Cranial Erosion Associated With Non-Midline Dermoid Cysts in the Pediatric Population

Background:While the risk for intracranial extension of midline nasoglabellar dermoid cysts is well-described, the risk in non-midline dermoid cysts and role of preoperative imaging in these lesions is less understood. This study aims to address this gap and provide preoperative recommendations.Materials and Methods:A retrospective review was performed evaluating patients who underwent excision of craniofacial dermoid cysts by a single surgeon. Findings on preoperative physical examination and imaging modalities were compared to intraoperative findings to assess effectiveness of each in predicting bony erosion. A treatment algorithm is proposed.Results:Twenty-eight patients were included and 50% had intraoperatively confirmed bony erosion. Bony erosion was identified in 100% of lesions immobile on examination, compared to 30% of mobile lesions (P=0.001). Bony erosion was identified in 40.9% of lateral brow cysts compared to 83.3% of lesions located elsewhere (P=0.03), in 60% of patients with periorbital sequelae compared to 47.8% without periorbital sequelae, and in 66.7% of patients with reported change in cyst size with Valsalva compared to 48.0% without change with Valsalva. Sensitivities for preoperative identification of bony erosion were as follows: Physical examination 57.1%, US 11.1%, MRI 66.7%, and CT 100%.Conclusions:A management algorithm for non-midline dermoid cysts is presented. CT or MRI is recommended for lesions that are immobile, in atypical locations, or have associated periorbital sequelae or change with Valsalva. The authors feel there is no role for ultrasound and don't recommend routine imaging in patients with non-midline dermoid cysts without features suggestive of bony erosion.