Developmental nasal midline masses in children: neuroradiological evaluation.

Developmental nasal midline masses in children are rare lesions. Neuroimaging is essential to characterise these lesions, to determine the exact location of the lesion and most importantly to exclude a possible intracranial extension or connection. Our objective was to evaluate CT and MRI in the diagnosis of developmental nasal midline masses. Eleven patients (mean age 4.5 years) with nasal midline masses were examined by CT and MRI. Neuroimaging was evaluated for (a) lesion location/size, (b) indirect (bifid or deformed crista galli, widened foramen caecum, defect of the cribriform plate) and direct (identification of intracranially located lesion components or signal alterations) imaging signs of intracranial extension, (c) secondary complications and (d) associated malformations. Surgical and histological findings served as gold standard. Nasal dermoid sinus cysts were diagnosed in 9 patients. One patient was diagnosed with an meningocele and another patient with a nasal glioma. Indirect CT and MRI signs correlated with the surgical results in 10 of 11 patients. Direct CT findings correlated with surgery in all patients, whereas the direct MRI signs correlated in 9 of 11 patients. In 2 patients MRI showed an intracranial signal alteration not seen on CT. Neuroimaging corrected the clinical diagnosis in 1 patient. One child presented with a meningitis. In none of the patients was an associated malformation diagnosed. Intracranial extension is equally well detected by CT and MRI using indirect imaging signs. Evaluating the direct imaging signs, MRI suspected intracranial components in 2 patients without a correlate on CT. This could represent an isolated intracranial component that got undetected on CT and surgery. In 9 patients CT and MRI matched the surgical findings. The MRI did not show any false-negative results. These results in combination with the multiplanar MRI capabilities, the different image contrasts that can be generated by MRI and the lack of radiation favour the use of MRI as primary imaging tool in these young patients in which the region of imaging is usually centred on the radiosensitive eye lenses.