Primary adenocarcinoma of the temporal bone mimicking paragangliomas: radiographic and clinical recognition.

Three cases of primary adenocarcinoma of the temporal bone which simulated a glomus jugulare tumor (on the basis of a thorough preoperative evaluation) are detailed. In each case, a vascular mass was seen beneath an intact tympanic membrane and angiography revealed the presence of a highly vascular mass centered on the jugular bulb. Computed tomography revealed erosive changes within the jugular fossa that were characteristic of a glomus jugulare tumor; in two cases, a significant posterior fossa extension was documented. The intraoperative findings failed to suggest a lesion different from paraganglioma in two of the cases; in the remaining case, the erosion of both bone and dura was diffuse and more suggestive of a malignant neoplasm. A discussion of the clinical behavior of adenocarcinomas of the middle ear is included in order to emphasize the importance of differentiating these lesions preoperatively from the more commonly encountered paragangliomas.