Neurosurg Focus 20 (3):E9, 2006

Intraventricular meningiomas: a clinicopathological study and review of the literature

HARJINDER S. BHATOE, M.CH., PRAKASH SINGH, M.CH., AND VIBHA DUTTA, M.D., PH.D. Departments of Neurosurgery and Pathology, Army Hospital, Research and Referral, New Delhi, India

Object. Intraventricular meningiomas are rare tumors. The origin of these tumors can be traced to embryological invagination of arachnoid cells into the choroid plexus. The authors analyzed data that they had collected to study the clinicopathological aspects and review the origin, presentation, imaging, and management of these tumors. Methods. In this retrospective analysis, the authors describe the cases of 12 patients who had received a diagno- sis of intraventricular meningioma and underwent surgery for the tumors. Nine of these patients were men and three were women. Features of neurofibromatosis Type 2 were present in two of the women. Nine of the tumors were lo- cated in the lateral ventricles, one was in the third ventricle, and two were in the fourth ventricle. Raised intracra- nial pressure (ICP) was the universal presentation in all the patients, and the preoperative diagnoses were confirmed on neuroimaging studies. Excision was performed using the parietooccipital (trigonal) approach for lateral ventri- cle tumors, the transcortical–transventricular route for the third ventricle tumor, and suboccipital craniectomy for fourth ventricle tumors. Postoperatively, one patient died and the others experienced resolution of their symptoms. Histopathological features of these tumors were similar to those seen in meningiomas in other locations. Conclusions. Intraventricular meningiomas are slow-growing tumors that become large prior to detection. Al- though they are commonly seen in the lateral ventricles, they occur in the third and fourth ventricles as well. Pre- sentation is in the form of raised ICP with no localizing features; therefore the diagnosis is based on imaging stud- ies. Hydrocephalus occurs due to obstruction of cerebrospinal fluid pathways. Excision requires planning to avoid eloquent cortex incision. The histopathological features are varied, although most of the tumors in the study were angiomatous meningiomas. These tumors are no different histologically from tumors that are dural in origin. No re- currence has been reported.

KEY WORDS • brain tumor • third ventricle • fourth ventricle • lateral ventricle • choroid plexus • intraventricular tumor • meningioma

EREBRAL ventricles are unusual sites for the occur- Clinical Material and Methods rence of tumors in the central nervous system. The C incidence of tumors follows a regional preference, We retrospectively analyzed the records of 12 patients in with ependymomas and primitive neuroectodermal tumors whom intraventricular meningioma had been diagnosed. being seen more often in the fourth ventricle and colloid These patients underwent treatment during a period of 12 cysts in the third ventricle. Tumors that are most likely to years (1993–2005) in three different service hospitals. There occur in the lateral ventricles are astrocytomas, subependy- were three women and nine men; all were in their third and mal giant cell astrocytomas, and ependymomas. Intraven- fourth decades of life. Presentation, imaging features, surgi- tricular meningiomas are rare tumors, accounting for 0.5 to cal procedures performed, histological diagnoses, and post- 5% of all intracranial meningiomas.8 Although there are operative results were analyzed. Only those patients with series in which lateral ventricle meningiomas have been re- histologically proven meningiomas were included in the ported, there are only case reports of third and fourth ven- study. Whereas the symptoms in patients with lateral ven- tricle meningiomas. In this report, we present our experi- tricle meningiomas were insidious and protean, the preop- ence with 12 cases of intraventricular meningiomas. The erative course was shorter and more acute in those who had relevant literature is briefly reviewed. third and fourth ventricle tumors. One patient, who had a calcified intraventricular tumor, had experienced headaches for nearly 16 years prior to detection of the tumor. Head- Abbreviations used in this paper: CT = computerized tomogra- phy; ICP = intracranial pressure; MR = magnetic resonance; NF2 = ache, intermittent or persistent, was the most common neurofibromatosis Type 2; PICA = posterior inferior cerebellar symptom and was present in all patients. One of the three artery; VS = vestibular schwannoma. women had unilateral proptosis and sensorineural deafness

