Hemifacial spasm caused by epidermoid tumor at cerebello pontine angle.
ABSTRACT Hemifacial spasm (HFS) is almost always induced by vascular compression but in some cases the cause of HFS are tumors at cerebellopontine angle (CPA) or vascular malformations. We present a rare case of hemifacial spasm caused by epidermoid tumors and the possible pathogenesis of HFS is discussed. A 36-year-old female patient presented with a 27-month history of progressive involuntary facial twitching and had been treated with acupuncture and herb medication. On imaging study, a mass lesion was seen at right CPA. Microvascular decompression combined with mass removal was undertaken through retrosigmoid approach. The lesion was avascular mass and diagnosed with an epidermoid tumor pathologically. Eventually, we found a offending vessel (AICA : anterior inferior cerebellar artery) compressing facial nerve root exit zone (REZ). In case of HFS caused by tumor compression on the facial nerve REZ, surgeons should try to find an offending vessel under the mass. This case supports the vascular compression theory as a pathogenesis of HFS.
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ABSTRACT: Hemifacial Spasm (HS) occurs idiopathically or secondary to the lesions compressing the root exit zone of the facial nerve symptomatically. Symptomatic HS is generally due to vascular compression. We report on a 23-year-old male with right sided HS for a month. Magnetic resonance imaging (MRI) of the brain revealed a well-demarcated epidermoid cyst in the right cerebellopontine cistern. It was hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging without contrast enhancement, hyperintense on DWI, and slightly hypointense on ADC relative to the brain. Although it caused shifting of the pons and medulla to the left side and compression of the right cerebellar peduncles and fourth ventricle, the sole symptom of the patient was HS. Clinicians are advised to request MRI/scan for brainstem lesions from the patients with HS. Epidermoid cysts in cerebellopontine cistern may present with HS as the sole symptom.Journal of neurosciences in rural practice. 09/2012; 3(3):344-6.
Article: Commentary.Journal of neurosciences in rural practice. 09/2012; 3(3):346-7.
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ABSTRACT: Although the mechanism of hemifacial spasm (HFS) is not yet well established, vascular compression of the facial nerve root exit zone and hyperexcitability of the facial nucleus have been suggested. We report a case of HFS in the setting of coinciding intracranial hemorrhage (ICH) of the pons and proximal ligation of the contralateral vertebral artery (VA) for the treatment of a fusiform aneurysm of the distal VA and discuss the possible etiologies of HFS in this patient. A 51-year-old male with an ICH of the pons was admitted to our hospital. Neuroimaging studies revealed an incidental fusiform aneurysm of the right VA distal to the origin of the posterior inferior cerebellar artery. Eight months after proximal ligation of the VA the patient presented with intermittent spasm of the left side of his face. Pre- and post-ligation magnetic resonance angiography revealed an enlarged diameter of the VA. The spasm completely disappeared after microvascular decompression.Journal of Korean Neurosurgical Society 01/2012; 51(1):59-61. · 0.60 Impact Factor
Hemifacial Spasm Caused by Epidermoid Tumor
at Cerebello Pontine Angle
Seok-Keun Choi, M.D., Bong-Arm Rhee, M.D., Young Jin Lim, M.D.
Department of Neurosurgery, School of Medicine, Kyung Hee University, Seoul, Korea
J Korean Neurosurg Soc 45 : 196-198, 2009
Hemifacial spasm (HFS) is almost always induced by vascular compression but in some cases the cause of HFS are tumors at cerebellopontine
angle (CPA) or vascular malformations. We present a rare case of hemifacial spasm caused by epidermoid tumors and the possible pathogenesis
of HFS is discussed. A 36-year-old female patient presented with a 27-month history of progressive involuntary facial twitching and had been
treated with acupuncture and herb medication. On imaging study, a mass lesion was seen at right CPA. Microvascular decompression combined
with mass removal was undertaken through retrosigmoid approach. The lesion was avascular mass and diagnosed with an epidermoid tumor
pathologically. Eventually, we found a offending vessel (AICA : anterior inferior cerebellar artery) compressing facial nerve root exit zone (REZ). In
case of HFS caused by tumor compression on the facial nerve REZ, surgeons should try to find an offending vessel under the mass. This case
supports the vascular compression theory as a pathogenesis of HFS.
KEY WORDS : Hemifacial spasm˙ Facial nerve ˙ Epidermal cyst.
Copyright ©2009 The Korean Neurosurgical Society
Print ISSN 2005-3711 On-line ISSN 1598-7876
Hemifacial spasm (HFS) is a most common hyperactive
cranial rhizopathy and presented with involuntary facial
twitching of unilateral facial muscles2). HFS is almost
always caused by vascular compression on the facial nerve
root exit zone (REZ) closely located at the brain stem. The
hypothesis of vascular compression is established by the
fact the involuntary facial movement disappears just after
microvascular decompression (MVD). However, the relation-
ship between the abnormal condition of nerve signals and
the facial muscles have not been clearly verified.
