Imaging Predictors of Intracranial Ependymomas

Surgical management and long-term outcome of intracranial subependymoma

BACKGROUND

Intracranial subependymomas account for 0.2-0.7% of central nervous system tumours and are classified as World Health Organization (WHO) grade 1 tumours. They are typically located within the ventricular system and are detected incidentally or with symptoms of hydrocephalus. Due to paucity of studies exploring this tumour type, the objective was to determine the medium- to long-term outcome of intracranial subependymoma treated by surgical resection.

METHODS

Retrospective case note review of adults with intracranial WHO grade 1 subependymoma diagnosed between 1990 and 2015 at the Walton Centre NHS Foundation Trust was undertaken. Tumour location, extent of resection (defined as gross total resection (GTR), sub-total resection (STR) or biopsy) and the WHO performance status at presentation and through follow-up were recorded.

RESULTS

Thirteen patients (7 males; 6 females) with a mean age of 47.6 years (range 33-58 years) and a median follow-up of 46 months (range 25-220 months) were studied. Eight patients had symptomatic tumours (headache, visual disturbance); five had incidental finding. Tumours were most commonly located in the fourth ventricle (n = 8). The performance status scores at diagnosis were 0 (n = 8) and 1 (n = 5). The early post-operative performance status scores at 6 months were 0 (n = 5) and 1 (n = 8) and at last follow-up were 0 (n = 11) and 1 (n = 2). There was no evidence of tumour re-growth following GTR or STR. The commonest complication was hydrocephalus (n = 3).

CONCLUSION

Subependymoma are indolent tumours. No patients exhibited a worsening of performance status at medium- to long-term follow-up and there were no tumour recurrence suggesting a shorter follow-up time may be sufficient. Surgical resection is indicated for symptomatic tumours or those without a clear imaging diagnosis. Incidental intraventricular subependymoma can be managed conservatively through MRI surveillance.

Posterior Fossa Tumors

Pediatric brain tumors are the leading cause of death from solid tumors in childhood. The most common posterior fossa tumors in children are medulloblastoma, atypical teratoid/rhabdoid tumor, cerebellar pilocytic astrocytoma, ependymoma, and brainstem glioma. Location, and imaging findings on computed tomography (CT) and conventional MR (cMR) imaging may provide important clues to the most likely diagnosis. Moreover, information obtained from advanced MR imaging techniques increase diagnostic confidence and help distinguish between different histologic tumor types. Here we discuss the most common posterior fossa tumors in children, including typical imaging findings on CT, cMR imaging, and advanced MR imaging studies.

Pediatric brain tumors

Pediatric brain tumors are the most common solid tumor of childhood. This article focuses on the metabolic signature of common pediatric brain tumors using MR spectroscopic analyses.

[Imaging of lateral ventricle tumors]

Lateral ventricular neoplasms are rare, and account for 50% of all intraventricular tumors in adults and 25% in children. Although these neoplasms are easily detected with computed tomography (CT) and magnetic resonance imaging (MRI), both techniques are relatively unspecific in identifying the type of tumor. However, few imaging patterns are specific for a particular pathological process and useful conclusions can be made from the morphological appearance of the lesion, its location and enhancement pattern. The aim of this article was to review and illustrate the CT and MRI findings of a wide spectrum of tumors of the lateral ventricle. We reviewed choroid plexus tumors, meningioma, subependymal giant cell astrocytoma, central neurocytoma, and less frequent lesion such as lymphoma and metastases.

[Intracranial ependymomas: retrospective study of 16 cases]

PURPOSE

To report the epidemiological, clinical aspects and therapeutic results of intracranial ependymomas in Morocco.

PATIENTS AND METHODS

Our retrospective study concerned 16 cases of intracranial ependymomas, treated from January 1995 to December 2002 at the radiotherapy department of Ibn Rochd Hospital of Casablanca, Morocco.

RESULTS

The average age was 15 years and complete surgery was possible in two cases. All the patients received cranial radiotherapy, combined with chemotherapy in six cases. Overall survival and progression-free survival at 5 years were respectively 50% and 31%. Eleven patients had local recurrence after an average period of 21 months. Progression-free survival at 5 years was better if complete resection: 100% vs. 28.6% in cases of incomplete resection, and depending on the histological type with 50% for classic ependymomas and 16.6% for anaplastic.

CONCLUSION

Ependymomas are rare tumors and complete resection is the standard treatment followed by postoperative radiotherapy. The place of chemotherapy remains to be defined.

Ependymomas in adults

Ependymomas are rare primary central nervous system tumors in adults. They occur most commonly in the spinal cord, where histopathologic evaluation is critical to differentiate the grade I myxopapillary ependymoma from the grade II ependymoma or grade III anaplastic ependymoma. Brain ependymomas are either grade II or III. Treatment for all grades and types includes maximum surgical resection. For myxopapillary ependymoma, complete removal while maintaining capsule integrity may be curative. Some grade II ependymomas may be observed carefully after imaging confirms complete resection, but grade III tumors require adjuvant radiation treatment. Radiation commonly is given to the region of tumor, except in cases in which there is imaging or cerebrospinal fluid evidence of tumor dissemination. Chemotherapy has not been studied extensively, although most reports suggest only modest benefit. Ongoing laboratory studies have uncovered important signal transduction pathways that may be better therapeutic targets, leading to the development of clinical trials using targeted agents.

[Supratentorial tumors]

Magnetic resonance imaging is a routine diagnostic measure for a suspected intracerebral mass. Computed tomography is usually also indicated. Further diagnostic procedures as well as the interpretation of the findings vary depending on the tumor location. This contribution discusses the symptoms and diagnostics for supratentorial tumors separated in relation to their intra- or extracranial location. Supratentorial tumors include astrocytoma, differentiated by their circumscribed and diffuse growth, ganglioglioma, ependyoma, neurocytoma, primitive neuroectodermal tumors (PNET), oligodendroglioma, dysem-bryoplastic neuroepithelial tumors (DNET), meningoangiomatosis, pineal tumors, hamatoma, lymphoma, craniopharyngeoma and metastases. The supratentorial extracranial tumors include the choroid plexus, colloid cysts, meningeoma, infantile myofibromatosis and lipoma. The most common sub-forms, especially of astrocytoma, will also be presented.

Infratentorielle Tumoren

This article gives an overview concerning the typical infratentorial tumors of adults.

Differenzialdiagnose von Raumforderungen im Kleinhirnbr�ckenwinkel

Most of the space demands in the cerebellopontine angle lie extra-axially. Important structures run within the cisterns of the cerebellopontine angle, such as the trigeminal, facial and vestibulocochlear nerves as well as the anterior inferior and posterior inferior cerebellar arteries and the veins which lead to the petrosal sinus. The most common space demands are caused by acoustic neuromas, meningeomas, vascular ectasia and aneurysms. Less common are epidermoid and other schwannomas as well as metastases, paragangliomas and arachnoidal cysts. Intra-axial tumours in the area of the cerebellopontine angle include the medulloblastoma, astrocytoma and the ependymoma, which occurs predominantly in children, in addition to the uncommon choroid plexus papilloma. Nearby, there are also space demands around the petrous bone, such as cholesterol granuloma, malignant otitis media, paraganglioma and metastases. For differential diagnosis, an understanding of the space requirements of the tumours in the cerebellopontine angle is needed in addition to knowledge of the anatomical structures.