ndré J. Macdonald 1 Karen L. Salzman 1 H. Ric Harnsberger 1 Erik Gilbert 2 lough Shelton 2 Received May 16, 2003; accepted after revision ugust 12, 2003. 1 Department of Diagnostic Radiology, University of Utah, 171 Medical enter, 50 N Medical Dr., Salt Lake ity, UT 84132. ddress correspondence to K. L. Salzman. 2 Department of Otolaryngology, University of Utah, Salt Lake ity, UT 84132. JR 2004;182:373 377 0361 803X/04/1822 373 merican Roentgen Ray Society Primary Jugular Foramen Meningioma: Imaging ppearance and Differentiating Features OJETIVE. Primary jugular foramen meningiomas behave differently from meningiomas arising elsewhere. The differences have important clinical, imaging, and surgical implications. We reviewed the imaging appearances of primary jugular foramen meningiomas and evaluated them for features that might assist in differentiating them from other common jugular foramen lesions. MTERILS ND METHODS. retrospective review identified five cases of primary jugular foramen meningioma. We defined it as primary when it was centered in the jugular foramen and secondary when it was centered in the posterior fossa with secondary extension into the jugular foramen. Secondary jugular foramen meningiomas were excluded from this study. Eight cases of jugular foramen paraganglioma and 10 cases of jugular foramen schwannoma were reviewed for comparison. RESULTS. Primary meningioma was characterized by centrifugal infiltration surrounding the skull base (5/5), a permeative sclerotic appearance to the bone margins of the jugular foramen (5/5), and prominent dural tails (5/5). Flow voids were absent in all cases. Paraganglioma showed localized skull base infiltration, with predominant superolateral spread into the middle ear cavity (8/8). Flow voids and permeative destruction of the bone margins of the jugular foramen were typical. Schwannoma caused expansion of the jugular foramen with scalloped well-corticate bone margins, without skull base infiltration. ONLUSION. Primary jugular foramen meningioma is characterized by extensive skull base infiltration. centrifugal pattern of spread, a permeative sclerotic appearance of the bone margins of the jugular foramen, the presence of dural tails, and an absence of flow voids are particularly important features that assist in differentiating primary jugular foramen meningioma other more common jugular foramen lesions. P rimary jugular foramen meningioma is a common tumor in an unusual location [1, 2]. Meningiomas arising primarily in the jugular foramen appear to behave differently from meningiomas that involve the jugular foramen secondarily [1, 3, 4]. Primary jugular foramen meningiomas are characterized by extensive skull base infiltration, which results in important clinical, surgical, and imaging differences between them and typical meningiomas that arise elsewhere. lthough the clinical, surgical, and imaging characteristics of classic meningioma are well known, diffusely infiltrating lesions arising in the jugular foramen have received relatively little attention. Recent reviews in the neurosurgical literature [1] and at an otology meeting (Gilbert E et al., presented at the 2002 Triological Society Western Section meeting) have highlighted the important treatment and surgical issues. oth reviews emphasized the importance of accurate preoperative imaging. We reviewed the clinical and radiologic records of five cases of primary jugular foramen meningioma. The T and MRI findings in these cases were then contrasted with the radiologic features of the two other lesions most commonly found in the jugular foramen: paraganglioma and schwannoma [1, 5 7]. We found important differentiating imaging features. Materials and Methods We identified five cases of surgically treated and pathologically confirmed primary jugular meningioma with available imaging studies in the records of our institute from the past 7 years. Meningiomas were defined as primary when they were centered in the jugular foramen and secondary when they were centered in the posterior fossa with secondary extension into the jugular foramen. Meningiomas with secondary involve- JR:182, February 2004 373
Macdonald et al. Records of five patients with primary jugular foramen meningioma were reviewed. The pa- tients ranged in age from 31 to 60 years (mean, 52 years); two were men and three were women. linical information was available for four of the five patients. The most common presenting symptom was sensorineural hearing loss, found in two patients (2/5). Other symptoms included pulsatile tinnitus (1/5), facial nerve weakness (1/5), chronic otitis media (1/5), and dizziness (1/5). Findings on clinical examination included a retrotympanic mass in two patients (2/5), deficits of the seventh cranial nerve in one patient (1/5), and deficits of the ninth 11th cranial nerves in another patient (1/5). Records of eight patients with jugular foramen paraganglioma were reviewed. The patients were between 32 and 76 years old (mean, 56 years); three patients were men, five were women. linical information was available for