imGNS

Case report

9 Springer-Verlag 1991

Child's Nerv Syst (1991) 7:59-61

Giant middle cerebral aneurysm presenting as hemiathetosis in a child
and its spontaneous thrombosis
A. Rashid Choudhury 1, Nizar H. AI Amiri a, Khalaf R. AI Moutaery t, Mohamed Aabed 2, and M. Keith Strelling 3
1 Department of Neurosurgery, 2 Department of Neuroradiology, and 3 Department of Paediatrics, Riyadh Armed Forces Hospital,
P.O. Box 7897, Riyadh 11159, Kingdom of Saudi Arabia
Received November 15, 1989

Abstract. A 1 0 - y e a r - o l d girl p r e s e n t e d with a 6-week
h i s t o r y of g r a d u a l l y increasing, a b n o r m a l m o v e m e n t s
a n d w e a k n e s s of the right u p p e r a n d l o w e r limbs. T h e r e
were n o features of raised i n t r a c r a n i a l pressure. C o m p u t ed t o m o g r a p h y scan a n d m a g n e t i c r e s o n a n c e i m a g i n g
( M R I ) of the b r a i n s h o w e d the features of a p a r t i a l l y
t h r o m b o s e d g i a n t m i d d l e c e r e b r a l a r t e r y a n e u r y s m , loc a t e d d e e p in the left l e n t i f o r m region a n d c o m p r e s s i n g
the b a s a l g a n g l i a a n d the m e s e n c e p h a l o n . T h e a n g i o g r a m
c o n f i r m e d the a n e u r y s m a n d its origin f r o m the m a i n
t r u n k of the a r t e r y with o c c l u s i o n of all the branches. A
direct a p p r o a c h was u n s u i t a b l e for the t r e a t m e n t of the
a n e u r y s m , so a n e m b o l i z a t i o n p r o c e d u r e to occlude the
neck of the a n e u r y s m was c o n s i d e r e d . D u r i n g the w a i t i n g
p e r i o d , the p a t i e n t i m p r o v e d a n d b e c a m e a s y m p t o m a t i c .
F o l l o w - u p M R I s h o w e d c o m p l e t e t h r o m b o s i s of the
a n e u r y s m a n d eventually, r e d u c t i o n in its size a n d m a s s
effect. T h e h e m i a t h e t o s i s m a y have been the result of
direct p r e s s u r e o n the b a s a l g a n g l i a b y the a n e u r y s m . T h e
s p o n t a n e o u s i n t r a - a n e u r y s m a l t h r o m b o s i s m a y have
been d u e to the m a s s i v e size of the a n e u r y s m a n d its
n a r r o w neck.

Key words: G i a n t a n e u r y s m - M i d d l e c e r e b r a l a r t e r y Spontaneous thrombosis - Hemiathetosis

A n e u r y s m s larger t h a n 2.5 c m in d i a m e t e r are c o n s i d e r e d
to be g i a n t a n e u r y s m s a n d are rare, c o m p r i s i n g a b o u t 5 %
of all i n t r a c r a n i a l a n e u r y s m s [5, 10]. A l t h o u g h a n e u r y s m s
are rare in c h i l d h o o d , there seems to be a slightly h i g h e r
p r o p o r t i o n of g i a n t a n e u r y s m s in this age g r o u p [8]. T h e y
u s u a l l y p r e s e n t either w i t h s u b a r a c h n o i d h e m o r r h a g e o r
p r o g r e s s i v e visual loss a n d h e a d a c h e d u e to their frequent
p r o x i m i t y to the c a r o t i d a n d o p h t h a l m i c arteries [4, 5,
8, 9]. Rarely, they m a y p r e s e n t as a s p a c e - o c c u p y i n g
lesion a n d p r o d u c e a c o n t r a l a t e r a l w e a k n e s s o r sensory
d i s t u r b a n c e [17]. We r e p o r t here a child with a g i a n t m i d Offprint requests to. A. R. Choudhury

dle c e r e b r a l a n e u r y s m w h o p r e s e n t e d with h e m i a t h e t o s i s
thrombosed spontaneously.

Case report
This 10-year-old girl was admitted to the Riyadh Armed Forces
Hospital with a 6-week history of abnormal movement and weakness of the right limbs. This was associated with slowness of speech.
These features were gradual in onset and slowly progressive. There
was no history of headache, paresthesia, visual disturbance, or fits.
She had increasing difficulty in writing and this led to her failing the
school examination. Her past medical history had been uneventful
and there was no family history of abnormal movement.
On 22 February 1989, examination revealed a healthy young
girl of average build. She was fully conscious and cooperative.
When she attempted a voluntary action, her right fingers went into
a slow, purposeless, continuous writhing movement. This was followed successively by flexion of the wrist, inward movement of the
forearm and arm toward her chest, and adduction with outward
movement of the whole limb. This was associated with elevation of
the inner border of the right foot with extension of the hallux,
abduction at the knee and flexion at the hip. These movements
disappeared at rest and during sleep. Neurological examination
revealed a right-sided upper motor-neuron-type facial palsy and a
mild spastic weakness (power: UK Medical Research Council)
grade 4 of the right upper and lower limbs. Her reflexes were brisk
on the right side with a right plantar extensor response. Her speech
was slow but clear. The rest of the neurological examination, including the fundi, was normal. The general physical examination revealed no abnormalities.
The results of the routine hematological and radiological investigations were normal. A computed tomography (CT) scan of the
brain showed a hyperdense mass lesion containing specks of peripheral calcification in the left temporal lentiform region measuring
4.5 x 3 cm and a mass effect with compression of the basal ganglia
and mesencephalon and a shift of the midline. After injection of a
contrast medium, the lesion showed well-marked homogeneous enhancement. Magnetic resonance imaging (MRI) showed a nonhomogeneous mass consisting of a larger area void of signal located
centrally and a smaller area peripherally with high signal intensity.
This mass was deep in the left lentiform region (Fig. 1), indicating
a giant aneurysm with peripheral thrombosis. It measured 4.5 x
3 cm, and produced a mass effect with compression of the basal
ganglia and mesencephalon, and a shift of the midline. A left carotid
angiogram (Fig. 2) confirmed a giant aneurysm arising from the
main trunk of the middle cerebral artery, with occlusion of all its
branches. It was partially thrombosed peripherally.

