Magnetic resonance imaging of congenital midline nasal masses.

Congenital midline nasal masses are rare lesions with potential intracranial extensions. Thus, thoughtful preoperative evaluation is essential in planning the appropriate surgical approach, to prevent such complications as cerebral spinal fluid leaks and meningitis. Preoperative computerized tomographic (CT) scans are useful in visualizing bony defects, but are not well suited for soft tissue imaging. Magnetic resonance imaging (MRI) is the latest advance in cross-sectional imaging technology. It offers superior soft tissue contrast, is noninvasive, and does not use ionizing radiation. It is particularly useful in imaging encephaloceles. Three cases of congenital midline masses are presented as illustrations. Two dermoid cysts demonstrate the usefulness of MRI in ruling out intracranial extension. A large encephalocele dramatically demonstrates the superiority of MRI in imaging the brain herniating into the nose. Since MRI is noninvasive and does not use ionizing radiation, it should be considered before CT scanning, to rule out intracranial extension.