Preoperative Imaging and Surgical Findings in Pediatric Frontonasal Dermoids

Abstract

ObjectiveTo review cases of congenital frontonasal dermoids to gain insight into the accuracy of preoperative computed tomography (CT) and magnetic resonance imaging (MRI) in predicting intracranial extension.MethodsThis retrospective study included all patients who underwent primary excision of frontonasal dermoids at an academic children's hospital over a 23‐year period. Preoperative presentation, imaging, and operative findings were reviewed. Receiver operating characteristic (ROC) statistics were generated to determine CT and MRI accuracy in detecting intracranial extension.ResultsSearch queries yielded 129 patients who underwent surgical removal of frontonasal dermoids over the study period with an average age of presentation of 12 months. Preoperative imaging was performed on 122 patients, with 19 patients receiving both CT and MRI. CT and MRI were concordant in the prediction of intracranial extension in 18 out of 19 patients. Intraoperatively, intracranial extension requiring craniotomy was seen in 11 patients (8.5%). CT was 87.5% sensitive and 97.4% specific for predicting intracranial extension with an ROC of 0.925 (95% CI [0.801, 1]), whereas MRI was 60.0% sensitive and 97.8% specific with an ROC of 0.789 (95% CI [0.627, 0.950]).ConclusionThis is the largest case series in the literature describing a single institution's experience with frontonasal dermoids. Intracranial extension is rare and few patients required craniotomy in our series. CT and MRI have comparable accuracy at detecting intracranial extension. Single‐modality imaging is recommended preoperatively in the absence of other clinical indications.Level of EvidenceIV Laryngoscope, 2023

Special Considerations in Pediatric Endoscopic Skull Base Surgery

“…Naturally, it is important to determine the degree of dural extension before any type of surgical intervention, which can be seen in 5-45% of lesions [16,21,22]. CT or MRI is recommended to evaluate for intracranial dermoid cyst extension, but there is a debate over which modality, not if both, should be obtained preoperatively [23]. CT may be fast and highlight osseous structures, but there is significant concern for radiation exposure, especially for young children.…”

“…CT may be fast and highlight osseous structures, but there is significant concern for radiation exposure, especially for young children. MRIs negate this concern, but often require sedation and long acquisition times [23]. According to a recent single-institution study comparing the accuracy of CT and MRI in predicting intracranial extension for frontonasal dermoids, the authors demonstrated that the sensitivity and specificity of CT were 87.5% and 97.4%, respectively, whereas MRI was 60.0% and 97.8%, respectively.…”

“…The authors concluded that a single modality should be chosen given comparable accuracy. MRI was generally preferred in their analysis [23]. In the setting of nasal dermoid cysts, CT may demonstrate bifid crista galli, which may be suggestive of a skull base defect [24].…”