Subperiosteal hematoma of the orbit following an aneurysm coiling procedure

To report a case of subperiosteal hematoma formation following endovascular stenting and coiling of an arterial aneurysm. Observational case report. A 51-year-old woman presented with complaints of sudden proptosis, ptosis, and severe orbital pain following endovascular stent placement and coiling procedure of an internal carotid artery aneurysm. The patient did not have a history of recent head trauma. Magnetic resonance imaging showed a superior subperiosteal hematoma of the left orbit with downward displacement of the left superior rectus muscle. No intervention was taken, and the patient was closely monitored. Her symptoms resolved after 4 weeks. Spontaneous subperiosteal hematoma in the absence of trauma is rare. This is the first reported case of subperiosteal hematoma formation following endovascular stenting and coiling of an arterial aneurysm, which may have been the manifestation of anticoagulation and changes in orbital hemodynamics during and after the procedure.