What Is Cancer of the Nasal Cavity & Paranasal Sinuses?

The nasal cavity consists of the passageways behind the nose that air moves through when breathing. The nasal cavity starts behind the nose, passes over the roof of the mouth, and connects to the throat (nasopharynx). There is a left and right nasal cavity, separated by the nasal septum. Tumors may form anywhere in the nasal cavity, including the septum, the inner nostril, the floor of the nasal cavity, or the side wall of the nasal cavity.

The paranasal sinuses are hollow cavities in the bones around the nasal cavity. The insides of the sinuses are lined with a membrane that produces mucus in order to keep the nasal cavity moist. Other functions of the sinuses include lightening the weight of the skull and giving your voice resonance (a deep, full, amplifying sound).

Tumors may form in any of the following parts of the sinuses:

• Maxillary sinuses: A pair of maxillary sinuses are located in the cheekbones on either side of the nose, between the top teeth and the eye. The maxillary sinuses are the largest sinus cavities and the most common site of sinus cancer.

• Ethmoid sinuses: A pair of ethmoid sinuses are located between the eyes, on either side of the top of the nose.

• Sphenoid sinuses: A pair of sphenoid sinuses are located deeper inside the center of the skull, directly behind the nose at the skull base.

• Frontal sinuses: A pair of frontal sinuses are located in the lower forehead, above the eyes and nose.

The most common type of cancer in the nasal cavity and paranasal sinuses is squamous cell carcinoma, which starts in the thin, flat cells that line the inside of these regions. Sinonasal tumors in general are rare, but of the ones that do occur, most develop within the maxillary sinuses or nasal cavity. Tumors in the ethmoid sinuses are even more rare and tumors in the frontal and sphenoid sinuses are extremely rare.