PARAGANGLIOMAS (CHEMODECTOMAS)

ANTHONY A. MANCUSO

KEY POINTS

Paragangliomas occur at many sites and pose significant treatment challenges in many cases if significant functional losses are to be avoided.
Precise imaging is critical to proper medical decision making.

PATTERNS OF DISEASE AND PATHOLOGY

Sites of Origin and General Classification

The neural crest cells give rise to what may be thought of as a multicentric organ system called the extra-adrenal paraganglia. In the head and neck region, these have basically two cell populations: chief cells storing granules of catecholamines and Schwann cell–like satellite cells. The paraganglia in the head, neck, and superior mediastinum are closely related to the major arteries and cranial nerves of the branchial arches and are therefore called the branchiomeric paraganglia, which closely resemble the carotid bodies in morphology. These paraganglia are chiefly involved in chemosensory phenomena and the regulation of blood flow.¹ Because of this function, they are highly vascular; this characteristic is reflected in the extreme hypervascularity of the neoplasms arising from the paraganglia. Some refer to these as chemodectomas. The term paraganglioma is used in this resource as the general term; the more popular, site-specific names are listed subsequently.

Normal glomus bodies are distributed throughout the head and neck. These tumors are most common at the carotid bifurcation and in the temporal bone and along the carotid sheath.²^–⁴ They are rare in the orbit, nasopharynx, larynx, sinonasal region, tongue, mandible, and trachea.

Temporal bone glomus bodies are distributed along the glossopharyngeal and vagus nerves. About one half of the glomus bodies are found in and around the jugular fossa within the adventitia of the jugular bulb. The remainder are distributed along the course of the Jacobson branch of the glossopharyngeal nerve; these lie in part along the inferior tympanic canaliculus and within the mucosa of the middle ear over the cochlear promontory, as discussed in Chapter 123. Glomus bodies are also located along the descending facial canal. The vagal glomus bodies lie in relationship to the vagal nodose ganglion or slightly lower. The carotid bodies are located at the carotid bifurcation. The glomus bodies of the orbit lie along the ciliary nerve. Glomus bodies in the larynx are mainly within the aryepiglottic fold.

The paraganglia give rise to the following tumors referred to by their most popular names (Figs. 33.1–33.7): carotid body tumor at the carotid bifurcation; glomus tympanicum in the middle ear; glomus jugulare in the jugular fossa; glomus vagale arising in the retrostyloid parapharyngeal space along the upper vagus nerve; orbital paraganglioma; and laryngeal paraganglioma, usually arising in the supraglottic larynx. Hybrid jugulotympanic tumors may extend from the bone lying between the carotid canal and jugular fossa into the hypotympanum (Fig. 33.3). These tumors arise from paraganglia in the inferior tympanic canaliculus along the Jacobson nerve. Alternatively, the term jugulotympanic has been used to lump all of the tumors that arise in conjunction with the temporal bone whose precise site of origin might be difficult to determine.

FIGURE 33.1. Contrast-enhanced computed tomography of a patient with a glomus jugulare type of paraganglioma. A, B: Anatomic diagram of sites of paraganglia in the neck and upper chest region to correlate with sites of origin of these tumors. C: The enhancing mass arises in the jugular fossa and extends below the skull base and also into the hypoglossal canal (arrows) compared to the normal hypoglossal canal on the opposite side (arrowhead). D: A component of the tumor projects intracranially and possibly intradurally (arrow) and grows along or within the inferior petrosal sinus (arrowhead). E: The bone windows demonstrate the typically aggressive erosive pattern (arrows) of paragangliomas within the skull base or other bony structures that they may involve. F: Bone windows to correlate with the image in (B) showing tumor growing into the inferior petrosal sinus (arrow) compared to the normal side (arrowhead). G: Continued growth of tumor in the inferior petrosal sinus (arrow). Such extension of tumor can significantly alter treatment decisions. H: Typical inferior extension of this mass within the retrostyloid parapharyngeal space and carotid sheath showing its tendency to somewhat incorporate the carotid artery as it grows (arrow). The jugular vein can either be invaded or displaced (arrowhead); in this case, the vein is more displaced than invaded, but invasion cannot be excluded (arrowhead).