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Unauthenticated | Downloaded 09/26/21 12:09 AM UTC H. S. Bhatoe, P. Singh, and V. Dutta along with significant café-au-lait spots, and another wom- an presented only with sensorineural deafness and head- ache. Papilledema was observed in eight patients, and uni- lateral optic atrophy was seen in the woman who had proptosis in her eye. There were no other localizing signs. Images of all patients were obtained using skull radio- graphy and CT. Four patients also underwent MR imaging. As shown in Figs. 1 through 5, the distribution of tumors was as follows: nine in the lateral ventricle (seven in the left hemisphere and two in the right), one in the third ventricle (in the woman with NF2), and two in the fourth ventricle. Whereas one lateral ventricle tumor was solid and dense- ly calcified, another was partially cystic. Others were solid and were intensely enhanced after addition of intraven- ous contrast agents. The intraventricular tumors in the two women who had NF2 were caused by that condition, as were their multiple intracranial tumors. One of these wom- en had a third ventricle meningioma along with an optic nerve sheath meningioma, VS, and two small cerebral con- vexity meningiomas; the other woman had lateral ventricle meningioma and bilateral VSs. All patients underwent excision of the intraventricular tumors. Total excision was achieved in all.

Surgical Procedures Lateral Ventricle Tumors. All of the tumors were in the atrium (trigone) of the lateral ventricle. They were ap- FIG. 1. Axial CT scan revealing densely calcified lateral ventri- proached via a transcortical route, through an incision over cle meningioma. the parietooccipital cortex to open the ventricle. The cap- sule was extensively coagulated using bipolar current, and the tumor capsule was emptied in the area of coagulation so rhage, one patient had persistent postoperative homony- that it could be turned to expose its feeding vessels originat- mous hemianopia, and recovery was uneventful in seven. ing from the posterior choroidal artery. These vessels were Two patients had transient speech disturbances following then coagulated and divided, and the tumor was excised in surgery, which resolved within 4 weeks. In one of the two one piece. women who had NF2, a retromastoid craniectomy and ex- Third and Fourth Ventricle Tumors. The only third ventri- cision of VS was done prior to excision of the lateral ven- cle tumor was excised in one piece using a transcortical– tricle meningioma. transventricular route. One of the two fourth ventricle tu- mors had the PICA draped over it, and this was causing severe brainstem distortion in the patient. The artery was carefully mobilized and protected. The tumor was coagu- lated and hollowed out so that it could be dissected in the arachnoid plane and separated from the floor of the fourth ventricle. The tumor in the other patient received its vascu- lar supply from the choroid plexus on the left side of fourth ventricle. The tumor was coagulated and divided, then ex- cised piecemeal. In all patients, the dura mater was closed primarily or by duraplasty in which a pericranium or temporalis fascia graft was used.

Results Results were analyzed for immediate postoperative out- come and long-term follow up as well as to determine the histological variants of the tumor.

Lateral Ventricle Tumors Of nine patients with this type of tumor, one patient died in the postoperative period due to intraventricular hemor- FIG. 2. Axial CT scan revealing a lateral ventricle meningioma.

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FIG. 3. Three Gd-enhanced MR images revealing meningioma in the trigone of the lateral ventricle.

Third Ventricle Tumor excision of VS, and the optic nerve meningioma was re- In the one patient with this type of tumor (one of the two moved in a separate surgical procedure. women who had NF2) recovery was difficult due to a post- Fourth Ventricle Tumor operative cerebrospinal fluid leak and a case of meningitis that required a prolonged antibiotic regimen. After recov- One patient had postoperative respiratory dysfunction ery, the patient underwent a retromastoid craniectomy for and oropharyngeal paralysis, probably due to injury to the

FIG. 4. Preoperative CT scans demonstrating third ventricle meningioma as part of NF2 complex, with accompany- ing optic nerve sheath meningioma and VS.

