Case Review
Volume 4, No.2
October 2000
 Mostafa Fadli
 Najia El Abbadi
 Fouad Bellakhdar
 Department of Neurosurgery  Ibn Sina of the University
 Mohamed V
 Rabat
 Morocco
 Correspondence:
 Dr. Mostafa Fadli
 Service de Neurochirurgie
 Ibn Sina
 BP 8056 Rabat Nations Unies
 Rabat
 Morocco
 Fax: (212) 7 674 758
  Meningioma of the Anterior Part of the Third Ventricle in a Child - Case Report

   ABSTACT
Paediatric meningiomas are rare and those located in the third ventricle are extremely uncommon. A case of an anterior third ventricle meningioma in an 11-year-old boy is presented. Total resection of this tumour was accomplished through a right transfrontal transventricular approach. The literature is reviewed.

Keywords: Meningioma, paediatric neurosurgery, third ventricle and transfrontal transventricular approach.
   INTRODUCTION
Meningiomas of the child are rare, their incidence is estimated at 0.85% to 2.5% of all primary tumours in this age group.(7,16,20,21) Paediatric intraventricular localisation is unusual; there have been only 16 reported cases in the literature.(1,4,9,13,14) We describe an additional third ventricular meningioma.

   CASE REPORT
An 11-year-old, right handed Moroccan boy, known asthmatic since four months of age. His psychomotor development had been normal. One year before his hospitalisation the child experienced episodical visual obscuration and visual acuity reduction. Two months prior to admission the patient also experienced vomiting and bifrontal headaches.

Apart from papilloedema, the neurological examination was perfectly normal. Computed tomography (CT) scan with contrast showed hyperdense mass in the anterior part of the third ventricle with calcifications and associated hydrocephalus (Fig. 1).
Magnetic resonance images (MRI) confirmed the anterior intra-ventricular localisation. T1- and T2-weighted images showed isointensity mass (Fig. 2a and b). The MR angio did not show vascularisation of the tumour. The hydrocephalus was treated by right ventriculoperitoneal shunt. Post-operatively, his headaches improved and CT scan confirmed the successful reduction in ventricular size. Transfrontal transventricular approach via a right frontal craniotomy was made. The tumour was exposed anterior to the foramen of Monro by opening the thin ependymal lining along the medial floor of the frontal horn of the right lateral ventricle. The tumour was found to be adherent to the choroid plexus at the anterio inferior portion of the third ventricle. The vascular pedicle was then coagulated and separated from the choroid plexus. Using the ultrasonic aspirator and microtechniques, the tumour was totally removed. A pathological examination showed a tumour proliferation of regular meningothelial cells, some round pseudo epithelial and some lengthened spindle-shaped cells grouped in fascicles or lobules. These cells are rolled up in whorls joining calcified lamellaes (Fig. 3).
  2      
Figure 1 — CT scan: Anterior-part tumour of the third ventricle strongly enhanced on intravenous contrast infusion with calcification and hydrocephalus.   Figure 2a and b — Coronal T1-weighted and axial T2-weighted magnetic resonance without gadolinium: isointense third ventricle mass and hydrocephalus.

The post-operative course was uneventful and he was discharged on the eighth post-operative day. The CT scan performed one month after resection demonstrated total resection of the mass and hydrocephalus regression (Fig. 4).

     
  Figure 3 - Control MRI on sagittal T1-weighted image showing removal of the disc herniation and spinal cord decompression   Figure 4 - Sagittal T2-weighted image revealing a herniated disc at T11-T12 level, in addition to a high intramedullary signal corresponding to spinal injury.  

.
   DISCUSSION
Meningioma accounts for 10-15% of all intracranial tumours.(6) In the paediatric population these tumours are rare, constituting 0.85% to 2.5% of intracranial tumours.(7,16,20) Intraventricular localisation is uncommon, only 2-3% arise in the ventricle.(13,15,16,17,22) These intraventricular meningiomas are usually located in one of the lateral ventricles and rarely present as an isolated third ventricular mass.(14) The third ventricle is an exceptional site for meningiomas and accounts for 15% of intraventricular meningiomas.(5) In children it is an unusual site. Only 16 reported cases are known.(1,4,9,13,14)

In majority of cases they are located at the posterior part of the ventricle and exceptionally we find them in the anterosuperior part.(11) These tumours may develop at the expense of the arachnoid cells at tela choroidea on the free edge of which it usually fits. These tumours are regarded as benign, single, and well demarcated.

