The majority of subependymomas (n = 22) were isointense on T1, hyperintense (n = 22) on T2, and enhanced (n = 24). All tumors were located just below the body of the fourth ventricle, terminating near the level of the obex. Fourteen cases demonstrated the extension of the tumor into the foramen of Magendie or Luschka.
This is the largest collection of 4th ventricular subependymomas with imaging findings reported to date. All patients in this cohort had tumors originating between the bottom of the body of the 4th ventricle and the obex. This uniform and specific site of origin aids with imaging diagnosis and may infer possible theories of origin 1).
Fluorescence-guided resection with 5-ALA may be useful for resection of subependymomas of the fourth ventricle. However, further studies are needed 2).
A 44-year-old female with a large infratentorial mass which compressed the brain stem and fourth ventricle. Complete surgical excision of the tumor was achieved. The tumor composed of collections of cytologically bland cells with round to oval nuclei set within wide expanses of a delicate fibrillar matrix, and extensive microcystic changes were found. The tumor demonstrated positive staining with GFAP and S-100 protein, and did not stain with antibodies to Neu-N or Progesterone receptor, patchy expression of Epithelial Membrane Antigen. An MIB-1 labeling was lower than 1%. The tumor was totally resected and didn't recur after the initial surgery 3).
A rare case of subependymoma of the fourth ventricle in identical female twins is reported. Magnetic resonance imaging and CT showed nearly identical locations of the tumors in the fourth ventricle and similar growth patterns of the tumors in both sisters 4).
A 33-year-old man was admitted with 5 days history of oppressive occipital headache and neck pain without additional neurological focus. Unenhanced computed tomography (CT) scan demonstrated an isointense mass located in the fourth ventricle with a spontaneously hyperdense acute extratumoral hemorrhage in the cisterna magna. Contrast-enhanced magnetic resonance imaging (MRI) revealed a well-delimitated non-enhanced tumor, hypointense on T1-weighted and hyperintense on T2-weighted images, involving the floor of the fourth ventricle and extending caudally into the cervical spinal canal via foramen magnum.
Intraoperative, a large blood clot was removed and a macroscopically hypovascularlesion was completely excised from the right lateral recess and the floor of the fourth ventricle. Intra and postoperative immuno-histopathological examination revealed a SE. The patient has a normal postoperative course and was discharged in the fifth postoperative day. A 10-month postoperative MRI study confirmed a complete tumor resection.
Symptomatic SEs should be surgically treated emphasizing the urgency in the presence of hemorrhage. The interest of this case is to demonstrate that infratentorial SEs although extremely rare, might present with acute subarachnoid bleeding 5).
Hemifacial spasm (HFS) as the presenting symptom Based on the intraoperative data and on the previously reported cases, we think that pathogenesis could be referable to the facial nerve nucleus involvement and that clinical nuances could be related to the specific somatotropy of the nucleus under the fourth ventricle floor that, as in our case, can be infiltrated by tumour. Resolution of the disorder can usually be obtained after the complete resection of the tumour that in the reported case resulted a subependymoma (WHO grade I), so far never described in literature associated with HFS 6)