Of the intraventricular meningiomas, only 6% are primarily in the fourth ventricle. ¹⁾.

The most common age of onset was from the third decade to sixth decade of life. The female/male ratio was about 1.16:1. The most frequent subtype of meningioma was fibrous meningioma ²⁾.

The FVMs had specific imaging features, such as calcification (20%), peritumoral edema (30.3%), heterogeneous enhancement (22.5%), cystic formation (4.3%) and hydrocephalus (52.8%) ³⁾.

The computed tomography (CT; n=5), magnetic resonance imaging (MRI; n=9) features and clinical presentations of 10 patients with pathologically documented fourth-ventricular meningiomas were retrospectively analysed.

All tumours appeared as well-demarcated masses in the fourth ventricle at CT and MRI. The tumour shape was round in eight cases (80%) and irregular in two cases (20%). The CT images of five cases showed predominantly isoattenuation in three cases and high attenuation in two cases, with a mean attenuation value of 52 HU. In addition, calcifications were seen in three cases. At MRI, nine masses were isointense (n=6) or hypointense (n=3) to grey matter on T1-weighted images and mildly hyperintense (n=4), isointense (n=3), hypointense (n=1), and of mixed signal intensity (n=1) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Signal voids were visible in two cases. Enhancement after injection of contrast material was marked homogeneous (n=5) or heterogeneous (n=5) on CT or T1-weighted images. Three tumours had mild peritumoural oedema. Three tumours were associated with obstructive hydrocephalus. The pathological subtype of the 10 meningiomas was fibromatous (n=5), atypical (n=2), and one each of transitional, psammomatous, and clear-cell type.

The relatively typical radiological appearance, combined the age and sex of patients, can suggest the diagnosis of fourth-ventricular meningioma ⁴⁾.

The recommended treatment is surgical treatment via the telovelar approach with suboccipital craniotomy/craniectomy. Adjuvant therapy is needed in some of the high grade meningiomas and in cases underwent partial resection ⁵⁾.

The prognosis is relatively good, with less postoperative complications and higher rate of total resection ⁶⁾.

In the series of Luo et al., the proportion of total tumor resection was about 94.9%, with 15.3% of postoperative complications. During follow-up, the recurrent rate of FVMs was about 6.8%. There was no significant difference in the analysis of correlation between hydrocephalus and the maximum diameter of tumors, correlation between hydrocephalus and the volume of tumor, correlation between peritumoral edema and the volume of tumor, as well as correlation between heterogeneous enhancement and the grade of meningiomas ⁷⁾.

Luo et al., published a series of eleven Fourth ventricular meningioma at one single institution. A comprehensive literature analysis was conducted.

The information of eleven cases were extracted from the patient data. And English cases were obtained from the literature. Including the 11 cases, 71 cases were analyzed in this study. ⁸⁾.

Sadashiva et al., published two cases harboring a primary fourth ventricular meningioma Grade II, which was surgically excised successfully. Total excision was achieved in both cases and as the tumor was firm to soft and vermian splitting was not required. Understanding the clinical features and a careful preoperative radiological examination is required to differentiate this tumor from more commonly occurring lesions at this location ⁹⁾.

Zhang et al., presented the neuroradiological and clinical findings of fourth-ventricular meningiomas to increase awareness of this entity.

The computed tomography (CT; n=5), magnetic resonance imaging (MRI; n=9) features and clinical presentations of 10 patients with pathologically documented fourth-ventricular meningiomas were retrospectively analysed.

All tumours appeared as well-demarcated masses in the fourth ventricle at CT and MRI. The tumour shape was round in eight cases (80%) and irregular in two cases (20%). The CT images of five cases showed predominantly isoattenuation in three cases and high attenuation in two cases, with a mean attenuation value of 52 HU. In addition, calcifications were seen in three cases. At MRI, nine masses were isointense (n=6) or hypointense (n=3) to grey matter on T1-weighted images and mildly hyperintense (n=4), isointense (n=3), hypointense (n=1), and of mixed signal intensity (n=1) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Signal voids were visible in two cases. Enhancement after injection of contrast material was marked homogeneous (n=5) or heterogeneous (n=5) on CT or T1-weighted images. Three tumours had mild peritumoural oedema. Three tumours were associated with obstructive hydrocephalus. The pathological subtype of the 10 meningiomas was fibromatous (n=5), atypical (n=2), and one each of transitional, psammomatous, and clear-cell type.

