Fibrous dysplasia of occipital bone revealed by acute intracranial hypertension.

Fibrous dysplasia of bone is a stem cell bone disease due to a somatic GNAS mutation which can affect craniofacial bones. Although craniofacial fibrous dysplasia is a benign and progressive disorder, it can cause mass effect on the cranial structures. We describe an 18-year-old man, without past medical history, came at the emergency department with progressively worsening headache, associated with vomiting. Cranial bone CT and then brain MRI revealed fibrous dysplasia of occipital bone with intraosseous cyst, compression of right sigmoid vein. An angiography was performed to stent the right sigmoid vein and symptoms had completely resolved only a few hours after the procedure. Then, a treatment by bisphosphonates was introduced. We believe this is the first description of sigmoid vein compression by a bone cyst, requiring stenting. MRI should be performed urgently in case of unusual severe headache or rapidly evolving neurologic impairment in patients with craniofacial fibrous dysplasia. Treatment of fibrous dysplasia is a controversial subject. In cases with neurologic complications, surgery or endovascular treatment might be performed.