HFS can also be induced by benign tumors developed at
cerebellopontine angle (CPA) or in 4thventricle, glioma in
brain stem17), vascular malformations12), cysticercosis15)or
lipoma8). And, it has been also reported that the remote
lesion such as parotid gland tumor6,14)and remote menin-
giomas4)or contralateral lesions13,16)can induce the facial
involuntary movement. HFS caused by unusual cause can
be helpful to understand the mechanism generating the
facial symptom. We report a rare case that had a facial sy-
mptom caused by an epidermoid tumor.
A 36-year-old female patient presented with a 27-month
history of progressive involuntary facial twitching. Until
admission, the patient tried with acupuncture and herb
medication. On admission, she had no neurological deficit
on physical examinations. Magnetic resonance (MR) images
showed a mass lesion on right CPA (Fig. 1A, B). She
underwent mass removal by retromastoid suboccipital
approach and the tumor was located anterior to 7th, 8th
nerves and lower cranial nerves. The mass was avascular
and easily removable. We could define the 6thnerve, which
was displaced anteriorly by the mass. And, between the
tumor and 7th, 8thnerve complex there was a compressing
vessel, anterior inferior cerebellar artery (AICA), but the
arachnoid band was adhesive between facial nerve and
offending vessel and thus dissected cautiously (Fig. 2).
Teflon was then inserted. Post-operatively the facial
involuntary movement was relieved but the facial palsy was
• Received : June 3, 2008 •Accepted : February 22, 2009
• Address for reprints : Seok-Keun Choi, M.D.
Department of Neurosurgery, School of Medicine, Kyung Hee University,
Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Korea
Tel : +82-2-958-8385, Fax : +82-2-958-8380
E-mail : firstname.lastname@example.org
Hemifacial Spasm Caused by Epidermoid Tumor | SK Choi, et al.
noticed that was relieved at 17 days after the surgery.
HFS is a hyperactive cranial rhizopathy which is gener-
ated at the facial REZ at pontomedullary junction10). The
generally accepted hypothesis of HFS is that elongated
vessels as a result of aging process irritate facial REZ. At
the point where the vessel is compressing, atypical neuro-
nal signal is generated and conducted to facial muscles1).
But whether the actual site of the ephapsis is at the site of
the lesion or at a nuclear level due to hyperexcitability of the
facial motor nucleus is still controversial. Another hypo-
thesis is that hypersensitivity of facial nucleus can cause the
facial involuntary movement and it is supported by the
phenomenon that HFS could be induced by brainstem
As for HFS induced by benign tumors, many authors
have suggested the mechanisms, which might induce the
facial symptom. In many cases, it was suggested that the
vascular compression under the tumor is the cause of the
HFS5,7,9). And, several authors suggested that in spite of the
remote meningioma4)or contralateral
lesions13,16), there was a possibility of
the offending vessel by the distorted
brain structure with large mass lesion.
In this case, we found the definite
offending vessel, which was displaced
by epidermoid cyst, and compressing
the facial REZ.
However, others had reported that
there were no compressing vessels un-
der the tumor8,9). Nagata et al.12)sug-
gested that there was another cause in-
ducing the symptom. He had found
that there was no artery compressing the facial nerve at the
REZ and in three cases, the HFS disappeared after remo-
val of the tumor in contact with the facial nerve and pro-
posed that the cause of HFS was the compression or enca-
sement of the facial nerve by the tumor was the pathoge-
Another possible hypothesis of facial symptom is by the
changes of arachnoid membrane. Some authors have
reported that arachnoid adhesion can be a possible evi-
dence of a prior inflammatory process and may force the
pulsatile arterial branches into constant contact with the
7thand 8thnerve complex but these hypothesis were not
verified18). Kobata et al.11)reported the large cases of
unusual causes of HFS by 30 epidermoids but there were
only 2 cases of HFS patients. He proposed that arachnoid
adhesion might be a cause as one of the recurrence of
symptom. In our case, after the mass removal, the arachnoid
band between AICA and facial nerve was partially remained
because it was very adhesive and had a possibility of facial
nerve tearing when removed. It may be possible that
arachnoid bands between the offending vessel and facial
nerve can be an aberrant conduction. But, we decompressed
Fig. 1. Fluid-attenuated inversion recovery magnetic resonance (MR) image showing the iso-signal intensity lesion displacing brain stem at right cerebello-
pontine angle (A) and three-dimensional short-range reconstruction MR image demonstrating the offending vessel, which is displaced by the mass (B).
Pathologically, the tumor contains laminated keratin material lined by stratified squamous epithelium (Hematoxilyn-Eosin stain, ×100) (C).
Fig. 2. A:On operative finding, the lesion is avascular and whitish mass. B:After the mass removal,
anterior cerebellar artery is detected under the tumor as a compressing vessel but arachnoid band
between offending vessel and facial nerve is found (B).
J Korean Neurosurg Soc 45 | March 2009
the facial nerve REZ as possible as we could to detach
from the facial REZ.
This case can support the vascular compression hypothe-
sis in case of HFS caused by tumors lesion at CPA. And, it
is suggested that surgeons should try to find the underlying
offending vessel displaced by the tumor mass.
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