The maxillary sinuses, along with the septal, frontal, and pterygoid sinuses, are the cavities of the skull near the nasal cavity. The maxillary sinuses, one on each side, are located between the base of the orbit, the lateral side of the nasal cavity, and above the hard palate of the oral cavity, and it opens in the middle nasal canal of the nasal cavity. The maxillary sinuses are part of the paranasal sinuses and, like the other paranasal sinuses, have a role in enhancing the sense of smell in lower animals. In humans, it enhances the resonance of sound and can assist the nasal mucosa to moisten the air inhaled into the nasal cavity. The maxillary sinus allows the weight of the skull to be reduced, making it easier to maintain a balanced position. The maxillary sinus also serves to cushion external forces when the head is traumatized and can protect the head and orbital tissues. However, malignant tumors sometimes appear in this important cavity of the body – carcinoma of the maxillary sinus, which is one of the common malignant tumors in oral and maxillofacial surgery, with squamous cell being the most common, followed by basal cell carcinoma, adenoid cystic carcinoma, adenocarcinoma, etc., and sarcoma being less common. Because of its location in maxillary sinus, it is asymptomatic in early stage and not easy to be detected. It is only when the tumor develops to a certain extent and shows more obvious symptoms that it is noticed. Clinical manifestations In the early stage, because the cancer is confined to the maxillary sinus, the patient is not detected because there are no symptoms. When the tumor develops to a certain extent, obvious symptoms will appear. Clinically, different symptoms may appear according to different primary sites of the tumor: 1. When the tumor occurs in the inner wall of maxillary sinus, nasal obstruction, epistaxis, increased secretion from the lateral nasal cavity, nasolacrimal duct obstruction and lacrimation may occur. 2. When it occurs in the upper wall of maxillary sinus, there is protrusion and upward displacement of the eyeball, which may cause diplopia and lacrimation. 3.If it occurs in the anterior wall of maxillary sinus, it shows swelling of the face and buccal sulcus, later the skin breaks down and the tumor is exposed, and the involvement of infraorbital nerve may cause dull sensation or numbness in the cheek. 4.When it occurs in the posterior wall, there is difficulty in opening mouth. 5.When it occurs in the lower wall, there will be loose teeth, pain, swelling in the buccal sulcus, or the wound will not heal after tooth loss, and the swelling will protrude. 6. There may be submandibular and cervical lymph node metastasis, and sometimes metastasis to preauricular and retropharyngeal lymph nodes. Diagnosis and differentiation All the above clinical manifestations should be considered as the possibility of maxillary sinus cancer; X-ray sinus radiography can understand the scope of cancer invasion and bone destruction; in addition, CT examination can further understand the scope of lesion and determine the scope of radiotherapy and surgery; maxillary sinus biopsy can confirm the diagnosis. Maxillary sinus cancer should be differentiated from maxillary sinus cyst, odontogenic maxillary sinusitis, intra-nasal polyp, trigeminal neuralgia, etc. Treatment Patients are seen in oral and maxillofacial surgery or otorhinolaryngology depending on the clinical presentation. Both departments can treat maxillary sinus cancer, but oral and maxillofacial surgery should be the better treatment in this area because it is more familiar with the anatomy of the face (including maxillary sinus and surrounding tissues and organs), and it is mostly involved in repairing maxillary defects in the oral cavity after surgery. The treatment of maxillary sinus cancer should be a comprehensive treatment mainly based on surgery, especially combined with radiotherapy. 1.Radiotherapy: Cases diagnosed as maxillary sinus cancer can be treated with preoperative radiotherapy first, and surgery after 2–4 weeks of radiotherapy. This method has been accepted by most doctors, and practice shows that preoperative radiotherapy is significantly better than postoperative radiotherapy. 2.Surgery: It is the main treatment method for maxillary sinus cancer. The scope of surgery should be decided according to the lesion scope before radiotherapy, rather than the lesion scope after radiotherapy. In principle, total maxillary resection should be performed. If the lesion reaches the infraorbital plate, total maxillary resection including orbital contents should be performed; if the lesion involves other parts, extended radical maxillary resection or even combined craniomaxillary resection should be performed. If there are lymph node metastases in the neck, cervical lymph node dissection should be performed. After surgery, prosthetic treatment (similar to movable dentures) can be performed in the stomatology department to restore the facial shape and solve the problems of eating and pronunciation. 3.Chemotherapy The main treatment is pindamycin or fluorouracil chemotherapy. Immunotherapy and traditional Chinese medicine can also be added. Early prevention and treatment Early treatment of maxillary sinus cancer is the key to achieve good therapeutic effect. However, since there is obvious bone destruction only at a later stage, it is sometimes difficult to diagnose based on clinical manifestations alone, so once the patient has symptoms of maxillary sinus lesion, various means of examination should be actively used to make a clear diagnosis as early as possible, and maxillary sinus exploration is feasible if necessary. Surgery, so that early detection, timely treatment.