Cancer Genetics and Epigenetics 2017, Vol.5, No.4, 17-24
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ependymomas are characterised by hypercellularity, cellular and nuclear pleomorphism, frequent mitosis,
pseudopalisading necrosis and endothelial proliferation an associated with higher risk of recurrence, or drop
metastasis (Trivedi, 2017; Ferris, 2017; Sun, 2017; Takeda, 2017). Extra-CNS metastasis, although extremely rare,
have been described in isolated works of the literature (Marsecano, 2017). The present case, which belongs to
WHO Grade III shows an extra-axial origin and grows directly into the CPA region.
2.2 Clinical characteristics
Of the previously reported 5 CPA ependymal tumors comprising 3 males and 2 females with a mean age of 52.8
years, (range from 22-78 years) seen in Table 1; whereas, of the 4 intracranial extra-axial anaplastic ependymoma
cases compromising 3 males and 1 females with a mean age of 32.3 years, (range from 17-47 years) seen in Table
2. Preoperative symptoms were associated with headache, vomiting and seizure due to intracranial hypertension or
neurologic focal deficits with a mean symptom duration of 3.4 months (range 3 days – 6 months) and 26.7 months
(range 3 weeks – 80 months) respectively. From Yang Yang et al’ s review of these 17 extra-axial ependymal cases,
there were no data correlating the duration of symptoms with the lesion size (Yang, 2016). Our present case
developed nonspecific symptoms for 20 years. This finding is different from data in previous report by Reni, M.,
et al. that has found more rapid signs and symptoms for anaplastic ependymomas. CPA lesions most commonly
present with symptoms related to the brainstem or cranial nerves compressed by or involved with the lesion (Reni,
2007). Clinical presentation is non-specific, and depends on the size, location and malignancy of the tumor.
Therefore, CPA ependymomal tumors are difficult to be discriminated from other neoplasms based on their
nonspecific clinical presentations alone.
Ependymal tumors are more commonly infratentorial (60%), particularly in the fourth ventricle, and in 50% of
cases can extend into the subarachnoid space of the cisterna magna or the CPA space, or involve the medulla and
upper cervical cord. However, anaplastic ependymomas are extremely rare, particularly regarding CPA space. To
date, only 19 cases of intracranial extra-axial ependymomas have been reported in English literarture since 1976
when first reported by Hanchey et al (Hanchey, 1976). 8 of these cases were infratentorial (5 out of 8 cases at CPA
space), and the other 11 cases were supratentorial. 4 of these 19 cases were anaplastic ependymomas, but none of
them involved CPA region (Yang, 2016). To the best of our knowledge, here is the first case report of CPA
anaplastic ependymoma in the literature. Of these 19 previously reported cases, intracranial extra-axial ependymal
tumors appear more commonly in adults. With respect to anaplastic epedymomas, these 4 cases present with a
young adult predominance. Due to the paucity of data regarding intracranial extra-axial ependymomas,
particularly anaplastic ependymomas in the literature, there are no symptoms or radiographic features that are
pathognomonic for this spectrum of neoplasms. Therefore, more cases are expected to be collected for further
study.
2.3 MRI findings
In terms of radiological findings, most published documents about ependymal tumors focus more on
ependymomas due to the relative common cases. The imaging features of intracranial extra-axial ependymomas
need to be accumulated. Magnetic resonance imaging is thought to be the imaging modality of choice for showing
the internal features of the lesion and superior soft tissue contrast. Because of calcification, necrosis, hemorrhage,
or cystic components (Table 1), most cases were mixed-intensity on both T1- (hypointense to isointense) and T2-
(isointense to hyperintense) weighted images, as similarly detected in out case; however, 2 out of 4 anaplastic
ependymomas showed isointense on both T1- and T2-weighted images (Table 2), and most lesions had
heterogeneous enhancement. Similarly, perilesional
edema, which occurred infrequently, was not detected in
present case. Although there is no consensus on imaging, absence of perilesional edema has been reported common
and more easily discerned radiologically for ependymal tumors. Ma Reni et al suggested more pronounced contrast
enhancement in anaplastic tumors. This finding is consistent with present case. Owing to the paucity of
radiographic appearances, there is no consensus regarding the radiological diagnosis.
