Choroid plexus papilloma and meningioma: coincidental posterior fossa tumors

Neoplasm

Choroid plexus Papilloma and Meningioma: Coincidental Posterior Fossa Tumors CASE REPORT AND REVIEW OF THE LITERATURE Jon I. McIver, M.D.,* Michael J. Link, M.D.,* Caterina Giannini, M.D.,† Aaron A. Cohen-Gadol, M.D.,* and Colin Driscoll, M.D.‡ *Departments of Neurosurgery, †Pathology, and ‡Otorhinolaryngology, Mayo Clinic, Rochester, Minnesota

McIver JI, Link MJ, Giannini C, Cohen-Gadol AA, Driscoll C. Choroid plexus papilloma and meningioma: coincidental posterior fossa tumors. Case report and review of the literature. Surg Neurol 2003;60:360 –5. OBJECTIVE

We report an unusual case of an extraventricular choroid plexus papilloma (CPP) occupying the right ventral foramen magnum and lower right cerebellopontine angle (CPA), occurring together with a petro-tentorial meningioma. The clinical presentation, preoperative imaging, differential diagnosis, surgical treatment and histologic features of the two tumors are discussed. CASE DESCRIPTION

The patient presented with a 2-month history of headache, altered facial sensation, dysphagia, and gait unsteadiness. Neurologic examination confirmed a widebased, unsteady gait, hoarse voice, anisocoria, and partial right vocal cord paralysis. Diagnostic imaging demonstrated right petro-tentorial and right ventral foramen magnum lesions, both hyperintense on contrasted images and suggestive of meningiomas. A right suboccipital craniotomy and far lateral approach was used to resect both tumors. The petro-tentorial tumor was a histologically confirmed meningioma, but the ventral foramen magnum tumor was an extraventricular CPP. CONCLUSION

This is a rare occurrence of concomitant meningioma and CPP. There is no known link between these two tumors. An exophytic 4th ventricular CPP must be considered in the differential diagnosis of a CPA or foramen magnum tumor. © 2003 Elsevier Inc. All rights reserved. KEY WORDS

Cerebellopontine angle, choroid plexus papilloma, foramen magnum, far lateral approach, meningioma.

Address reprint requests to: Dr. Michael J. Link, Department of Neurosurgery, Mayo Clinic, 200 First Street, S.W., Rochester, MN 55905. Received October 29, 2002; accepted January 20, 2003. 0090-3019/03/$–see front matter doi:10.1016/S0090-3019(03)00157-5

eningiomas are among the most common intracranial tumors, accounting for approximately 20% of all primary brain tumors [5]. The majority are located in the supratentorial compartment and only 10% of all intracranial meningiomas arise within the posterior fossa with the following pattern of distribution: 50% located in the cerebello-pontine angle (CPA), 40% arising from the tentorium or cerebellar convexity, 9% petroclival, and 4% at the foramen magnum [5]. Choroid plexus papillomas (CPP) are rare benign tumors, accounting for less than 1% of intracranial tumors in adults [2]. In childhood, these tumors usually arise within the lateral ventricles, most frequently at the level of the atrium. In adults, they most often occur in the fourth ventricle and/or its lateral recesses [2]. Primary extraventricular locations of CPP are rare and mostly found in the CPA [12]. We report an unusual case of an extraventricular CPP, located primarily at the foramen magnum occurring concurrently with a petro-tentorial meningioma within the posterior fossa.

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Clinical Presentation HISTORY A 45-year-old right-handed woman presented with a 2-month history of nocturnal occipital headaches, altered sensation of the right side of her face, and intermittent sharp pain of the right eye. She reported for medical evaluation secondary to a 1-month history of progressive difficulty swallowing and gait unsteadiness. In retrospect, she related an © 2003 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010 –1710

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(A) (Axial) and (B) (Coronal). Axial and Coronal Gadolinium enhanced T1WI demonstrates an intensely enhancing jugular tubercle region lesion compressing the brainstem. The mass abuts the dura of the inferolateral right portion of the clivus and jugular tubercle. There is an associated area of hypodensity consistent with calcification.