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Fig. 1. Initial axial magnetic resonance image (MRI) (spin echoT2-2100/100) showing a mass lesion in the left lentiform area with
void signal cent/rally and hyperintense signal peripherally, and
having a mass effect
Fig. 2. Left carotid angiogram. A-P view showing a partially thrombosed giant aneurysm arising from trunk of the middle cerebral
artery with absence of its branches

A direct approach was unsuitable for the treatment of the aneurysm. This was due to the nonfeasibility of external carotid-internal
carotid bypass because of occlusion of all the branches of the middle
cerebral artery. An embolization procedure was considered in order
to occlude the neck of the aneurysm. During a 2-month waiting
period, the condition of the patient improved. The weakness resolved, abnormal movements subsided and her speech returned to
normal. At this stage, follow-up MRI (Fig. 3)showed complete
thrombosis of the aneurysm; however, the mass effect remained
unchanged. MRI (Fig. 4) repeated 7 months later showed reduction
of the size of both the thrombosed aneurysm and the mass effect.
The patient remained well and asymptomatic.

Discussion
An extrapyramidal m o v e m e n t disorder has been reported
as a rare complication of intracranial space-occupying
lesions [1, 2, 6, 7, 14, 15]. In each case, the s y m p t o m s
resolved after removal of the lesion. Thus a causal relationship between the two has been thought to exist [12].
In our patient, the assumption of a causal relationship
between the hemiathetosis and the middle cerebral aneurysm is based on gradual resolution of the s y m p t o m s after
spontaneous thrombosis of the aneurysm.
Giant aneurysms have a pleomorphic pattern of clinical presentation [3]. Only 1 of 22 patients in Bull's series
[3] presented with a tremor in one a r m with associated
hemiparesis but no other extrapyramidal features. The
presentation was either headaches or visual disturbances
in 21 patients. In other series [4, 5, 8 - 1 0 , 17], no extrapyramidal syndrome has been described. Recently, Gross
[7] described a patient with a giant middle cerebral artery
aneurysm presenting as hemiparkinsonism. Following
surgery, the patient made an excellent recovery with complete resolution of the extrapyramidal features. In our
patient, the aneurysm led to hemiathetosis and mild pyra-

Fig. 3. Axial MRI (SE-T1-800/30) after 2 months, showing the
whole mass lesion with hyperintense signal, indicating complete
thrombosis of the aneurysm
Fig. 4. Axial MRI (SE-T2-2100/100) after 7 months, showing organization of the thrombus and reduction in size of both the thrombosed aneurysm and the mass effect

midal signs on the right side. These might be the result of
capsular involvement, together with the involvement of
the basal ganglia on that side, leading to a combined
pyramidal and extrapyramidal syndrome. The fact that
resolution of the s y m p t o m s followed aneurysmal thrombosis suggests the release of capsular and basal ganglionic
compression. This was proved by follow-up :MRI.
Spontaneous intra-aneurysmal thrombosis is a welldocumented phenomenon that has been noted in a b o u t
50% of giant intracranial aneurysms [3, 5, 9, 13]. This
high incidence of thrombus formation within giant intracranial aneurysms is related to a critical ratio between
the size of the aneurysm and that of its neck, below which
intra-aneurysmal thrombosis occurs [18]. This m a y be the
result of eddies forming within the aneurysm. In our patient, the spontaneous thrombosis reflects the natural
course of a giant aneurysm that has not been complicated
by subarachnoid hemorrhage. When such a lesion regresses, release of mass effect and resolution of symptoms
occur. It is, however, advisable to observe the patient and
to do a follow-up at regular intervals with MRI. Such a
patient may be treated without surgery [16].
M R I has greatly facilitated the diagnosis of giant intracranial aneurysms [11]. It can clearly demonstrate the
presence or absence of intra-aneurysmal thrombosis and
the progression or regression of the aneurysm. In our
patient, follow-up M R I showed complete thrombosis of
the aneurysm, and subsequent imaging showed the organization of the thrombus with a reduction in the size of
the aneurysm and a reduction of the mass effect. M R I is
therefore the most helpful tool in the nonsurgical management of such thrombosed giant aneurysms.

Acknowledgement. We would like to express our gratitude to Kathleen Harrison for typing the manuscript.

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