A semicircular elevation of the hard palate is a symptom that occurs when the production and growth of malignant tumors of the maxillary sinus affect the structure and function of the surrounding tissues. Maxillary sinus malignancies account for 40.3% of nasal malignancies and 1.2% of systemic malignancies. How to diagnose a semicircular elevation of the hard palate? Maxillary sinus malignant tumor can be asymptomatic in the early stage because of its large cavity and different primary sites, so it is mostly found in the examination. When the tumor grows gradually and affects the structure and function of surrounding tissues, it can produce corresponding symptoms and signs. If the tumor develops to the nasal cavity, there will be nasal congestion, mucous-purulent nasal discharge with blood and foul smell. On examination of the nasal cavity, the lateral wall of the nasal cavity is seen to move inward to narrow the nasal cavity. Sometimes there is a mass in the middle nasal passage or nasal cavity, which is a favorable time for biopsy to clarify the pathological diagnosis. If the tumor invades the nasolacrimal duct, tear overflow may appear. If the anterior wall of maxillary sinus is involved, there is cheek swelling, deformity and facial numbness and pain. If the tumor infiltrates to the bottom, patients often have toothache, swollen gums, loose teeth and semicircular elevation of hard palate, which are easily misdiagnosed as dental disease and their symptoms are aggravated after tooth extraction. The tumor can also develop to the posterior wall of maxillary sinus and invade the pterygopalatine fossa, causing difficulty in opening mouth. If the tumor destroys the infraorbital wall or enters the orbit, eye displacement and visual impairment may occur. In advanced stage, the tumor may invade the anterior cranial sinus through the sieve sinus and orbit, and may go through the pterygomaxillary fossa, pterygopalatine fossa, and then destroy the roof of pterygopalatine fossa, or involve the inferior temporal fossa and enter the middle cranial fossa. Any clinical symptoms such as mass in the inner canthus, difficulty in opening mouth, neck bulge, intractable headache and ear pain suggest the possibility of skull base or intracranial metastasis. For malignant tumor of maxillary sinus, about 1/2 of them have lymph node metastasis. caused by malignant tumor of maxillary sinus. In the early stage, the tumor is small and confined to a certain part of the sinus cavity with no obvious symptoms. With the development of tumor, the following symptoms will appear successively: unilateral pus and blood nasal discharge; pain or numbness in the cheek (pain or numbness in the affected cheek due to tumor invasion of infraorbital nerve. It may be the first symptom and is very important for early diagnosis); unilateral progressive nasal congestion (caused by the invasion of the lateral wall of the nasal cavity by tumor extrusion); unilateral maxillary sinus molar pain or loosening (caused by tumor invading downward to the alveolar cavity). In advanced stage, malignant tumor of maxillary sinus destroys sinus wall and expands to adjacent tissues, which may cause the following symptoms: (1) Cheek bulge: tumor compression destroys anterior wall, which may cause cheek bulge and invade soft tissue and skin of cheek, and fistula or ulceration may occur. (2) Ocular symptoms: Tumor compression of nasolacrimal duct may cause tearing; upward compression of orbital floor may cause upward displacement of eyeball. (3)Hard palate bulge: downward expansion of tumor may cause semicircular bulge of hard palate and labial gingival sulcus, or even ulceration, thickening of dental grooves, pressing loosening or falling off. (4) Difficulty in opening mouth: When the tumor invades outward into the pterygoid fossa and internal pterygoid muscle, it may cause intractable neuralgia and difficulty in opening mouth. (5) Skull base involvement: It may appear as a mass in the internal bladder, or have difficulty in opening mouth, temporal bulge, headache, ear pain and other symptoms. (6) Cervical lymph node metastasis: occurs in the later stages.