FIGURE 33.2. Patient with a glomus jugulare type of paraganglioma, with computed tomography (CT) and magnetic resonance (MR) study for comparison. A: Bone windows show typical aggressive margins of bone destruction in areas of tumor involvement (arrows). B: Coronal CT with bone windows again showing margins of bone erosion in this patient, which is somewhat more sclerotic than usual (arrows). C: Non–contrast-enhancedT1-weighted (T1W) image showing the mass in the jugular fossa (arrow) and growing into the middle ear (arrowhead) flow voids are not obvious, but the mass is inhomogeneous. D: Contrast-enhanced T1W image showing enhancing tumor within the jugular fossa and middle ear cavity (arrows). Tumor also has grown within the sigmoid sinus (arrowhead). This pattern of growth explains the bone erosion demonstrated along the sigmoid plate in (A). There are still not obvious flow voids visible. E: T2-weighted MR image showing tumor in the locations (arrows) demonstrated by the contrast-enhanced image in (D). There still are no obvious flow voids. F: Contrast-enhanced T1W image showing the enhancing tumor in the jugular fossa and growing within the adjacent temporal bone (arrow). Flow voids are visible on this image as an aid to the differential diagnosis (arrowheads).

FIGURE 33.3. Non–contrast-enhanced computed tomography study of a patient presenting with pulse synchronous tinnitus and a mass visible behind the tympanic membrane on the right. A: A small mass projects anterior to the jugular bulb(arrow), which represents a superior extension of the paraganglioma. This was initially interpreted to be a glomus tympanicum tumor confined to the middle ear at another institution. B: This section demonstrates that the tumor actually is a paraganglioma that is not confined to the middle ear but grows along the bone between the carotid canal and the dome of the jugular fossa (arrow). C: Coronal image confirms tumor growing from beneath the promontory into the bone at the junction of the mastoid and petrous portion of the temporal bone (arrows). (NOTE: Jugulotympanic-type paragangliomas growing with this relatively limited extent are frequently mistaken for tumors isolated to the middle ear. Recognizing this spread pattern avoids errors in management.)

FIGURE 33.4. Patient presenting with a neck mass and no family history of paragangliomas or multiple endocrinopathy syndromes. Imaging showed that the neck mass was due to a carotid body type of paraganglioma. A second unsuspected unusual paraganglioma was also discovered. A: Reformatted images from a computed tomographic angiography study show the carotid body tumor situated at the carotid bifurcation between the external carotid and internal carotid arteries with typical displacement of those vessels (arrows). A second paraganglioma was identified at the foramen ovale (arrowheads), which is a very unusual location for such a lesion. B: Coronal contrast-enhanced computed tomography image shows the paraganglioma of the skull base situated at the foramen ovale causing it to be widened. C: Bone windows showing remodeling and erosion of bone extending from below the skull base inward as manifest by the upward displacement of the remodeled skull base (arrow). D: Contrast-enhanced T1-weighted coronal image showing a prominent vascular pedicle from the distal maxillary artery (arrows) and internal flow voids (arrowheads) helping with the differential diagnosis.

FIGURE 33.5. Magnetic resonance imaging study of a patient presenting with a left neck mass proven to be a carotid body tumor. A: T1-weighted (T1W) image without contrast showing a homogeneous mass (arrows) at the carotid bifurcation separating the internal and external carotid arteries (arrowheads). B: Contrast-enhancedT1W axial image showing a relatively homogeneous mass without obvious flow voids (arrow) with typical separation of the internal and external branches of the carotid artery (arrowheads).

FIGURE 33.6. A series of images demonstrating atypical behavior of a combined glomus vagale and carotid body tumor in a patient presenting with a neck mass. A: Non–contrast-enhanced computed tomography (CT)study showing a homogeneous mass at approximately the level of the carotid bifurcation. B: An image done during dynamic contrast injection showing that the mass enhances much more peripherally than centrally. C: A series of images from the dynamic CT study showing the pattern of predominantly peripheral and lack of central enhancement. D: The series of curves generated from the dynamic study comparing the mass enhancement, with that of vessels and muscle showing the center of the mass to be relatively hypovascular, which is atypical of paraganglioma. E: Contrast-enhancedT1-weighted magnetic resonance study showing anatomic findings consistent with paraganglioma and an inhomogeneous pattern possibly due to flow voids. F, G: Digital and direct catheter angiograms, respectively, showing the mass to be essentially hypovascular. (NOTE: Anatomically, this was felt to be a carotid body tumor but morphologically was possibly more consistent with a schwannoma. At surgery, the mass was a paraganglioma with enhancing tissue at the periphery and dominant central core of fibrous tissue that was minimally vascular. This is an example of atypical enhancement pattern in a paraganglioma.)

FIGURE 33.7. Patient presenting with hoarseness and a submucosal laryngeal mass. This was proven by imaging to be a paraganglioma of the supraglottic larynx.This contrast-enhanced computed tomography study shows the markedly enhancing supraglottic mass (arrow) in the left paraglottic space and the markedly enlarged left superior laryngeal neurovascular bundle (arrowheads). (NOTE: The diagnostic imaging avoided what might have been a troublesome biopsy procedure. Diagnosis was eventually confirmed angiographically, and the patient was treated by surgical resection that confirmed paraganglioma.)

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