Case report: The authors present a rare case of ossified chronic epidural hematoma. A 13-year-old female patient presented with an ossified chronic epidural hematoma. She had sustained a head injury about 10 weeks previously and had received conservative care for a delayed-onset epidural hematoma at a local hospital. Ossification was identified about 4 weeks after the head injury and then progressed rapidly. A chronic epidural hematoma with a thick collagenous capsule and newly formed bone was removed 73 days after the head injury.
Conclusion: An epidural hematoma with mild symptoms can be treated conservatively. When, however, the hematoma is observed not to be naturally absorbed during serial follow-up examinations, surgical removal must be considered, even if the patient's condition is good, because this entity carries the risk of bone calcification and ossification.