Although fourth-ventricular meningioma is quite rare, it should be considered in differential diagnosis of neoplasms within the fourth ventricle. The relatively typical radiological appearance, combined the age and sex of patients, can suggest the diagnosis of fourth-ventricular meningioma ¹⁰⁾.

A adult patient with a rare chordoid meningioma located within the fourth ventricle. This lesion was treated with gross total resection. Chordoid meningioma must be considered within the differential diagnosis of intraventricular tumors. This histological subtype of meningioma warrants close follow-up. The patient must also be evaluated for systemic manifestations of Castleman’s disease ¹¹⁾.

A 14-year-old man with seizure and headache. The magnetic resonance imaging reported bilateral acoustic neuroma and fourth ventricle meningioma. The patient was scheduled for total tumor resection and the histopathology revealed psammomatous type of meningioma. The patient discharged with good general status ¹²⁾.

A 60-year-old man was admitted with slowly progressive dizziness. Cranial nerve evaluation found no abnormalities. Magnetic resonance imaging revealed a well-circumscribed mass with homogeneous enhancement located in the fourth ventricle. The patient underwent surgery for the removal of the tumor via the bilateral suboccipital approach. Subtotal removal of the tumor was achieved in a piecemeal fashion. Histological diagnosis was meningothelial meningioma ¹³⁾.

A 25-year-old man with fourth ventricular meningioma. Qin et al., refer to the usefulness of diffusion-weighted imaging and apparent diffusion coefficient measurements for the differential diagnosis of fourth ventricular tumors ¹⁴⁾.

A fourth ventricular clear cell meningioma without dural attachment in a 14-year-old boy with an unusual presentation of failure to thrive ¹⁵⁾.

Lyngdoh et al., published in 2007 two cases ¹⁶⁾.

Liu et al., published one case in a series of intraventricular meningiomas ¹⁷⁾.

A 76 year old male patient presenting with a 2-week history of headache and cognitive disorders with agitation and restlessness particularly exacerbated at night or when lying down. CT scan and MR imaging showed a contrast-enhancing lesion located purely within the whole fourth ventricle, with slight ventricular enlargement. At surgery, we totally removed a well-vascularised, greyish encapsulated mass attached to the choroid plexus. Pathological examination revealed a WHO grade I fibroblastic meningioma ¹⁸⁾.

A 72-year-old female presented with an intra-fourth ventricular meningioma manifesting as truncal ataxia. Computed tomography (CT) showed a slightly high-density, well-demarcated, and homogeneously enhanced mass located in the fourth ventricle and extending to the right lateral recess. T2-weighted magnetic resonance (MR) imaging revealed a peritumoral high-intensity band without dural tail sign. Bilateral vertebral angiography revealed faint tumor staining supplied from the choroidal branches of the posterior inferior cerebellar arteries. The mass was totally resected via a suboccipital approach. CT, T2-weighted MR imaging, and vertebral angiography are informative for the preoperative diagnosis of fourth ventricular meningioma ¹⁹⁾.

A 72-year-old man operated upon for such a tumor. The pre-operative magnetic resonance images revealed a well circumscribed mass in the fourth ventricle that exhibited a low signal on T1-weighted magnetic resonance images and homogenously enhanced with gadolinium. By light microscopy the tumor was composed of tightly packed spindle cells separated by collagen. Immunohistochemistry showed the tumor cells to be positive for vimentin and epithelial membrane antigen, and negative for glial fibrillary acidic protein. Electron microscopy revealed typical findings of meningioma, including interdigitating cell processes, desmosomes, and intermediate filaments. Although rare, fibroblastic meningioma must be included in the differential diagnosis of a fourth ventricular spindle cell tumor in elderly patients ²⁰⁾.

In 1992 a rare case of fourth ventricle meningioma with a combined intraventricular-intracerebellar localization, successfully removed by surgical treatment, is reported ²¹⁾.

Perry et al., reported two cases, one with typical CT, angiographic, and magnetic resonance (MR) appearances and one with atypical features of central cyst formation on CT and MR. The utility of MR in demonstrating intraventricular location in three imaging planes is illustrated. Given the rarity of these tumors, atypical features may preclude accurate preoperative diagnosis, even with MR ²²⁾

Rodriguez-Carbajal and Palacios published in 1974 2 cases ²³⁾.