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Discussion The presence of arachnoid cell nests in the normal choroid plexus stroma has been illustrated in the literature, and a thorough examination of the choroid plexus usually reveals small or sometimes larger collections of these cells.7,12,23 The presence of these cells in the choroid plexus has been explained by various investigators. The choroid plexus develops initially from an invagination of a mes- enchyme in the thin, roof area of the myelencephalon dur- ing the 6th week of gestation.26 In the 7th to 9th weeks, the telencephalic choroid plexus has started to develop a loose mesenchymal stroma, which is covered by a layer of cells derived from the ependyma.6 Arachnoid tissue is transport- ed together with the choroid plexus as the ventricular sys- tem invaginates,15 and by 20 to 40 weeks, the central stro- ma of the choroid plexus contains meningocytes, connective tissue, and blood vessels.23 Meningiomas arise from arachnoid cap cells, which are specialized cells in arachnoid granulations. In a similar fashion, intraventricu- lar meningiomas arise from arachnoid cells contained with- in the choroid plexus. Meningothelial inclusion bodies are normally found in the arachnoid and choroidal tela, and meningiomas arise from this mesenchymal stroma of the choroid plexus.18,21 Third ventricle tumors may arise from the tela of the velum interpositum, which is the space between the two layers of tela in the roof of the third ven- tricle that contains the posterior medial choroidal arteries 25 FIG. 5. Axial CT scan revealing a fourth ventricle meningioma. and internal cerebral veins. Fourth ventricle meningiomas characteristically arise from choroids or interior tela choroidea.10 floor of the fourth ventricle. The patient underwent venti- Ventricles are rare sites for the occurrence of meningio- lation therapy for 8 days, and was weaned thereafter. He mas. The incidence of meningiomas of lateral ventricles in required a nasogastric feeding tube, and remained depen- adults is variously reported as between 0.5 and 5% of all dent on it after discharge. Recovery was uneventful in the intracranial meningiomas.8,16 For unknown reasons, menin- other patient. giomas of the lateral ventricles occur more frequently on the left (up to 60% of all lateral ventricle meningiomas) than the Pathological Findings right.4,8,9 Because the choroid plexus is more bulky in the lat- Eleven of the tumors were sent to a pathology laborato- eral ventricles, incidence of lateral ventricle meningiomas is ry as fragmented tissues, and the other, a calcified intra- higher compared with those in the third or fourth ventricles. ventricular tumor that had been removed from a lateral ven- Meningiomas are rare in the third and fourth ventricles; in tricle, was sent as a single, rock-hard mass. The fragmented tumors were fixed in formalin and subjected to routine pro- cessing. In all cases, H & E–stained sections were used for final diagnosis. Reticulin stains were done in cases of an- giomatous meningioma to differentiate them from heman- giopericytoma. The rock-hard completely calcified tumor was cut into small pieces with an oscillating saw and fixed in formalin. Histopathological findings in the tumors were varied, as seen in Figs. 6 and 7. Of the lateral ventricle tumors, four were angiomatous, three were meningothelial, one was psammomatous/osteoblastic, and one was macrocys- tic angiomatous. The sole third ventricle tumor was angio- matous. Of the two fourth ventricle tumors, one was fibro- blastic and one was meningothelial. In nine of the patients, tests for epithelial membrane anti- gen and vimentin were positive. The psammomatous me- ningioma showed densely packed psammoma bodies in an ossified matrix. All 11 surviving patients were followed for 3 to 10 years, with no evidence of recurrence. The two patients FIG. 6. Photomicrograph showing histopathological findings in with NF2 had surgery for associated tumors. a fibroblastic meningioma. H & E, original magnification ϫ 10.

