Magnetic resonance imaging findings of extraventricular anaplastic ependymoma: A report of 11 cases

Abstract

Abstract. Anaplastic ependymomas are rare malignant tumors of the central nervous system. Few studies are available regarding their neuroradiological characteristics. The present study aimed to retrospectively review a series of patients with extraventricular anaplastic ependymoma and to analyze the magnetic resonance imaging (MRI) characteristics to distinguish anaplastic ependymoma from other intracranial tumors. The clinical and pathological images of 11 patients who presented with histologically proven anaplastic ependymoma at Nanfang Hospital (Southern Medical University, Guangzhou, Guangdong, China) between September 2004 and March 2015 were retrospectively reviewed. MRI scans were obtained in all 11 cases. Computed tomography scans were obtained in only 3 cases. In total, 8 tumors were located at the supratentorial parenchyma, and 3 tumors were derived from the cerebellar hemisphere. Images displayed quasi-circular (4/11), irregularly-lobulated (7/11) variable-intensity masses. The masses presented with cysts or necrosis (8/11), hemorrhage (7/11), marked (9/11) or mild (2/11) enhancement, and moderate (4/11), mild (3/11) or absent (4/11) peritumoral edema. The tumors were also frequently closely associated with the lateral ventricle (6/11). Tumors appeared isointense to hypointense on T1-weighted imaging (T1WI) and heterogeneously hyperintense or hypointense on T2WI, demonstrating wreath-like and ring-like characteristics, with intratumoral nodules (3/11) or marked flake-like inhomogeneous (6/11) enhancement on post-contrast MRI. Only 2 solid lesions showed mild enhancement (2/11). Although the MRI features of the extraventricular anaplastic ependymomas varied and were non-specific, these characteristic MRI findings, combined with the locations of the lesions, the age of onset and the short disease course, could be useful in differentiating anaplastic ependymomas from other intracranial neoplasms in the future.

MRI Features of Intracranial Anaplastic Ependymomas: A Comparison of Supratentorial and Infratentorial Lesions

“…Intratumoral hemorrhage indicated high-grade malignancy and extensive, abnormal vascularization (8). Previous studies demonstrated that cysts or necroses are features of anaplastic ependymomas, especially supratentorial neoplasms (2,7,(22)(23)(24). Cysts (particularly diameter larger than 1 cm) are frequently observed in supratentorial ependymomas, whereas infratentorial ependymomas tended to be associated with solid neoplasms (22,26).…”

“…Ependymomas, which are central nervous system (CNS) tumors, are commonly found in the fourth ventricle and arise from ependymal cells lining the ventricular system ( 1 ). Moreover, these tumors can occur anywhere within and even outside the CNS ( 2 – 4 ). Based on the World Health Organization (WHO) 2016 classification system, ependymomas are divided into three histological grades: grade I–III ( 5 ).…”

“…Given that studies of anaplastic ependymoma are limited by its low incidence, the accuracy of preoperative diagnosis is very low. Several previous reports of anaplastic ependymomas have described their imaging features ( 2 , 6 – 8 ), and most of these studies were case reports. Similar to grade II ependymomas, intracranial anaplastic ependymomas are also located infratentorially or supratentorially.…”

Intracranial ependymomas: The role of advanced neuroimaging in diagnosis and management

“…DWI may help in identifying areas of hypercellularity, characterised by signs of restricted diffusion. 23…”

The role of clinical factors and immunocheckpoint molecules in the prognosis of patients with supratentorial extraventricular ependymoma: a single-center retrospective study

“…Ependymomas are rare neoplasms of the central nervous system (CNS), accounting for 3.14% of all CNS tumors or 3–9% of all intracranial glial neoplasms (Chen et al 2013 ). Among intracranial ependymomas, 60% are infratentorial, and 40% are supratentorial (Leng et al 2016 ). Supratentorial extraventricular ependymoma (SEE) occurs outside the ventricular system of the brain and accounts for approximately 50% of supratentorial ependymomas (Wang et al 2018 ).…”