Treatment context

Disease that is metastatic or no longer amenable to local therapy may require systemic treatment.

NCI and updated clinical guidance describe multimodality management depending on stage and fitness.

The pathology lecture emphasis is how subtype, extent, and clinical setting inform the treatment pathway.

Slide 57 · Checkpoint inhibitors in advanced NPC

Checkpoint-inhibitor use for selected advanced or recurrent cancers.

Clinical decisions depend on disease setting and contemporary treatment guidelines.

Do not infer benefit for every histologic subtype or patient from the fact that an agent is available.

Slide 58 · Diagnostic versus prognostic biomarkers

Marker / variable

Role in NPC

Important limitation

Tumor-cell EBER

Supports EBV-associated NPC diagnosis

Interpret only in malignant epithelial cells

Circulating EBV DNA

Clinical biomarker for disease burden / prognosis

Does not replace biopsy or anatomical staging

Histologic subtype

Morphologic classification; Response association

Stage and treatment modify outcomes

Anatomic stage

Extent-based prognostic framework

Not interchangeable with differentiation

Slide 59 · Case 1: Nasal symptoms with cervical adenopathy

A patient from a high-incidence region has persistent nasal obstruction, intermittent epistaxis, and an enlarged upper cervical lymph node. Endoscopy identifies a suspicious nasopharyngeal lesion.

Which specimen establishes the primary diagnosis?

Which histologic and viral features would favor nonkeratinizing NPC?

Slide 60 · Case 1: Diagnostic reasoning

Targeted nasopharyngeal biopsy

Find malignant epithelial cells in lymphoid stroma

Confirm cytokeratin + tumor-cell EBER

Regional imaging helps characterize locoregional spread after pathologic confirmation.

Risk-region background supports suspicion, but does not itself diagnose carcinoma.

Schematic — conceptual sequence, not a quantitative or clinical measurement

Slide 61 · Case 2: A lymphocyte-rich small biopsy

An endoscopic biopsy contains numerous small lymphocytes and scattered large atypical cells with vesicular nuclei, conspicuous nucleoli, and indistinct membranes.

What critical lineage question must be answered?

How would cytokeratins and EBER be interpreted together?

Slide 62 · Case 2: Resolving the lineage problem

Morphologic reasoning

Large atypical cells stand out from small reactive lymphocytes.

Indistinct borders suggest a syncytial epithelial tumor phenotype.

Ancillary-test reasoning

Cytokeratin staining supports the epithelial malignant-cell population.

EBER nuclear labeling in those cells supports EBV-associated NPC.

Slide 63 · Diagnostic synthesis: Characteristic patterns

Feature

Nonkeratinizing NPC

Keratinizing NPC

Squamous maturation

Often subtle

Conspicuous / keratinizing

Tumor cell borders

Frequently indistinct

Often more apparent

Lymphoid background

Commonly prominent

Variable

EBV association

Strong in most cases

Less consistent

Radiosensitivity

Greater

Lower

Slide 64 · Five high-yield recognition points

Think of NPC when nasal symptoms coexist with unexplained cervical lymphadenopathy.

Classify the tumor as keratinizing, nonkeratinizing, or basaloid SCC.

Nonkeratinizing NPC often has syncytial tumor cells in a dense T-cell-rich background.

EBER must be localized to malignant epithelial cells, not simply present in the biopsy.

Interpret treatment response and survival using both histology and stage.

Slide 65 · Selected references and source scope

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026; Ch. 16, pp. 674–675.

WHO Classification of Tumours Editorial Board. Head and Neck Tumours. 5th ed. IARC; 2024 (NPC, pp. 117–126).

Badoual C, et al. Update from the WHO 5th edition: Oropharynx and Nasopharynx. Head Neck Pathol. 2022.

National Cancer Institute. Nasopharyngeal Carcinoma Treatment (PDQ), Health Professional Version.

SEOM–TTCC clinical guideline for nasopharyngeal carcinoma (2025 update).

Primary textbook claims and newer clinical/classification material are distinguished in slide speaker notes.