user: What is (are) Paranasal Sinus and Nasal Cavity Cancer ?

assistant: Key Points
                    - Paranasal sinus and nasal cavity cancer is a disease in which malignant (cancer) cells form in the tissues of the paranasal sinuses and nasal cavity.    - Different types of cells in the paranasal sinus and nasal cavity may become malignant.    - Being exposed to certain chemicals or dust in the workplace can increase the risk of paranasal sinus and nasal cavity cancer.     - Signs of paranasal sinus and nasal cavity cancer include sinus problems and nosebleeds.    - Tests that examine the sinuses and nasal cavity are used to detect (find) and diagnose paranasal sinus and nasal cavity cancer.    - Certain factors affect prognosis (chance of recovery) and treatment options.
                
                
                    Paranasal sinus and nasal cavity cancer is a disease in which malignant (cancer) cells form in the tissues of the paranasal sinuses and nasal cavity.
                    Paranasal sinuses    "Paranasal" means near the nose. The paranasal sinuses are hollow, air-filled spaces in the bones around the nose. The sinuses are lined with cells that make mucus, which keeps the inside of the nose from drying out during breathing.     There are several paranasal sinuses named after the bones that surround them:         - The frontal sinuses are in the lower forehead above the nose.    - The maxillary sinuses are in the cheekbones on either side of the nose.    - The ethmoid sinuses are beside the upper nose, between the eyes.    - The sphenoid sinuses are behind the nose, in the center of the skull.         Nasal cavity    The nose opens into the nasal cavity, which is divided into two nasal passages. Air moves through these passages during breathing. The nasal cavity lies above the bone that forms the roof of the mouth and curves down at the back to join the throat. The area just inside the nostrils is called the nasal vestibule. A small area of special cells in the roof of each nasal passage sends signals to the brain to give the sense of smell.   Together the paranasal sinuses and the nasal cavity filter and warm the air, and make it moist before it goes into the lungs. The movement of air through the sinuses and other parts of the respiratory system help make sounds for talking.     Paranasal sinus and nasal cavity cancer is a type of head and neck cancer.
                
                
                    Different types of cells in the paranasal sinus and nasal cavity may become malignant.
                    The most common type of paranasal sinus and nasal cavity cancer is squamous cell carcinoma. This type of cancer forms in the squamous cells (thin, flat cells) lining the inside of the paranasal sinuses and the nasal cavity.    Other types of paranasal sinus and nasal cavity cancer include the following:         -  Melanoma: Cancer that starts in cells called melanocytes, the cells that give skin its natural color.    -  Sarcoma: Cancer that starts in muscle or connective tissue.    -  Inverting papilloma: Benign tumors that form inside the nose. A small number of these change into cancer.    - Midline granulomas: Cancer of tissues in the middle part of the face.