Congenital nasal masses: CT and MR imaging features in 16 cases.

The imaging studies of 16 children with pathologically proved nasal encephaloceles (eight), nasal dermal sinuses/nasal dermoids (seven), and nasal cerebral heterotopias, more commonly known as nasal gliomas (one), were retrospectively reviewed and compared with normal control subjects to define the normal anatomy and analyze deformities caused by these lesions. Nasal encephaloceles were always identified as complex masses of mixed soft tissue and CSF intensity that were contiguous with intracranial structures. The nasal glioma appeared as a mixed-intensity mass that, on the basis of the CT scan, appeared to be continuous with intracranial structures. Nasal dermal sinuses could only be identified as they coursed through the skin and subcutaneous soft tissue. They could not be identified when intraosseous. Moreover, on CT and, particularly, on MR, a number of potential diagnostic pitfalls were encountered. The most important of these was the normal fat deposition that occurs within bone during normal maturation and during aeration of the frontal sinuses and nasal bones. These fatty changes can easily be mistaken for fatty tumors if they are not recognized as normal anatomic changes. Interestingly, the classic plain film findings for congenital nasal masses were present only in the encephaloceles and nasal glioma; dermoids and dermal sinuses showed none of the classic plain film findings. In the six patients who had both CT and MR, the masses were easily identified and characterized by each imaging method. Congenital nasal masses are well characterized by both CT and MR. It is important to understand the normal changes in the anatomy of the nasofrontal region in the pediatric age group to avoid false-positive diagnoses in this region.