This contains a heterogenous group of rare malignancies. The most common type is squamous cell carcinoma followed by salivary gland tumours. A number of uncommon tumours also occur, in higher proportion than in other head and neck sites.
The location of the primary tumour varies considerably by sub-site:
- Maxillary Sinus - 60%
- Nasal Cavity - 25%
- Ethmoid Sinuses - 14%
- Frontal/Sphenoid Sinus - 1%
Sinonasal tumours represent about 3% of mucosal head and neck tumours, making this location one of the less common sites. The most common type is squamous cell carcinoma.
Woodworking has been associated with sinonasal adenocarcinoma. Smoking increases the risk of squamous cell carcinoma but not to the same degree as in other sites.
Tumours are often locally aggressive regardless of type. They can invade into adjacent sinuses, into the orbit (causing blindness and proptosis), into the oral cavity, superiorly into the brain or posteriorly into the cavernous sinus. Some tumours (eg. adenoid cystic carcinoma) favour perineural invasion and may spread into the pterygopalatine fossa and intracranially along branches of the maxillary nerve.
Patients typically present with chronic sinus symptoms and nasal obstruction. Due to the frequency of these symptoms with benign causes, time until diagnosis is made is frequently delayed and many tumours are locally advanced at presentation.
CT, MRI and PET are all useful modalities. The important aspects on imaging are to determine:
- Involvement of the orbit
- Involvement of the skull base, meninges or brain
- Involvement of the cavernous sinus
- The relationship of the tumour to the internal carotid artery
Tumours that invade any of these structures present significant barriers to surgical resection.
Tumour features are individual to the various types that may occur in the sinonasal region.
- Benign Sinonasal Tumours
- Olfactory Neuroblastoma
- Sinonasal Adenocarcinoma
- Sinonasal Melanoma
- Sinonasal Neuroendocrine Tumours
- Sinonasal Sarcoma
- Sinonasal Squamous Cell Carcinoma
- Sinonasal Undifferentiated Carcinoma (SNUC)