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episode of “laryngitis” 1 year earlier from which her voice did not completely recover. She had a 38 pack-year history of cigarette smoking. Cranial nerve examination demonstrated anisocoria with a pupil diameter of 3 mm on the right and 5 mm on the left. Decreased sensation in the oropharynx and decreased motion of the right vocal cord was demonstrated by flexible fiberoptic laryngoscopy. She reported subjective decreased sensation in the right face but had no objective sensory deficits. Extraocular movements, hearing, facial, tongue, trapezius, and sternocleidomastoid motor functions were normal. Muscle strength was normal in all four extremities and she had no long tract signs. Her gait was slightly wide-based. She had no abnormal skin pigmentation or stigmata of neurofibromatosis. NEURORADIOLOGY A magnetic resonance imaging (MRI) scan of the brain revealed a 5 ⫻ 4 ⫻ 4 cm mass, apparently based on the jugular tubercle, occupying the right

inferior CPA and ventral foramen magnum compressing the cervico-medullary junction (Figure 1). The tumor enhanced intensely after administration of gadolinium. An 8 mm area extending into the cerebellum, with low T1 and T2 signal consistent with calcification was noted. A separate, 2.5 ⫻ 2 ⫻ 2 cm, homogeneously enhancing mass was present at the petro-tentorial junction anterior to the transverse-sigmoid sinus junction (Figure 2). These lesions appeared radiographically separate based on the MRI scans. A MRI limited to the cervical spine performed 2 years before for cervical radiculopathy did not show evidence of the foramen magnum lesion. On cerebral angiography, the foramen magnum lesion received the majority of arterial supply from the right vertebral artery via meningeal branches. There was a uniform tumor blush. The right posterior inferior cerebellar artery (PICA), which arose along the ventral margin of the mass and coursed along its right lateral superior aspect, contributed

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(A) (Axial) and (B) (Coronal) Gadolinium enhanced T1WI demonstrates a homogeneously enhancing petrotentorial extra-axial mass that abuts the junction of the transverse and sigmoid sinuses. The two tumors are noncontiguous.

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only tiny branches. The right vertebral artery narrowed at and beyond the right PICA, likely because of tumor compression, and did not substantially contribute to the basilar artery circulation (Figure 3). The petro-tentorial tumor did not have a prominent tumor blush. INTERVENTION The patient was felt most likely to have two separate meningiomas of the right posterior fossa. Because the foramen magnum lesion was not present/ visible 2 years before, consideration was also given to the possibility of a metastatic tumor of unknown primary. She was brought to the operating room and positioned in the left lateral decubitus position. Cranial nerves 7, 8, 11, and 12 were continuously monitored throughout the operation. A right suboccipital craniotomy and far lateral exposure of C1 and C2 was performed. A right C1 laminectomy was fashioned to include the foramen transversarium, and the foramen magnum osteotomy extended to

the occipital condyle. The dura was opened just medial to the C2 nerve root sleeve and the right vertebral artery entry point, and extended up to the transverse-sigmoid sinus junction. We elected not to fully mobilize the right vertebral artery medially. A soft, vascular tumor filling the ventral foramen magnum was removed in a piece-meal fashion. The tumor did not appear to have a dural attachment. At the interface with the inferior cerebellum, the calcified portion of the tumor was encountered and resected. A small amount of tumor intimately involved the rootlets of the 9th through 12th cranial nerves and was not removed. Similarly, a small remnant of tumor was left adherent to the brain stem inferior to the foramen of Luschka to avoid violating the pia of the lateral medulla. Subsequently, the petro-tentorial lesion was removed. This tumor, with a broad-based dural attachment to the petrotentorial junction anterior to the junction of the transverse and sigmoid sinuses, had a firmer architecture and similar vascularity to the foramen mag-

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keratin (CAM5.2) and focal, but definite staining for glial fibrillary acidic protein (GFAP), supporting the diagnosis of CPP. The petro-tentorial tumor had features of a transitional and fibrous meningioma with prominent spindling of cells, abundant intercellular collagen and presence of scattered psammomatous calcifications. POSTOPERATIVE COURSE Because of increased dysphagia and gait unsteadiness, the patient spent 3 weeks in the inpatient rehabilitation unit, with continuous and steady improvement. Because of a near complete right vocal cord paralysis, she underwent a local fat injection into the right vocal cord to aid in medialization, which greatly improved her voice quality. Upon discharge, she was eating a mechanical soft diet and was given an outpatient physical therapy program. A 3 month follow-up MRI shows gross total resection of the petro-tentorial meningioma, while there is a small area of residual enhancement in the medulla at the site of the known residual.

