Pulsatile Tinnitus Caused by Highly Vascularized Fibrous Dysplasia of Temporal Bone with Centrally Located Fibrous Cyst

To date, the management and mechanism of pulsatile tinnitus (PT) caused by fibrous dysplasia (FD) of the temporal bone have not been discussed in detail. Therefore, this study is carried out to introduce PT secondary to monostotic temporal bone FD with cystic and lytic development in simultaneity complicated by the expansile bone lesion compressing over the sigmoid sinus. A 46-year-old female patient diagnosed with FD presented with severe persistent PT seeking medical assistance. Radiologic modalities displayed a 74.3 cm3 monostotic FD with a presumably high-vascularity lytic change of the bone lesion located in the posterior portion of the mastoid cavity. The patient’s PT was non-pulse-synchronous and was irrelevant to the intracranial blood flow revealed by ultrasonographic examination. A subtotal petrosectomy was performed after a meticulous preoperative assessment. During surgery, an unprecedented elastic cystic structure with three pedicles filled with vascular fluid was appreciated at the center of the FD lesion. PT was resolved after the removal of 90.8% of the total volume of the highly vascularized low-bone mineral density fibro-osseous tissues and the fibrous cyst. There were no PT reoccurrence and no postoperative complications during a two-month follow-up. Albeit rarely encountered, caution is required as PT secondary to FD is highly associated with the vascularity of the bone lesion.