Serial Magnetic Resonance Imaging Leading to the Diagnosis of a Growing Skull Fracture in an Infant Without an Apparent Fracture Widening on Follow-Up Computed Tomography.

A growing skull fracture (GSF), an infrequent complication of skull fractures in infancy and early childhood, is characterized by progressive fracture diastasis, dural defect, and meningeal and/or brain parenchymal herniation. We report the case of a three-month-old girl who developed GSF following head trauma. She was brought to our hospital because of decreased responsiveness after falling down the stairs while being carried by her mother. Initial head computed tomography (CT) revealed a right temporoparietal skull fracture with diastasis measuring 7-8 mm, acute subdural hematoma, traumatic subarachnoid hemorrhage, intraventricular hemorrhage, and bilateral parietal contusions. The acute phase was conservatively managed without clinical deterioration. On hospital day 8, magnetic resonance imaging (MRI) suggested dural injury and brain herniation at the fracture site. Although follow-up CT on day 27 post-injury demonstrated no apparent fracture widening, MRI on day 48 revealed clear dural disruption and cyst formation, resulting in the diagnosis of GSF. Cranioplasty was performed 75 days post-injury, and the postoperative course was uneventful. This case suggests that reliance on CT findings alone may delay GSF diagnosis in selected high-risk infants. In such patients, early and repeat MRI, timed according to the clinical and radiological course, may assist in detecting dural disruption, brain herniation, or cyst formation before obvious fracture progression becomes apparent on CT. The imaging intervals used in this patient should be interpreted as case-informed rather than as a validated surveillance protocol.