Third ventricular meningiomas can be anatomically divided into anterior and posterior locations. The anterior third meningiomas are thought to arise from arachnoidal tissue of the velum interpositum, tela choroidea, or choroid plexus.(6,12) Posterior third ventricular meningiomas are also thought to arise from the velum interpositum, tela choroidea, or choroid plexus. They can originate from structures outside the third ventricle, such as the falx, tentorial junctions or the connective tissue stroma of the pineal gland.(2,3) The fibroblastic type are predominant in the paediatric anterior third ventricular meningiomas, followed by meningotheliomatous and psammoumatous type.(18) The mixed type is rare.(16) These third ventricular mass usually present with increased intracranial pressure and hydrocephalus. Posterior third ventricular meningiomas frequently present as pineal tumours with cerebellar dysfunction and Perinaud’s syndrome.(19,20)

The clinical evolution is long, with loss of memory, endocrine disturbances, visual deterioration, giddiness and weakness of lower limbs.(18) The time lapse between the first symptom and the diagnosis is on average 36 months.(11)

Patients with anteriorly located third ventricular mass can have symptoms of transient hydrocephalus because of intermittent obstruction of the foramen of Monro.(14) In the radiological findings, meningiomas are typically hyperdense lesions imaged on CT. MRI of meningiomas usually demonstrates the lesion to be hypointense to isointense on T1-weighted images and isointense to hyperintense on T2-weighted sequences.(8) Typically, these neoplasms brightly enhance with contrast infusion on CT scan or MRI.(12) However, these modalities may not always be reliable in the tissue diagnosis. The differential diagnosis for this solid anterior third ventricular tumour include meningioma, craniopharyngioma, astrocytoma and germinoma. Each of these tumours can exhibit similar radiographic images in their intraventricular localisation.(10)

The approach to the third ventricle may be from a variety of angles because of its central location. The choice of operative approach is usually dictated by the location and extent of the tumour, as well as the surgeon’s experience and has recently been greatly improved with the aid of microsurgical techniques.

Surgical approaches include subfrontal translamina terminalis access, bifrontal anterior interhemispheric exposure, pterional craniotomy, transcortical-transventricular approach and anterior transcallosal exposure. Although the third ventricle can be entered by opening the lamina terminalis, via subfrontal craniotomy or biparietal inter-hemispheric dissection, these procedures were not selected because of their disadvantages, including exposure of the frontal sinus, extensive frontal lobe retraction and risk of olfactory bulb disruption.(18)

A frontal transcortical transventricular approach to lesions of the anterior third ventricle is most easily performed in patients with enlarged lateral ventricles. Transcallosal entry involves an inter-hemispheric approach down to the corpus callosum. An anterior midline callosal incision limited to 2 to 3 cm minimises the potential for “disconnection syndrome”. From the lateral ventricle there are varieties of approaches to the third ventricle. The operation can be performed transforaminally through a dilated foramen of Monro. However, the mid and posterior portions of the third ventricle are inaccessible.

Sectioning of the ipsilateral fornix provides access to the mid-anterior chamber but may cause significant memory impairment.(18) The subchoroidal approach extends to the foramen of Monro posteriorly. This involves ligation of the thalamostriate vein and separation of the choroid plexus behind the foramen from its thalamic attachment.(18) The transcortical approach offers better lines of visualisation into the third ventricle, although access to the deeper recesses is limited. In our patient, the meningioma was totally removed through a right transfrontal transventricular approach using micro-techniques and ultrasonic aspirator. We use this approach for tumours of the anterior part of the third ventricle because of its good exposure and better tolerance by the patients. Permanent insertion of a shunt before surgical resection may not be ideal as it may limit surgical options for exposure and increase the risk of infection. In an emergency situation, as in our patient when visual acuity is compromised, we prefer to carry out ventriculoperitoneal shunt and remove the tumour at a later stage.
   CONCLUSION
Third ventricular meningiomas in the paediatric population are rare. Surgical resection of these benign tumours can be performed with low morbidity using microsurgical techniques.

