The most common sinonasal tumour, SCC is treated in a similar way to SCC in other sites, albeit altered by the different anatomical structures.
Epidemiology
SCC of the sinonasal region occurs most commonly in men, with a mean age of 60 at diagnosis. Sinonasal SCC is one of the rarest locations for SCC in the head and neck region.
Aetiology and Pathogenesis
Smoking is a known risk factor, as is infection with HPV.
Natural History
Some SCCs arise in a benign tumour - sinonasal inverted papilloma - that is unique to the region. About 10% of papillomas have an associated squamous cell carcinoma.
Local invasion is common. Lymph node involvement becomes more likely with T3 and T4 tumours, requiring management of the neck. Sinonasal tumours typically spread to levels IB and II, although posterior lesions that involve the nasopharynx may also spread to levels III and V.
Tumour/Normal Tissue Features
Macroscopic
Multiple appearances are described. Areas of necrosis and haemorrhage are possible. The tumour can be invasive, polypoid, or both.
Microscopic
Keratinizing squamous cell carcinoma is the most common variant; other variants (eg. basaloid, papillary) can occur but are less frequent than other sites.
A special type of SCC in the sinonasal tract is the non-keratinising squamous cell carcinoma. This can grow in papillary or ribbon like fashion through tissues and the border is often well demarcated.
Immunohistochemistry
No special stains are used.
