The evaluation triad of patients with nasal and anterior skull base tumors is the history, the head and neck examination and imaging. The physical examination of the head and neck should include testing all the cranial nerves. These nerves mediate such important functions as vision, smell, swallowing, speech, hearing and balance, and facial movement and sensation. Nasal endoscopy or visualization of the nasal cavities of an optical telescope is another important evaluation tool.
As is shown in the intraoperative endoscopic photograph of the right nose (nasal septum NS) , tumors (tumor [T], neurosurgical cottonoid or sponge [C]) frequently have irregular surfaces, are friable and easily hemorrhage. The third element of the evaluation triad is imaging. Imaging consists of computer tomography (CT) to best visualize the nasal and sinus cavities, and bone and tissues of various densities. However, a sinus filled with either tumor or mucus will appear similar on CT scanning. Magnetic resonance imaging (MRI) complements CT by better delineating soft tissue from bone, and better visualizing soft tissue and fluid.
The image of the same patient as seen above illustrates the value of MRI (insert figure- inverting papilloma preop coronal MRI). The patient's left maxillary sinus (L-max) is filled with fluid which is unrelated to the tumor (T) in the right maxillary sinus and nose. On CT scanning the tumor and the fluid within the left maxillary sinus would be indistinguishable from each other, whereas MRI clearly shows two distinct processes. However, MRI does not show the presence or absence of bone as the tumor can spread beyond the nose and sinuses. CT provides this information and together both forms of imaging aid the surgeon in planning treatment.
More recently, positron emission tomography (PET) is used to both evaluate the presence of viable tumor and to search for spread of tumor to regional or distant site. Unlike CT or MRI, PET images the metabolic activity of tissues and organs. When PET is combined with CT both structure and metabolic activity are visualized. In the preoperative evaluation of patients who have malignant tumors PET/CT is particularly useful to look for distant disease which would likely preclude surgical removal of the tumor and most likely the patient would be treated with radiation and chemotherapy. For example, the PET/CT of a patient post radiation therapy and maxillectomy for a malignant neoplasm shows tumor (T) within the right ethmoid sinus, orbit and skull base (insert figure- PET scan of C4 metastasis). This patient was being consider for resection of their tumor until the PET scan showed metastasis to the fourth cervical vertebra (C4). In the post-treatment patient PET can help to distinguish to distinguish between recurrent tumor and post-treatment changes on imaging.