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ment, MR imaging is needed for diagnosis of the tumor. The MR images reveal the tumor to be hypo- or isointense

on T1-weighted images, and the tumor enhances densely and uniformly after the addition of gadolinium. The MR spectroscopy and blood volume–time intensity maps alone or together may increase the certainty of preoperative diag- nosis. A high alanine-to-creatinine ratio has been reported as a specific MR spectroscopic finding for meningiomas.17 Fibroblastic meningiomas, the most common type in the 19 lateral ventricles, are hypointense on T2-weighted images. Macrocystic tumors are rare, and have been reported only twice; 4 both of those tumors and the macrocystic tumor seen in our series were aggressive and malignant. Addition- al tumors such as those that occur in cases of NF2 are well delineated on MR images. Digital subtraction angiography can be used for assessment of vascularity and to determine FIG. 7. Photomicrograph showing histopathological findings in the location of the principal feeder vessel. an angiomatous meningioma. H & E, original magnification ϫ 40. Lateral ventricle tumors are fed by lateral–posterior cho- roidal vessels, whereas those in the temporal horn receive their blood supply from the anterior choroidal artery. Tu- our extensive review of the literature, we found reports of mors in the atrium are supplied by both anterior and poste- only 83 meningiomas in the third ventricle and 35 menin- 20 rior choroidal arteries. Third ventricle tumors are supplied giomas in the fourth. by medial posterior choroidal vessels, whereas fourth Ventricles of the brain provide space for tumor expan- ventricle tumors derive their blood supply from choroidal sion, and until the cerebrospinal fluid pathways are mechan- branches of the PICA.14 ically occluded, manifestations are mild and nonspecific. 5 Surgical management of intraventricular meningiomas Cushing and Eisenhardt described five clinical features requires careful planning. In cases of tumors involving the of lateral ventricle tumors: 1) pressure symptoms with ip- dominant lobe, preoperative neuropsychological testing silateral headache; 2) contralateral macula splitting homon- should be performed. Meningiomas are solid, discrete le- ymous hemianopia; 3) contralateral sensorimotor paresis, sions that can be totally excised. The strategy should be to more marked sensory involvement, and numbness over reach the blood supply with minimal brain resection, coag- trigeminal distribution; 4) cerebellar involvement in more ulation of the tumor prior to incision, internal decompres- than half of patients; and 5) paralexia, worsened by surgical sion, and occlusion of the feeding vessels. Magnification intervention in left-sided tumors. greatly aids in tumor excision. The optic radiation runs lat- Regardless of their locations, most of the clinical symp- eral and inferior to the atrium. Visual symptoms can be toms are due to increased IP. Lesions grow into the ven- caused by larger tumors in this tract or occur following re- tricular cavity until they produce obstructive hydro- section of these tumors through the temporal lobe. A ple- cephalus. Visual field deficits may be seen in 25% of thora of surgical approaches for meningiomas of the lateral patients,8 and seizures are rare.24 Cerebellar signs may be ventricle have been developed to address the risk to visual seen in fourth ventricle tumors, and hypothalamic features fields, the left-sided preponderance of the tumors with their with or without endocrinopathy may be seen in third ven- potential for speech and cognitive deficits, and the need for tricle tumors. Manifestations of NF2 may be evident on early control of the vascular pedicle. These approaches clinical and neurological evaluation. Although menin- may be made through the cerebral convexity (temporal, giomas are more common in women, in our 12-patient parietotemporal, and parietooccipital lobes), which would group only three were women who had intraventricular involve occipital lobectomy, or through the corpus cal- meningiomas; two of these women had features of NF2. losum.8 Most of these approaches lead to iatrogenic mor- Although intraventricular meningiomas are reported to be bidity in the form of visual field deficit, disconnection common in childhood,8,13 there were no children with these syndrome, or speech and cognitive deficits. The parietooc- tumors referred to our center. cipital approach follows a craniocaudal orientation parallel The rarity of intraventricular meningiomas in contrast to the optic radiation over the cerebral convexity and is to those with dural attachment may also be due to a yet un- least likely to damage the optic radiation. Moreover, this is known factor. Multiple meningiomas arising from the dura often the thinnest region overlying the trigone and the mater are regarded as being caused by the inherent multi- tumor. Debulking allows the tumor to be turned so that the centricity of the dural foci, possibly influenced by hormon- feeding choroidal vessel can be controlled effectively; early al factors.11 Although there are no reports of multiple intra- attempts at control may result in undesirable brain retrac- ventricular meningiomas, such tumors have been known to tion and its sequelae. Although early control of the feeding coexist with spinal meningiomas,22 VSs, and optic nerve vessel is desirable, that may not be possible until the tumor sheath meningiomas that may accompany NF2. is debulked and turned to expose the vessel. With this ap- Neuroimaging is usually necessary for diagnosis of these proach, a tumor can be completely excised, and speech and tumors. Intraventricular meningiomas may occasionally be cognitive deficits, if any, are mild and transient. A high cor- densely calcified so as to be visible on plain skull radio- tical incision can be made in the dominant hemisphere to graphs.2 Although CT scans may show calcification, avoid speech disturbances, and frameless stereotaxy can be obstructive hydrocephalus, and uniform contrast enhance- used to secure a safe trajectory.24 Small third ventricle tu-

