Tumors of the paranasal sinuses.

Benign and malignant tumors, including polyps, represent conditions that occur frequently enough to be considered in the differential diagnosis of sinus disease. The locations and extent of these lesions (especially malignant tumors) should be evaluated by CT and MRI. This is especially indicated when malignant lesions extend outside the confines of the paranasal sinuses into adjacent areas, such as the orbit, intracranial cavity, and parapharnygeal space.