Supplementary Material for: Management of Congenital Occipital Exostosis in the Pediatric Patient: Illustrative Case Report

Background The authors present a case of a 2-week-old male referred for neurosurgical evaluation after occipital bony prominences were detected on a postnatal exam. The patient was born full term via uncomplicated vaginal delivery and underwent a head ultrasound, which disclosed an occipital heterotopic ossification. Physical exam revealed dimpling bilaterally over bony prominences at the occiput. CT and MRI confirmed symmetric exostoses without clear intracranial involvement. However, fibrous adhesions were noted extending through the dermis, suggesting dermal involvement likely secondary to the bony changes, although no definitive sinus tracts were identified. The patient was monitored for the first year of life with no symptoms or developmental concerns. At follow up at 15 months of age, the bony prominences and overlying fat pad were noticeably enlarged, which prompted corrective surgery. The exostosis was excised to restore normal occipital contour, and excess fat and skin were removed. Pathology revealed cartilage, cortical and trabecular bone, hematopoiesis, and mild intramedullary fibrosis. The surgery was successful with no complications, and the patient had an uneventful recovery. Observations Postoperatively, the patient continues to meet developmental milestones without neurological deficits or complications. Lessons This case highlights the surgical management of an unusual occipital exostosis in an asymptomatic pediatric patient. It underscores the importance of individualized preoperative planning, comprehensive imaging, and ongoing clinical monitoring to assess changes over time.