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Unauthenticated | Downloaded 09/26/21 12:09 AM UTC H. S. Bhatoe, P. Singh, and V. Dutta mors can be reached via a transcortical–transforaminal ap- 6. Dohrmann GJ: The choroid plexus: a historical review. Brain proach, whereas large tumors may require transcallosal ex- Res 18:197–218, 1970 posure. To avoid hypothalamic injury, there should be no 7. Dunn J Jr, Kernohan JW: Histologic changes within the choroid traction on the tumor. Large tumors are poor candidates for plexus of the lateral ventricle: their relation to age. Mayo Clin excision due to the morbidity associated with neuroen- Proc 30:607–616, 1955 docrine, hypothalamic dysfunction and the possible deep 8. Erman T, Göcer AI, Erdogan E, et al: Intraventricular menin- giomas: a review and report of eight cases. Neurosurg Quar- venous system injury associated with surgery of large third terly 14:154–160, 2004 ventricle tumors. Fourth ventricle tumors are best ap- 9. Fornari M, Savoiardo M, Morrello G, et al: Meningiomas of the proached by suboccipital craniectomy, splitting of the ver- lateral ventricles. Neuroradiological and surgical considerations mis, and coagulation of surface vessels, while preserving in 18 cases. J Neurosurg 54:64–74, 1981 important vessels like the PICA. The tumor is internally 10. Guidetti B, Delfini R: Lateral and fourth ventricle meningiomas, decompressed so that it can be separated from the brain- in Al-Mefty O (ed): Meningiomas. New York: Raven Press, stem and excised totally. Hemostasis has to be meticulous 1991, pp 569–587 to prevent postoperative intraventricular hematoma. 11. Kamiya K, Inagawa T, Nagasako R: Malignant intraventricular Intraventricular meningiomas can be any of the histo- meningioma with spinal metastasis through the cerebrospinal pathological tumor types (predominantly fibrous, fibrob- fluid. Surg Neurol 32:213–218, 1989 lastic, meningothelial, or psammomatous) defined by the 12. Kepes JJ: The histopathology of meningiomas. A reflection of World Health Organization classification of meningiomas.8 origins and expected behaviour. J Neuropath Exp Neurol 45: 95–107, 1986 Angiomatous tumors were the most common type seen in 13. Kloc W, Imielinski BL, Wasilewski W, et al: Meningiomas of our series, followed by meningothelial, fibroblastic, and the lateral ventricles of the brain in children. Childs Nerv Syst psammomatous/osteoblastic types. The structure of psam- 14:350–353, 1998 moma bodies in the choroid plexus is very similar to that 14. Konovalov AN, Filatov YM, Belousowa OB: Intraventricular in meningiomas.1 In general, meningiomas are diagnosed meningiomas, in Schmidek HH (ed): Meningiomas and Their based on morphological features alone. The expression of Surgical Management. New York: WB Saunders, 1991, pp estrogen receptors is low in these tumors, and two thirds of 364–374 patients who have such tumors are positive for progester- 15. Ladenheim JC: Choroid plexus meningiomas of the lateral one receptors.3 It remains to be seen whether these findings, ventricle. Springfield, IL: Charles C Thomas, 1963 and cytogenetic features like deletion of chromosome 1 and 16. Lapras C, Deruty R, Bret PH: Tumors of the lateral ventricles. 