Diagnosis

A jugulotympanic paraganglioma has such a characteristic oto-scopic appearance that there is seldom an indication for a biopsy. A high jugular bulb might be mistaken for the superior pole of jugular paraganglioma; however, its smooth, pale blue margin helps distinguish it from a tumor. Although another middle ear neoplasm can mimic a paraganglioma, there is frequently something in the clinical history or examination that just does not fit that of the more common paraganglioma. Thus far, I have not had to biopsy a middle ear mass that I believed was a paraganglioma in order to formulate a treatment plan. Instead, I have frequently complemented the clinical findings with a radiologic evaluation that might include computed tomography (CT), magnetic resonance imaging (MRI), and angiography. However, not every patient suspected of having a jugulotympanic paraganglioma requires neuroradiologic evaluation. I believe, for example, that a patient with a small tympanic paraganglioma that can be seen in its entirety requires no additional evaluation. When the margins of a tumor are obscure, however, I do recommend a radiographic examination. The frequency with which improvements are made in imaging technology preclude insistence on one imaging technique over another. From my perspective, the choice of an initial imaging modality should be based on the information needed, the availability of imaging equipment, and the level of knowledge and experience of the consulting radiologist.

I still use high-resolution computed tomography (HRCT) of the cranial base with contrast enhancement as an initial imaging tool. Whether the lesion is a large tympanic paraganglioma or a sizable jugular variant is not therapeutically important to me. I have found that the study gives me a reliable assessment of the integrity of bone in the area of the jugular fossa, the carotid canal, and the facial canal, as well as an estimate of the extent of the neoplasm.

If the information derived from CT is equivocal or incomplete, I then use gadolinium-enhanced MRI for its superior soft tissue contrast resolution. MRI, for example, can distinguish between tumor and a serous or mucoid effusion, fat, muscle, and brain. I also use MRI to screen for synchronous tumors when clinically indicated. Finally, I use this imaging technique to screen for residual or recurrent disease, particularly if the patient has had prior treatment.

Early on, I had almost every patient with a large jugulo-tympanic tumor go through carotid and vertebral arteriography, regardless of what vascular structures were involved. I am still not sure of the origin of this philosophy. It may have evolved as a result of using the vertebral study to assess whether a tumor extended through the posterior cranial fossa and using the venous phase of the arteriogram to determine the status of the venous return. When there was radiologic evidence of encroachment of the carotid canal, I usually requested an assessment of the patient's tolerance to carotid artery sacrifice in the study. Over the course of 15 years, however, I have learned that

(1) arteriography, especially carotid artery occlusion testing, has a known morbidity, regardless of how the patient is monitored;

(2) I have yet to resect an internal carotid artery in a patient with a paraganglioma; (3) the one death I have witnessed was a young woman who passed carotid occlusion testing and died of postoperative stroke due to an embolus that developed behind a transiently constricted internal carotid artery2; (4) when coupled with CT and MRI findings, the information I obtained from angiography has not changed my treatment recommendations; and (5) the study is not cheap. Today, I use angiography in the context of adjuvant or therapeutic embolization to decrease the blood supply to a paraganglioma.

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