Signs of cancerous sinusitis may include bleeding, the presence of foul-smelling pus, and recurrent sinusitis. Patients with sinusitis usually have symptoms such as nasal congestion, large amount of purulent or mucopurulent nasal mucus, headache, and loss of sense of smell. Most patients can be cured after active and standardized treatment, and will not cause cancer. When patients with sinusitis suddenly have frequent nasal bleeding, or foul-smelling purulent nasal discharge, or nasal congestion worsens significantly, or repeated episodes of sinusitis can not be cured and other symptoms, then it may be a sign of cancerous development of sinusitis. However, a single symptom is not a basis for diagnosis, and it is necessary to carry out other auxiliary examinations and combine with other signs and symptoms of the patient to determine. It is recommended that patients with sinusitis should be treated under the guidance of a doctor to avoid further aggravation and deterioration of the condition.