seven (7/8). ll (7/7) presented with pulsatile tinnitus, with varying hearing loss noted in four patients (4/7). One patient (1/7) complained of facial numbness. Otoscopic examination revealed a retrotympanic mass in all patients (3/3) for whom an otoscopy report was available. ment of the jugular foramen were excluded from this review. lso included from the same time period were eight cases of jugular foramen paraganglioma, and 10 cases of schwannoma selected randomly from our imaging database to compare and identify helpful differentiating imaging features. Institutional review board approval was obtained. linical data including demographic information and presenting features were reviewed in all cases if they were available. ll patients underwent T, MRI, or both. lthough some individual scanning parameters varied, unenhanced axial thin-section bone-only T and multiplanar MRI using unenhanced T2-weighted, T1-weighted, and gadoliniumenhanced fat-saturated T1-weighted sequences were performed in all cases. Images were analyzed for anatomic location and structure, with specific attention to those characteristics that might assist in differentiation. Special attention was given to the presence or absence of high-velocity flow voids on MRI and the bone margins of the jugular foramen on T scans. The direction of growth was also analyzed. Results Demographic Data, Symptoms, and linical Findings Records of 10 patients with jugular foramen schwannoma were reviewed. They were between 32 and 65 years old (mean age, 47 years); eight were men, two were women. linical information was available for nine (9/10). Presenting symptoms included hoarseness (4/ 9), arm weakness (2/9), hearing loss (1/9), tinnitus (1/9), and tongue weakness (1/9). linical findings included deficits of the 10th (4/9), 11th (2/9), and 12th (3/9) cranial nerves. Imaging Findings Primary jugular foramen meningioma. Primary jugular foramen meningiomas were characterized by extensive infiltration of the surrounding skull base (5/5) with involvement of the middle ear cavity (5/5), internal auditory canal (5/5), hypoglossal canal (5/5), clivus (4/5), carotid space (5/5), and posterior fossa (5/5) (Figs. 1 1). Tumor in the temporal bone spared the otic capsule and spread into the hypotympanum in all cases. In two cases (2/5) the tumor completely engulfed the ossicles without demineralizing or destroying them. Extracranial soft-tissue extension was confined to the na- Fig. 1. Primary jugular foramen meningioma in 60-year-old woman., oronal unenhanced T1-weighted image shows mass centered in jugular foramen (star) with extensive surrounding infiltration of skull base. Note medial infiltration into jugular tubercle and occipital condyle with replacement of normal hyperintense marrow (solid arrow), spread into posterior fossa and into internal auditory canal (open arrow), lateral spread into middle ear cavity, and inferior involvement of nasopharyngeal carotid space. lso note absence of high-velocity flow voids., oronal contrast-enhanced fat-saturated T1-weighted image obtained slightly anterior to shows intense enhancement and extensive infiltration of surrounding skull base. Note spread into posterior fossa (thin black arrow), lateral spread into middle ear cavity (white arrow), and inferior involvement of nasopharyngeal carotid space (thick black arrow)., xial contrast-enhanced fat-saturated T1-weighted image shows en plaque involvement of posterior fossa with prominent dural tails, medial spread in skull base to mid clivus (solid arrow), and tumor in middle ear cavity that engulfs ossicles (open arrow). D, one window image from unenhanced axial T scan shows margins of jugular foramen (star) to be slightly irregular with loss of normal cortex. Infiltrated skull base shows relatively well-preserved bone density and bone architecture, resulting in characteristic permeative sclerotic appearance. D 374 JR:182, February 2004
Primary Jugular Foramen Meningioma Fig. 2. Jugular foramen paraganglioma in 44-year-old woman., oronal unenhanced T1-weighted image shows mass centered in jugular foramen with prominent vascular flow voids (arrow)., oronal contrast-enhanced fat-saturated T1-weighted image shows intensely enhancing mass centered in jugular foramen (star) with superolateral spread into hypotympanum (arrow). Spread into posterior fossa and medial skull base is limited., one window image from unenhanced coronal T scan shows permeative erosion of margins of jugular foramen (arrow) without sclerosis. Note soft tissue in hypotympanum. sopharyngeal carotid space without invading the surrounding soft tissues of the deep spaces of the suprahyoid neck. Posterior fossa involvement had an en plaque appearance in four cases (4/5) and a globose appearance in one (1/5). ll cases (5/5) showed prominent dural tails. On MRI, jugular foramen meningiomas appeared as isointense to hypointense in signal intensity on T1-weighted sequences and intermediate in signal intensity on T2-weighted sequences, with no flow voids noted. ll meningiomas (5/5) showed intense uniform enhancement after