Benign lesions
Squamous cell papillomas
- Most common
Sinonasal papillomas
Aetiology
- HPV (low risk), organic solvents
- Patients tend to be 50+ and more common in males
Histology
- Inverted, exophytic or oncocytic
- Inverted and oncocytic on lateral walls and paranasal sinuses, exophytic on nasal septum
- Epithelium can be respiratory, squamous, or oncocytic with mucocytes and neutrophilic infiltrate
- Rarely undergo malignant change

Recurrent respiratory papillomatosis
- Rare condition in which papilloma form along the aerodigestive tract
- Associated with HPV
- Can often present in children with hoarse voice and progressive SOB
Others
- Angiofibromas
Malignant lesions
Squamous cell carcinoma
- Most common
Nasopharyngeal carcinoma
Aetiology
- Low incidence in UK, very high in far east
- Higher incidence in males
- Strong association with EBV, as well as volatile nitrosamines in food
- Other risk factors - occupation, family history, smoking, alcohol, HPV
Histology
- Keratinising SCC, non-keratinising SCC, baseloid SCC
- Highly malignant - extensive local spread, early nodal metastasis
Others
- Primary adenocarcinoma
- Neuroblastoma
- Lymphoma
Epstein-Barr virus in carcinogenesis
- Seen in association with Burkitt's lymphoma, other B-cell lymphomas and Hodgkin's lymphoma
- Infects epithelial cells of oropharynx and B-cells
- Ubiquitous infection, mostly subclinical
- EBV genes 'hi-jack' normal signalling pathways
- LMP-1 acts as an oncogene
- EBNA-2 promotes transition from G0 to G1