Sinusitis bleeding, if the frequency and amount of bleeding are not much, may be caused by sinusitis bleeding without cancer, if the nasal cavity bleeds repeatedly, then it may be caused by sinusitis cancer. Sinusitis is an inflammatory disease of the mucous membrane of the sinuses, which may also cause bleeding when it is serious, but the frequency and amount of bleeding caused by sinusitis are relatively small. If there is repeated bleeding on one or both sides of the nose, or there is a small amount of blood within the nasal cavity, especially if there is some special smell in the nose, then the bleeding is considered to be caused by sinusitis cancer. Sinusitis that causes cancer is usually chronic sinusitis, which is because long-term chronic inflammatory stimulation can cause large squamous metaplasia of the mucosal epithelium of the sinuses, forming the basis for the occurrence of squamous cell carcinoma. Sinus cancer is difficult to be detected in the early stage of sinus cancer because of the hidden anatomical location and few early symptoms. If there are symptoms of bleeding, anterior and posterior rhinoscopy and nasal endoscopy can be done to clarify whether it is sinus cancer. Of course, the diagnosis should be confirmed by pathological examination of tumor tissue and sinus puncture cell smear in the end, and after the diagnosis is confirmed, the size and invasion range of tumor can be clarified by sinus CT or MRI examination so as to choose the suitable treatment plan for you. Sinusitis bleeding may be caused by cancer, so we must pay attention to it and go to the hospital for relevant examination as soon as possible, and follow the medical advice for treatment after diagnosis.