Case Report
F L U I D - F L U I D L E V E L W I T H I N T H E E P E N D Y M O M A O F T H E
P O S T E R IO R F O S S A
G a z a n fe r Ekinci, M .D .,* / Feyyaz B altacıoğlu, M .D .,*
Ö zlem K u rtk a y a , M .D .,** / Nurten Andaç, M .D .,*
İhsan N . A k p ın a r, M .D .,* / Canan Erzen, M .D .*
* D e p a r t m e n t o f R a d io lo g y , S c h o o l o f M e d ic in e , M a r m a ra U n iv e rs ity , Is ta n b u l, T u rk e y . * * S u b -d e p a r tm e n t o f n e u r o p a th o lo g y , D e p a r tm e n t o f P a th o lo g y , S c h o o l o f M e d ic in e ,
M a r m a r a U n v e rs ity , Is ta n b u l, T u rk e y .
ABSTRACT
W e report an unusual c a se of an ependym om a of the posterior fo ssa which has an unusual location and radiological findings. MR imaging showed a mixed signal intensity containing m ass centered over cerebellopontine angle cistern containing multiple cystic com ponents with fluid-fluid levels a s a result of intratumoral hem orrhage.
K ey W o rd s :
E p e n d ym o m a, Intratum oralhem orrhage, Fluid-fluid level
Ependym om as represent from 2% to 8% of all primary intracranial brain tum ors. T h e y constitute 15% posterior fo ssa neoplasm s in childhood and are the third most common pediatric brain tumor (1). The peak age range is 1 to 5 years but there is a se co n d sm a lle r p eak in the m id-30s. Approxim ately 6 0% of intracranial ependym om as are located in the posterior fo ssa, and 40% are found above the tentorium. Ninety percent of infratentorial ependym om as occur in the fourth ventricle (2). W e present an unusual c a se of posterior fo ssa ependym om a centered over the
cerebellopontine angle (C P A ) cistern with atypical imaging findings.
CASE
A 37-year-old man presented with complaints of headaches, vertigo, falls, vomiting and facial pain in the distribution of the first division of the trigeminal nerve. On neurological exam ination, the positive findings were mild facial p aresis and gait ataxia. Audiometry revealed mild hearing loss in the right ear. Cranial MR imaging showed a nonhomogenously faint enhancing C P A m ass with mutiple cystic components that contained fluid-fluid levels as a result of hemorrhage (Figs 1, 2, 3). The m ass centred over the right C P A with extension into the prepontine cistern and towards the right cavernous sinus resulting in com pression of the right cerebellar pedincle, fourth ventricle and pons, with a sm all com ponent entering the m eatus a co u stics internus. A sm all component of the m ass w as also present in the right foramina Lu sch ca and lateral re ce ss of the fourth ventricle. Since the bulk of the m ass w as seen in the C P A , it w as
( A c c e p t e d 4 J u n e , 2 0 0 2 ) M a r m a r a M e d i c a l J o u r n a l 2 0 0 2 ; 1 5 ( 1 ) : 4 7 - 4 9
Correspondance to: Gazanfer Ekinci, M.D. - Department of Radiology. Marmara University Hospital, 81190 Altunizade. istanbul, Turkey.
e.mail address: gazanfere@hotmail.com
Gazanfer Ekinci, et al
F i g . l : Axial FSE T2W (TR/TE: 3 0 0 0 /9 0 m se c , ET: 16) im age. T h e m a s s c o n ta in s c y s ts with fluid-fluid level (arrow s). A sm all part of fluid-fluid level containing m a s s is s e e n in th e right foram ina L u sch ca a n d lateral r e c e s s of th e fourth ventricle. T h ere is minimal d isp la c e m e n t of th e m edulla to th e right a n d c o m p re ss io n of th e fourth ventricle.
thought that the m a ss w a s a C P A m a ss. Fifth cranial nerve could not be identified within the m ass. T h e c ysts showed faint rim enhancem ent. T h e re w a s m oderate ve n tricu lo m e g aly. C T imaging showed no calcification in the m ass or bony c h a n g e s in the posterior fo s s a . T h e preop erative differential d ia g n o se s w ere epidermoid tumor and cystic neurinom a.
The patient underwent total removal via the right transtentorial ap p ro ach . H istopathologic diagnosis w as low-grade ependym om a based on com bined histom orphological and im m unohistochem ical findings.
Postoperatively the patient did well and w as d isch arg e d from the hospital on the sixth postoperative day.
F i g . 2 : Axial n o n -e n h a n c e d S E T1W (TR/TE: 4 4 0 /1 0 m se c) im a g e . T h e le sio n is s e e n a s h e te r o g e n e o u s ly hyp o in ten se.
F i g . 3 : Axial c o n tra st e n h a n c e d S E T1W (TR/TE: 440/11 m sec) im age. T h e m a s s s h o w s h e te ro g e n e o u s a n d faint e n h a n c e m e n t.
DISCUSSION
The ependym om a is a thin layer of ciliated or colum nar epithelium that lines the ventricular w alls and central canal of the spinal cord (3). E p e n d ym o m as are slow -grow ing lobulated neoplasm s that a rise from ependym al cells. Although ependym om as most frequently occur in intraventricular or intraspinal locations, they have also been reported in a variety of soft tissue locations including lung, m ediastinum , ovary, and subcutaneous tissu e s (4-8). Th e most common site for ependym om as is the roof, floor or lateral m edullary velum of the fourth ventricle (9, 10). Ependym om as frequently grow out of the fourth ven tricle and into surrounding c iste n s and foram ina. Approxim ately 15% extend into the C P A through the foramine L u sch ca , and up to 60% grow through the foram ina M agendie into the citern a m ag na, through the foram en magnum, and into the cervical spinal canal (11). O ccasionally, ependym om as of the C P S can a rise without e vid e n ce of tumor within the ventricle or lateral re c e ss. The occurrence of e xtra -a xia l, e x tra ve n tricu la r intracran ial ep en d ym o m as is u n u su al. A few c a s e s of intracranial extra-axial ependym om as have been reported (12-17). Most of those are supratentorial c a s e s (13, 14, 16). Th ere are a few reported extra-axial ependym om a c a s e s of the posterior fo ssa (12, 15, 17). Extraventricular and extra- axial ependym om as are believed to originate
Posterior fossa ependymoma
from glial rests deposited in the subarachnoid sp a c e or m en ing e s during em bryological developm ent (12, 13).
In our c a se , Imaging studies and intraoperative observation clearly established that the m ass w a s centred over the C P A cistern. It w as hard to tell that the m ass originated from the fourth ven tricle and extend ed Into the C P A . Th e uniqueness of our c a se Is that the m ass had multiple cystic com ponents that contained fluid- fluid levels probably a s a result of hemorrhage. T h e se radiological findings are seen very rarely in ependym om as. In review of the literature, there is no illustrated c a se of fluid-fluid levels in ependym om as.
A s a conclusion, ependym om as should also be included in the differential diagnosis of the fluid- fluid levels containing multicystic m a sse s of the C P A of the posterior fo ssa a s an uncommon ca u se .
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