contrast administration. On T, all meningioma cases (5/5) had a permeative, irregular appearance to the bone margins of the jugular foramen and surrounding skull base, with relative preservation of bone density and bone architecture (Fig. 1D). Jugular foramen paraganglioma. Paraganglioma was characterized by localized skull base infiltration with predominant superolateral spread involving the middle ear cavity (8/8). Medial spread with involvement of the hypoglossal canal (2/8), jugular tubercle (2/8), and clivus (0/8) was less common (Figs. 2 and 2). Limited spread inferiorly into the nasopharyngeal carotid space (8/8) was typical. Posterior fossa extension and dural tails were not present. ll cases involved the middle ear cavity, with most (7/8) confined to the hypotympanum. One case involved ossicles that remained intact, without erosion or sclerosis. ll paragangliomas with available MRI studies (6/8) showed the presence of flow voids (Fig. 2) with intense enhancement after contrast administration. ll paragangliomas with available T scans (7/8) revealed permeative destruction of the bone margins of the jugular foramen and loss of bone density in the affected bone (Fig. 2). Jugular foramen schwannoma. Schwannomas caused expansion of the jugular foramen without invasion of the marrow space (10/10). Schwannomas typically involved the nasopharyngeal carotid space (8/10) and posterior fossa (6/10) with no involvement of the temporal bone or clivus (Figs. 3 and 3). One large schwannoma extended into the hypoglossal canal. Extension into the posterior fossa occurred in the direction of the lateral brainstem. On MRI, all schwannomas were lobulated, well circumscribed, and hyperintense on T2weighted images, and without flow voids or dural tails. ll schwannomas with available Fig. 3. Jugular foramen schwannoma in 53-year-old man., xial contrast-enhanced fat-saturated T1-weighted image shows intensely enhancing well-circumscribed jugular foramen mass (star) with extension into posterior fossa (arrow) toward lateral medulla. No skull base infiltration is present., Sagittal contrast-enhanced T1-weighted image shows inferior involvement of nasopharyngeal carotid space with anterior displacement of carotid artery (arrow)., one window image from unenhanced axial T scan shows expansion of jugular foramen with preservation of cortex (arrow). No bone infiltration is present. JR:182, February 2004 375
Macdonald et al. Fig. 4. Typical growth patterns of primary jugular foramen meningioma, paraganglioma, and schwannoma. (Reprinted with permission from [10]), Drawing shows primary jugular foramen meningioma with centrifugal infiltration surrounding skull base including lateral spread into hypotympanum, medial spread into jugular tubercle and hypoglossal canal, inferior involvement of carotid space, and dural-based involvement of posterior fossa., Drawing shows jugular foramen paraganglioma as vascular mass infiltrating surrounding skull base with superolateral growth into hypotympanum of middle ear cavity., Drawing shows jugular foramen schwannoma as well-circumscribed fusiform mass with superomedial growth toward lateral medulla along course of cranial nerves 9 11. Jugular foramen is enlarged with well-corticate bone margins. Primary jugular foramen meningioma is a common tumor in an unusual location [1, 2]. Meningiomas arising primarily in the jugular foramen are characterized by diffuse skull base infiltration [1, 3, 4]. This locally invasive tendency differentiates primary jugular foramen meningioma from meningioma that involves the jugular foramen secondarily. It also results in important clinical, surgical, and radiologic differences between primary jugular foramen meningioma and the other common lesions of the jugular foramen. Furthermore, differentiation of primary jugular foramen meningioma from the more common jugular foramen masses, specifically paraganglioma and schwannoma, has important prognostic and therapeutic implications [1], which increases the importance of preoperative diagnosis. condyle, and clivus medially. Inferior extracranial spread occurs into the nasopharyngeal carotid space of the deep suprahyoid neck, and superior intracranial spread is seen along the intracranial dural reflections. This spread along the dura is termed en plaque and is characteristic of primary jugular foramen meningiomas. globose appearance is seen less commonly. The spread pattern is different in jugular foramen paraganglioma, which typically extends from the jugular foramen in a superolateral direction to involve the hypotympanum of the middle ear cavity (Fig. 4). Limited involvement of the nasopharyngeal carotid space was present inferiorly in all cases. Medial spread into the jugular tubercle, hypoglossal canal, and clivus occurred infrequently. Superior spread with intracranial extension was not seen with jugular foramen paraganglioma. Jugular foramen schwannomas follow the course of the glossopharyngeal, vagus, and accessory cranial nerves from which they arise. They therefore typically extend in a superomedial direction toward the