Discussion

Right vertebral injection demonstrating the foramen magnum lesion. Arterial contribution arises from right-sided meningeal branches and small branches from the right PICA. The AICA does not appear to perfuse the lesion. Of note, the right petro-tentorial lesion is not visualized.

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num lesion. The tumor was removed in toto and the dural base was extensively coagulated. PATHOLOGY At time of intraoperative consultation, the distinct papillary architecture of the foramen magnum lesion raised a complex differential diagnosis including CPP, papillary meningioma, papillary ependymoma as well as the less likely possibility of a metastatic epithelial lesion with papillary features. On permanent sections, the histologic features were characteristic of CPP (Figure 4A, B). The tumor was composed of complex papillary fronds, lined by bland cuboidal cells with abundant eosinophilic pale cytoplasm. Focally, oncocytic changes as typically seen in CPP were observed. Microcalcifications were scattered throughout the lesion. Mitoses and/or necrosis were not seen. Immunohistochemical stains confirmed strong and diffuse staining for low molecular weight cyto-

This is an unusual case because of the simultaneous presence of an entirely extraventricular CPP and a petro-tentorial meningioma. The preoperative differential diagnosis of the foramen magnum tumor included: meningioma, by far the most common; hemangioblastoma; exophytic brain stem glioma; schwannoma; ependymoma; and much less likely, the possibility of choroid plexus papilloma or metastasis. The diagnosis of extraventricular CPP came as a surprise. Choroid plexus papillomas in adults mainly arise either in the fourth ventricle or its lateral recesses, while in children the tumors usually occur within the lateral ventricles, most commonly in the atrium [2]. Primary extraventricular development of CPP is rare. When present, the most frequent extraventricular location is the CPA [15], though other locations have been reported as well [1,6,12,15]. There are several hypotheses for extraventricular CPP. According to Azzman et al [1] ectopic CPP arises subsequent to primary or secondary ectopia. Primary ectopia is the presence of primitive ectopic secretory choroid plexus within the brain substance. Secondary ectopia is the segregation of choroidal tissue during the developmental stage of the brain. It is also suggested that extraventricular CPP may develop from the normal choroid tuft outside the foramen of Luschka [9,20], called Bochdalek’s flower basket (von Lang J as quoted in [20]).

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Foramen magnum tumor: the characteristic papillary architecture of CPP is observed in low power (A); papillary fronds are lined by bland cuboidal cells with abundant eosinophilic pale cytoplasm (B). There is evidence of focal oncocytic changes, a feature typical of CPP. Dark stromal calcifications are present and hematoxylin-eosin stained paraffin sections.

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Hydrocephalus is the most common mode of presentation of CPP secondary to obstruction and/or CSF overproduction [5,14]. This patient had no imaging evidence of hydrocephalus, and her symptoms were accountable by the mass effect at the foramen magnum. Angiographically, the choroid tuft outside the foramen of Luschka is usually perfused by the anterior-inferior cerebellar artery [8] and an enlarged AICA with dilated branches is suggestive of CPP in CPA tumors [21]. There was no dilatation of AICA on the angiogram suggesting a CPP, and continuity with the choroid in the foramen of Luschka was difficult to ascertain. Consideration for the petro-tentorial lesion was primarily meningioma. Based upon clinical and imaging findings, the impression was that the patient probably harbored two meningiomas. Incidences as high as 20% have been reported for independent and spatially separate multiple meningiomas [18]. Irradiation exposure [11,16,17] and chromosomal abnormalities [3,7,11,16,18] are established risk factors for meningiomas. Along with vestibular schwannomas, schwannomas in other locations and gliomas, the incidence of meningiomas is also increased in patients with Neurofibromatosis 2 (NF2) [7]. Mutations of the NF2 gene (chromosome 22) play

an important role in the formation of meningiomas through loss of the tumor suppressor gene product merlin (schwannomin) [16]. This remains the case even if the patient has no diagnostic criteria for NF2 and lacks a germ line mutation allelic to NF2. In one study, 83% of patients with multiple meningiomas were demonstrated to have NF2 mutations without concomitant germ line mutations [18]. After 22q loss, the second most frequently reported genetic abnormalities in meningiomas are deletions of 1p and 14q [3]. These deletions have been associated with higher tumor grade and more aggressive tumor progression [3,16]. Prior cranial irradiation and genetic predisposition because of neurofibromatosis or tuberous sclerosis are also proposed risk factors for multiple brain tumors of different types [4]. Our patient had no history of cranial irradiation and lacked stigmata of any of the phakomatoses. There are two previously reported cases of coincident CPP and meningioma [13,19]. Unlike the prior two reports, in our patient, both tumors were extraventricular. There is also a report of germinoma and CPP coexisting in the fourth ventricle, and the authors propose that the CPP acted as a non-specific activator of aberrantly located germ cells [10]. The two tumors in our case were not in

