General Medical Information

Neoplastic Disease

Barbara A. Zeifer

Tumors of the nose and paranasal sinuses are encountered far less often than inflammatory disease and polyposis. Malignant disease of the nose and paranasal sinuses accounts for less than 1% of all malignant lesions in the body and 3% of all head and neck tumors. Cross-sectional imaging plays an integral role in the diagnostic evaluation of these lesions. Computed tomography and MRI offer a range of information about density, signal intensity, contrast enhancement, and mass effect that helps to differentiate benign from malignant disease and tumor from secondary mucosal inflammation. Magnetic resonance imaging is particularly useful, because nearly 95% of all sinonasal tumors are low to intermediate in signal intensity during the T2-weighted sequence. This allows differentiation from the high signal intensity of polyps, mucosal inflammation, and retained secretions.

Findings at contrast-enhanced CT can suggest the diagnosis of neoplasm but do not approach the specificity of MRI findings. The exception is in the evaluation of bone lesions, in which CT shows the calcific and ossific components to better advantage. Both CT and MRI give precise anatomic detail regarding tumor location, extension, and origin that is critical in the determination of operability or in planning radiation therapy. Magnetic resonance imaging has an advantage over CT because optimal imaging planes can be selected to maximize the information obtained. Tumor extension into adjacent sinuses or into the orbit, pterygopalatine fossa, infratemporal fossa, and the cranium must be clearly defined.

The pattern of bony involvement is an important diagnostic point in the evaluation of sinonasal tumors. Slow tumor growth causes gradual expansion of the sinus cavity and allows progressive remodeling of bone. Aggressive lesions cause focal and irregular destruction of bone. Squamous cell carcinoma almost never behaves as a slowly expansile lesion associated with bone remodeling. Other malignant tumors, including adenoid cystic carcinoma and melanoma, can do so. Thickening and sclerosis of a sinus wall are unlikely to be caused by malignant disease unless preceded by chronic inflammation.