Owing to unique anatomical structure of the nose and paranasal sinuses surrounded by hard bones, subjective symptoms do not develop until a tumor grows extensively outside the cavity. When a tumor mass progresses to the superior, inferior or anterior region, patients visit a hospital relatively in early stage because of the symptoms of exophthalmus, palate swelling or cheek swelling, respectively. However, when a mass progresses in the posterior or lateral region, these cases are rather in advanced stage because of the late symptoms of trismus or trigeminal neuralgia. For the purpose of improving prognosis of these advanced cases, we have been treating patients actively by surgery. Neurosurgical knowledge is needed when a dissection is to be performed at the basal region of the skull in advanced cancer of the nose and paranasal sinuses. The detail of operations and prognosis of 13 cases treated with extended maxillectomy in Shikoku National Cancer Center Hospital were reported and discussed.