14 that occur in meningiomas at other sites, can be ap- Adv Tech Stand Neurosurg 11:103–167, 1984 plicable to intraventricular meningiomas. 17. Majos C, Alonso J, Aguilera C, et al: Utility of proton MR spec- troscopy in the diagnosis of radiologically atypical intracranial meningiomas. Neuroradiology 45:129–136, 2003 18. Mani RL, Hedgcock MW, Mass SI, et al: Radiologic diagnosis Conclusions of meningioma of the lateral ventricle. Review of 22 cases. J Intraventricular meningiomas are rare tumors, occasion- Neurosurg 49:249–255, 1978 ally seen as part of the NF2 complex. Most authors have re- 19. McDermott MW: Intraventricular meningiomas. Neurosurg ported a preponderance of meningiomas in women. There Clin N Am 14:559–569, 2003 20. Nakamura M, Roser F, Bundschuh O, et al: Intraventricular are no unique clinical features on presentation, and raised meningiomas: a review of 16 cases with reference to the litera- IP is usually evident at that time. A diagnosis must be ture. Surg Neurol 59:491–504, 2003 established using MR imaging, and surgery requires plan- 21. Russell DS, Rubinstein LJ: Pathology of Tumors of the Cen- ning to avoid eloquent area damage. Early control of the tral Nervous System, ed 5. Baltimore: Williams & Wilkins, vascular supply to the tumor is critically important, and the 1989, p 449 tumor can usually be removed intact without damage to 22. Santoro A, Tacconi L, Paolini S, et al: Multiple meningiomas in vital areas around the ventricles. No recurrences have been different neuraxial compartments. Report of two cases. J Neu- reported after complete excision. The histology of these rosurg Sci 43:211–215, 1999 tumors is in no way different from that of meningiomas 23. Shuangshoti S, Netsky MG: Histogenesis of choroid plexus in with dural attachment. man. Am J Anat 118:283–316, 1966 24. Tew JM, Larson JJ Jr: Intraventricular meningiomas, in Kaye AH, Black PML (eds): Operative Neurosurgery. London: References Churchill Livingstone, 2000, pp 575–585 1. Alcolado JC, Moore IE, Weller RO: Calcification in the human 25. Tung H, Apuzzo MLJ: Meningiomas of the third ventricle, in choroid plexus, meningiomas and pineal gland. Neuropathol Al-Mefty O (ed): Meningiomas. New York: Raven Press 1991, Appl Neurobiol 12:235–250, 1986 pp 583–591 2. Bhatoe HS, Gill HS, Sreeram MN, et al: Densely calcified later- 26. Wannamaker GT: Intraventricular meningioma of the brain. J S al ventricular meningioma. Ind J Radiol Imaging 4:117–118, C Med Assoc 70:262–263, 1974 1994 3. Carroll RS, Glowacka D, Dashner K, et al: Progesterone receptor expression in meningiomas. Cancer Res 53:1312–1316, 1993 4. Criscuolo GR, Symon L: Intraventricular meningioma. A review of 10 cases of the National Hospital, Queen’s Square (1974– Manuscript received December 19, 2005. 1985) with reference to the literature. Acta Neurochir (Wien) Accepted in final form February 6, 2006. 83:83–91, 1986 Address reprint requests to: Harjinder S. Bhatoe, M.Ch., Depart- 5. Cushing H, Eisenhardt L: Meningiomas. Their Classification, ment of Neurosurgery, Army Hospital, Research and Referral, Regional Behavior, Life History and Surgical End Results. Delhi Cantt 110010, New Delhi, India. email: hsbhatoe@india Springfield, IL: Charles C Thomas, 1938, pp 139–149 times.com; [email protected].

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