Ultrasound for the Preoperative and Intraoperative Management of Pediatric Scalp Masses

Introduction: Calvarial dermoid and epidermoid cysts are benign congenital masses common in pediatric neurosurgery. Management typically involves surgical resection to confirm diagnosis and prevent future growth. Diagnosis is usually clinical, with frequent yet inconsistent use of imaging for confirmation. Distinct sonographic features allow for diagnosis confirmation and aid in ruling out other pathologies, such as lymph nodes and encephaloceles. Despite this, ultrasound (US) remains highly underutilized in the pre- and intra-operative management of these lesions.

Methods: A retrospective review of consecutive patients up to 3 years of age with clinically suspected calvarial dermoids between 2020-2022 was performed. Demographic, imaging, and pathology data were studied. Cases initially suspected to be a different pathology and later found to be a different diagnosis (encephaloceles, Langerhans cell histiocytosis, etc..) were excluded.

Results: Eighteen patients (10 females, 8 males; mean age 13.9 ± 6.8 months) were included in the analysis. US was used preoperatively or intraoperatively in all but four cases and was the sole imaging modality in six. Sonography of the cysts demonstrated anechoic to hypoechoic oval lesions (average size 1.6 x 1.1 x 0.7 cm) between the pericranium and bone with no vascular flow on Doppler. Dermoid or epidermoid cyst was the preoperative diagnosis in all 18 cases and the confirmed final diagnosis in 17, including all cases with US as the sole imaging.

Conclusion : With rare exceptions, US presents a sensitive and reliable method for the evaluation of pediatric scalp lesions, especially dermoid and epidermoid cysts, and warrants being part of their standard workup. When supplemented with doppler imaging, US obviates the need for additional, more invasive imaging in pediatric patients, including CT (radiation) and MRI (sedation). US may be used pre-operatively to assess lesions’ echogenicity, vascularity, bony impression, and relationship with the pericranium, and may guide surgical approach intra-operatively.