RESUMEN
Primary delayed onset craniosynostosis is a rarely reported phenomenon. The unique case of a 2-year-old boy who had computed tomography (CT) scans performed 20 months apart demonstrating the post-gestational development of sagittal suture craniosynostosis is presented. The otherwise healthy male initially presented to the emergency department at age 7 months with soft tissue swelling over his left parietal region secondary to a fall. A CT scan revealed a possible left parietal skull fracture without intracranial pathology and patent cranial sutures with a normocephalic calvarial configuration. Twenty months later, his paediatrician referred the boy to the craniofacial service for evaluation of progressive dolichocephaly. A new CT scan showed complete fusion of the sagittal suture with resultant biparietal narrowing, frontal bossing, and occipital prominence. The patient subsequently underwent uncomplicated frontoparietal craniotomy with calvarial vault reconstruction. Prior reports in the literature of cases of non-syndromic primary delayed onset craniosynostosis all lack 'pre-synostosis' CT imaging that proves post-birth patency of the cranial sutures. This case report documents CT demonstrating true primary delayed onset craniosynostosis.