CT appearance distinguishing benign nasal polyps from malignancies.

In many cases the common nasal polyp is confused clinically, radiographically, and, on occasion, pathologically with a tumor of the nasal vault and paranasal sinuses. Similarly, this distinction often cannot be made by CT. However, we have identified in 12 patients a CT appearance of looping, minimally or nonenhancing soft tissue densities within a mucoid density background matrix, that is associated with cases of polyposis (nine patients) and fungal disease (three patients). We believe that when this CT appearance is present, malignant disease can be essentially eliminated from the differential diagnosis.