Radiologic-Pathologic
Ependymoma
of the
Martin R. Prince1 and
Downloaded from www.ajronline.org by 61.3.112.17 on 10/04/15 from IP address 61.3.112.17. Copyright ARRS. For personal use only; all rights reserved
Conferences
Fourth
of the Massachusetts
General Hospital
Ventricle
Felix S. Chew
The circumference of the head of a 17-month-old girl with lethargy, nausea, and irritability was above the 95th percentile for age. CT of the brain revealed a polypoid mass in the fourth ventricle with proximal hydrocephalus and decreased periventricular attenuation from transependymal flow of CSF (Fig. 1). MR imaging showed the mass arising from the floor of the fourth ventricle and extending bilaterally through the foramina of Luschka into the cerebellopontine angle cisterns. IV administration of gadopentetate dimeglumine produced regional mass effect and minimal heterogeneous enhancement. The intralesional signal was heterogeneous on T2-weighted images. After surgical resection, gross examination revealed a solid tumor with regions of necrosis and hemorrhage. Microscopic findings were of a fairly cellular tumor with prominent perivascular pseudorosettes. The final pathologic diagnosis was ependymoma. Ependymomas arise from the layer of differentiated ependymal cells that line the ventricles of the brain and the central canal of the spinal cord. Ependymomas constitute 8% of intracranial gliomas in children and 1-6% of intracranial gliomas in adults. Although they may occur at any age and anywhere along the ependymal portion of the neural axis, most are found in children in the first decade of life and are located on the floor of the fourth ventricle. Symptoms are usually the result of space-occupying effects; location in the fourth ventricle leads to obstructive hydrocephalus [1]. Most ependymomas grow slowly and are well-circumscribed. Soft and often frondlike,
they have a propensity for plastic growth and may protrude the ventricular foramina into the subarachnoid space. Approximately
images, can
be
50%
of lesions
appear
as calcified
on
through
CT.
On
MA
the mixed signal characteristics of solid portions of tumor due to hemorrhage, necrosis, tumor vascularity, or calcifica-
tion; thus differentiation
of ependymoma
from other
lesions
is based
on location and morphology rather than appearance [2]. Treatment includes surgery and irradiation, but the prognosis is generally poor because of the dangerous location and the technical difficulty in performing a complete resection [3]. Ependymomas can disseminate throughout the subarachnoid space and in rare instances can spread beyond the CNS. Cytologic features of malignancy are usually absent, but the histologic appearance does not correlate well with prognosis; one series reported a 100% mortality rate within 3 years of diagnosis [4]. REFERENCES 1 . Rubinstein LI. Tumors of the central nervous system. Washington, DC: Armed Forces Institute of Pathology, 1972:104-114 2. Spoto GP, Press GA, Hesselink JR, Soloman M. Intracranial ependymoma and subependymoma: MR manifestations. AJNR 199011:83-91 3. Shuman AM, Alvord EC, Leech RW. The biology of childhood ependymomas. Arch Neurol 1975;32:731-739 4. Ross GW, Rubenstein U. Lack ofhistopathological correlation of malignant ependymomas with postoperative survival. J Neurosurg 1989;70:31-36
.,
;---
J.,
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Fig. 1.-Ependymoma of fourth ventricle. A, Axial CT scan shows polypold lesion In fourth ventricle and hydrocephalus. Lesion Is not calcified. B, Ti-weighted coronal MR Image shows lesion arising from fleer of fourth ventricle. C, Photomicrograph of histologic specimen shows three blood vessels surrounded by eosinophilic cuffs of tumor cell cytoplasm separating tumor cells from vessel walls (perivascular pseudorosettes). Nuclei are of uniform size and shape. (H and E, original magnification x390)
nuclei of
radiologic-pathologic correlation conferences conducted by Jack Wittenberg. Pathology editor: Andrew E. Rosenberg. Radiology editors: Felix Daniel P. Barboriak, William E. Palmer, Daniel I. Rosenthal. authors: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 32 Fruit St., Boston, MA 021 14. Address reprint to F. S. Chew.