lateral aspect of the brainstem, with variable inferior spread into the nasopharyngeal carotid space of the suprahyoid neck (Fig. 4). Direction of Growth Skull ase Infiltration Primary jugular foramen meningiomas infiltrate the surrounding skull base in all directions (Fig. 4). This pattern of spread can be referred to as centrifugal. The spread pattern involves the temporal bone including the middle ear cavity laterally and invades the skull base including the jugular tubercle, hypoglossal canal, occipital Primary jugular foramen meningiomas typically infiltrate the surrounding skull base diffusely in a pattern similar to meningioma of the sphenoid bone characterized by primary intraosseous spread, so-called hyperostosing meningioma en plaque [3, 4, 8]. This infiltrative behavior seems different from the growth pattern of the more typi- gadolinium-enhanced T1-weighted studies (8/ 10) showed intense enhancement. ll schwannomas for which T scans were available (8/ 10) had scalloped well-corticate bone margins without adjacent marrow space involvement (Fig. 3). Discussion 376 cal meningiomas, including meningiomas with secondary jugular foramen involvement, which are typically dominated by a soft-tissue mass and have limited bone involvement. Glomus jugulotympanicum paraganglioma also typically infiltrates the skull base, preferentially involving the superior and lateral margins of the jugular foramen. Jugular foramen schwannoma does not infiltrate the diploic space of the surrounding skull base. lthough large tumors may result in marked enlargement of the jugular foramen, no infiltration into the surrounding bone is present. one hanges In cases in which the diploic space of the skull base is widely infiltrated by primary jugular foramen meningioma, the bone architecture and density tend to be preserved [3]. Marked bone hyperostosis, which has been shown to result from direct tumor infiltration [9] and tumor matrix calcification, was not a typical feature in our cases. The margins of the jugular foramen are typically irregular with loss of the normal cortex. This combination of findings, neither permeative nor sclerotic, yet with features of both, results in a permeative sclerotic appearance on T (Fig. 1D). This characteristic appearance was seen in all our cases of primary jugular foramen meningioma and is quite different from the pattern seen with paraganglioma and schwannoma. Paragangliomas may show a permeative destructive pattern with erosion of the jugular foramen margins and infiltrated bone without preservation of the underlying architecture or bone density (Fig. 2). Schwannoma gradu- JR:182, February 2004
Primary Jugular Foramen Meningioma ally enlarges the jugular foramen by pressure erosion and gives an expanded and scalloped but well-defined corticate margin to the jugular foramen (Fig. 3). Other Differentiating Features Vascular flow voids shown on MRI are characteristic of paraganglioma (Fig. 2). ll paragangliomas we reviewed on MRI showed these high-velocity flow voids, but the primary jugular foramen meningiomas did not (Fig. 1). This differential feature may help in arriving at the preoperative diagnosis of jugular foramen meningioma, as may the presence of dural tails. onclusion diagnosis of primary jugular foramen meningioma can often be made preoperatively when several radiologic features are seen associated with a jugular foramen mass: on T, extensive surrounding skull base infiltration in a centrifugal spread pattern, an associated permeative sclerotic appearance in the affected bones; on MRI, the absence of high-velocity flow voids and the presence of dural tails. Together these are highly suggestive of primary jugular foramen meningioma. References 1. rnautovic K, l-mefty O. Primary meningiomas of the jugular fossa. J Neurosurg 2002;97:12 20 2. Roberti F, Sekhar L, Kalavakonda, Wright D. Posterior fossa meningiomas: surgical experience in 161 cases. Surg Neurol 2001;56:8 20 3. Molony T, rackmann D, Lo W. Meningiomas of the jugular foramen. Otolaryngol Head Neck Surg 1992;106:128 136 4. Nager G, Heroy J, Hoeplinger M. Meningiomas invading the temporal bone with extension to the neck. m J Otolaryngol 1983;4:297 324 5. aldemeyer K, Mathews V, zzarelli, Smith R. The jugular foramen: a review of anatomy, masses, and imaging characteristics. Radio- Graphics 1997;17:1123 1139 6. Rao, Koeller K, dair. Paragangliomas of the head and neck: radiologic pathologic correlation. RadioGraphics 1999;19:1605 1632 7. Eldevik P, Gabrielsen T, Jacobsen E. Imaging findings in schwannomas of the jugular foramen. JNR 2000;21:1139 1144 8. harbel F, Hyun H, Misra M, Gueyikian S, Mafee R. Juxtaorbital en plaque meningiomas: report of four cases and review of the literature. Radiol lin North m 1999;37:89 100 9. Pieper D, l-mefty O, Hanada Y, uechner D. Hyperostosis associated with meningioma of the cranial base: secondary changes or tumor invasion. Neurosurgery 1999;44:742 746 10. Harnsberger HR. Head and neck digital teaching file. Salt Lake ity, UT: dvanced Medical Imaging Reference Systems, 2003 JR:182, February 2004 377