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continuity, and their simultaneous occurrence appears coincidental.

ramen magnum choroid plexus papilloma with drop metastases to the lumbar spine. AJNR 1991;12:564 –5. Fontaine B, Rouleau GA, Seizinger BR, et al. Molecular genetics of neurofibromatosis 2 and related tumors (acoustic neuroma and meningioma). Ann NY Acad Sci 1991;615:338 –43. Fujii K, Lenkey C, Rhoton AL. Microsurgical anatomy of the choroidal arteries. Fourth ventricle and cerebellopontine angles. J Neurosurg 1980;52:504 –24. Garcia-Valtuille R, Abascal F, Garcia-Valtuille A, et al. Adult choroid plexus papilloma of the posterior fossa mimicking a hemangioblastoma. J Neurosurg 2000;92: 870 –2. Israel Z, Lossos A, Ashkenazi E, Soffer D, Umansky F. Germinoma and choroid plexus papilloma coexisting in the fourth ventricle. Acta Neurochir 1996;138: 1252–3. Joachim T, Ram Z, Rappaport ZH, et al. Comparative analysis of the NF2, TP53, PTEN, KRAS, NRAS and HRAS genes in sporadic and radiation-induced human meningiomas. Int J Cancer 2001;94:218 –21. Kimura M, Takayasu M, Suzuki Y, et al. Primary choroid plexus papilloma located in the suprasellar region: case report. Neurosurgery 1992;31:563–6. Kodet R. [Multiple malformations of the central nervous system, choroid plexus papilloma and intraventricular meningioma.]. Ceskoslovenska Patologie 1983;19:55–61 (Czech) (abstr). Leblanc R, Bekhor S, Melanson D, Carpenter S. Diffuse craniospinal seeding from a benign fourth ventricle choroid plexus papilloma. J Neurosurg 1998;88:757– 60. Nomura H, Momma F, Furuichi S, Okamoto J. Primary choroid plexus papilloma of the foramen magnum. Neurol Med Chir 1995;37:685–7. Shoshan Y, Chernova O, Jeun SS, et al. Radiationinduced meningioma: a distinct molecular genetic pattern? J Neuropathol Exp Neurol 2000;59:614 –20. Soffer D, Pittaluga S, Feiner M, Beller AJ. Intracranial meningiomas following low-dose irradiation to the head. J Neurosurg 1983;59:1048 –53. Stangl AP, Wellenreuther R, Lenartz D, et al. Clonality of multiple meningiomas. J Neurosurg 1997;86:853–8. Takahashi J, Makita Y, Nabeshima S, Taikyoku T, Keyaki A, Nioka H. [A case of coincidental tumors of choroid plexus papilloma in the 4th ventricle and convexity meningioma.]. Nippon Gek Hokan-Archiv fur Japanische Chirurgie 1988;57:172–6 (Jpn) (abstr). Van Swieten JC, Thomeer RTWM, Vielvoye GJ, Bots GTAM. Choroid plexus papilloma in the posterior fossa. Surg Neurol 1987;28:129 –34. Zhang W. Choroid plexus papilloma of the cerebellopontine angle, with special reference to vertebral angiographic study. Surg Neurol 1982;18:367–71.

Conclusion There is no genetic link between these two tumors and their coexistence appears completely coincidental. The presence of coincidental meningioma and CPP is extremely rare. Fortunately, both tumors were on the right side and could be surgically removed with a single surgical approach. Because of extensive involvement of the lower cranial nerves and adherence to the pia of the medulla, a small remnant of CPP was left attached to these structures to avoid inducing new neurologic deficit. If the tiny tumor remnant seen on 3 month follow-up MRI scanning shows signs of subsequent growth on serial imaging, then radiotherapy or radiosurgery will be employed. A CPP exophytic from the 4th ventricle, occupying the CPA and foramen magnum, is very rare but must be considered in the differential diagnosis of a tumor in this location.

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14. The authors thank Lynn Root, RN, for editorial and patient care assistance. 15.

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