From the weekly requests
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Chew, I Both
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AJR 157:1278,
December
1991 0361-803X/91/1576-1278
© American
Roentgen
Ray Society
Ependymoma
of the
Martin R. Prince1 and
Downloaded from www.ajronline.org by 61.3.112.17 on 10/04/15 from IP address 61.3.112.17. Copyright ARRS. For personal use only; all rights reserved
Conferences
Fourth
of the Massachusetts
General Hospital
Ventricle
Felix S. Chew
The circumference of the head of a 17-month-old girl with lethargy, nausea, and irritability was above the 95th percentile for age. CT of the brain revealed a polypoid mass in the fourth ventricle with proximal hydrocephalus and decreased periventricular attenuation from transependymal flow of CSF (Fig. 1). MR imaging showed the mass arising from the floor of the fourth ventricle and extending bilaterally through the foramina of Luschka into the cerebellopontine angle cisterns. IV administration of gadopentetate dimeglumine produced regional mass effect and minimal heterogeneous enhancement. The intralesional signal was heterogeneous on T2-weighted images. After surgical resection, gross examination revealed a solid tumor with regions of necrosis and hemorrhage. Microscopic findings were of a fairly cellular tumor with prominent perivascular pseudorosettes. The final pathologic diagnosis was ependymoma. Ependymomas arise from the layer of differentiated ependymal cells that line the ventricles of the brain and the central canal of the spinal cord. Ependymomas constitute 8% of intracranial gliomas in children and 1-6% of intracranial gliomas in adults. Although they may occur at any age and anywhere along the ependymal portion of the neural axis, most are found in children in the first decade of life and are located on the floor of the fourth ventricle. Symptoms are usually the result of space-occupying effects; location in the fourth ventricle leads to obstructive hydrocephalus [1]. Most ependymomas grow slowly and are well-circumscribed. Soft and often frondlike,
they have a propensity for plastic growth and may protrude the ventricular foramina into the subarachnoid space. Approximately
images, can
be
50%
of lesions
appear
as calcified
on
through
CT.
On
MA
the mixed signal characteristics of solid portions of tumor due to hemorrhage, necrosis, tumor vascularity, or calcifica-
tion; thus differentiation
of ependymoma
from other
lesions
is based
on location and morphology rather than appearance [2]. Treatment includes surgery and irradiation, but the prognosis is generally poor because of the dangerous location and the technical difficulty in performing a complete resection [3]. Ependymomas can disseminate throughout the subarachnoid space and in rare instances can spread beyond the CNS. Cytologic features of malignancy are usually absent, but the histologic appearance does not correlate well with prognosis; one series reported a 100% mortality rate within 3 years of diagnosis [4]. REFERENCES 1 . Rubinstein LI. Tumors of the central nervous system. Washington, DC: Armed Forces Institute of Pathology, 1972:104-114 2. Spoto GP, Press GA, Hesselink JR, Soloman M. Intracranial ependymoma and subependymoma: MR manifestations. AJNR 199011:83-91 3. Shuman AM, Alvord EC, Leech RW. The biology of childhood ependymomas. Arch Neurol 1975;32:731-739 4. Ross GW, Rubenstein U. Lack ofhistopathological correlation of malignant ependymomas with postoperative survival. J Neurosurg 1989;70:31-36
.,
;---
J.,
.
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-:
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.
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,
Fig. 1.-Ependymoma of fourth ventricle. A, Axial CT scan shows polypold lesion In fourth ventricle and hydrocephalus. Lesion Is not calcified. B, Ti-weighted coronal MR Image shows lesion arising from fleer of fourth ventricle. C, Photomicrograph of histologic specimen shows three blood vessels surrounded by eosinophilic cuffs of tumor cell cytoplasm separating tumor cells from vessel walls (perivascular pseudorosettes). Nuclei are of uniform size and shape. (H and E, original magnification x390)
nuclei of
radiologic-pathologic correlation conferences conducted by Jack Wittenberg. Pathology editor: Andrew E. Rosenberg. Radiology editors: Felix Daniel P. Barboriak, William E. Palmer, Daniel I. Rosenthal. authors: Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 32 Fruit St., Boston, MA 021 14. Address reprint to F. S. Chew.
From the weekly requests
.z:
..
.
Q
Chew, I Both
.
-
___..;
S.
:
‘
. .
..-‘
AJR 157:1278,
December
1991 0361-803X/91/1576-1278
© American
Roentgen
Ray Society