   REFERENCES
1. Abbot KH, Courville CB: Intraventricular meningiomas: Review of the literature and report of two cases. Bull Los Angeles Neurol Soc 1942, 7: 12-28
2. Ameli NO, Armin K, Saleh H: Incisural meningiomas of the falcotentorial junction: A report of two cases. J Neurosurg 1966, 24: 1027-1030
3. Araki C, Kyoto MD: Meningioma in pineal region: Report of two cases removed by operation. Nippon Geta Hoken 1937, 14: 1181-1192
4. Byard RW, Bourne AJ, Clark, Hanieh A: Clinico-pathological and radiological features of two cases of intraventricular meningioma in childhood. Ped Neuro-Sci 1989, 15: 260-264
5. Criscuolo GR, Symon L: Intraventricular meningioma. A review of 10 cases of the National Hospital, Queen Square (1974-1985) with reference of the literature. Acta Neurochir (Wien) 1986, 83: 83-91
6. Cushing H, Eisenhardt L: Meningiomas: Their classification, Regional Behavior, Life History and Surgical End Results. Hafner Publishing, New York 1969, p69
7. Deen HG, Scheithauer BW, Ebersold MJ: Clinical and pathological study of meningiomas of the first two decades of the life. J Neurosurg 1982, 56: 317-322
8. Hirsch WL, Roppolo HMN, Hayman LA, Hinck VC: Sella and parasellar regions: Pathology “MR and CT imaging of the head, neck and spine”, Latchow RE (Ed. St. Louis CV), Mosby Year Book 1991, 683-747
9. Huang PP, Doyle WK, Abbot IR: A typical meningioma of the third ventricle in a 6-year-old boy. Neurosurg 1993, 33(2): 312-316
10. Ikesaki K, Fuji K, Kishikawa T: Magnetic resonance imaging of an intraventricular craniopharyngioma. Neuro Radiol 1990, 32: 247-249
11. Jan M, Velut S: Meningiomes intracraniens, sarcomes meninges, melanomes meninges primitifs: Editions Techniques. Encycl-Med-Chir (Paris France). Neurologie 17251 A10, 1991, p21
12. Kobayashi S, Okazaki H, MacCarthy CS: Intraventri-cular meningiomas. Mayo Clin Proc 1971, 46: 735-741
13. Lee Y, Lin S, Horner FA: Third ventricle meningioma mimicking a colloid cyst in a child. AJR 1979, 132: 669-671
14. Markwalder TM, Seiler RW, Markwalder RV, Huber P, Markwalder HM: Meningioma of the anterior part of the third ventricle in a child. Surg Neurol 1979, 12: 29-32
15 Markwalder TM, Markwalder RV, Markwalder HM: Meningioma of the anterior part of the third ventricle. J Neurosurg 1979, 50: 233-235
16. Mendiratta SS, Rosenblum JA, Strobos RJ: Congenital meningioma. Neurol 1967, 17: 914-918
17. Olivecrona H: The parasagittal meningiomas. J Neurosurg 1947, 4: 327-341
18. Renfo M, Delashaw JB, Peters K, Rhoton E: Anterior third ventricle meningioma in an adolescent: A Case report. Neurosurg 1992, 31(4): 746-750
19. Roberts B, Frederick AH, McDonald JV: Anterior third ventricle meningioma in a child. Child's Brain 1981, 8: 145-148
20. Rubenstein LJ: Tumours of the Central Nervous System. Washington, Armed Forces Institute of Pathol 1972, pp169-190
21. Sheikh BY, Siqueira E, Dayel F: Meningioma in children: A report of nine cases and review of the literature. Surg Neurol 1996, 45: 328-335
22. Simpson D: The recurrence of intracanial meningioma after surgical treatment. J Neurol Neurosurg Psych 1957, 20: 22-39
 


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