Neurol Med Chir (Tokyo) 41, 611¿614, 2001

Intracerebral Hematoma Due to Ruptured Nontraumatic
Middle Meningeal Artery Aneurysm
—Case Report—
Hitoshi KOBATA, Hideo TANAKA, Yuichi TADA, Kentaro NISHIHARA,
Akira FUJIWARA, and Toshihiko KUROIWA*
Osaka Mishima Critical Care Medical Center, Takatsuki, Osaka;
*Department of Neurosurgery, Osaka Medical College, Takatsuki, Osaka

Abstract
A 77-year-old woman suddenly lost consciousness and presented with right hemiparesis. Computed
tomography showed a large subcortical hematoma in her left frontal lobe associated with subarachnoid
hemorrhage. The first impression was hemorrhage due to a ruptured aneurysm of the middle cerebral or
the internal carotid artery on the left. Left internal carotid angiography showed no aneurysm or vascular anomaly, but back flow of contrast medium into the external carotid artery disclosed two saccular
aneurysms arising from the anterior branch of the left middle meningeal artery (MMA). Emergent surgical intervention confirmed that the hematoma was due to ruptured MMA aneurysm. Nontraumatic
MMA aneurysm should be recognized as a possible causative lesion of intracranial hemorrhage despite
the extremely low incidence. External carotid angiography should be performed in patients with intracranial hemorrhage in whom no vascular cause can be detected in the internal carotid system.
Key words: cerebral angiography,
subarachnoid hemorrhage

intraparenchymal hematoma,

Introduction

ed ruptured MMA aneurysm fortunately.

Case Report

Traumatic pseudoaneurysm of the middle meningeal artery (MMA) is a known cause of intracranial
hemorrhage. Delayed onset of intracranial hemorrhage following previous head injury indicates rupture of a MMA pseudoaneurysm. Nontraumatic
MMA aneurysm is uncommon, and rupture resulting in intracranial hemorrhage is extremely
rare,7,8,15) so might be overlooked especially in
patients without a history of previous head injury.
The aneurysm may not be recognized until the second operation after rebleeding.8) We report an unusual case with a misleading hemorrhagic pattern of
intracerebral hematoma (ICH) and subarachnoid
hemorrhage (SAH), which mimicked a ruptured
aneurysm at the middle cerebral artery (MCA) or the
internal carotid artery (ICA). Urgent left carotid angiography failed to depict an aneurysm of the left internal carotid system; however, overflow of contrast
medium into the external carotid artery demonstratReceived
2001

August 24, 2000;

Accepted

middle meningeal artery aneurysm,

A 77-year-old woman suddenly lost consciousness
and fell down at another hospital on April 24, 1999,
and was transferred to our hospital 30 minutes later.
She had undergone mitral valve replacement
(Carpentier-Edwards bioprosthesis; Baxter, Irvine,
Calif., U.S.A.) for mitral valve regurgitation 18 years
prior to admission, but cardiac insufficiency persisted due to combined mitral stenosis and tricuspid
regurgitation. She had received no anticoagulant
therapy. No head injury was documented within
several weeks before admission. In addition, she had
been taken thyroid hormone for hypothyroidism for
18 years.
On admission, her level of consciousness was 7 (E:
4, V: 1, M: 2) on the Glasgow Coma Scale and 3A on
the Japan Coma Scale. She presented with right
hemiparesis. Her blood pressure was 140/60 mmHg.
External jugular and superficial temporal veins were
engorged on both sides, suggesting severe cardiac
failure. Pansystolic cardiac murmur was audible on

October 3,

611

612

Fig. 1

H. Kobata et al.

Axial computed tomography scans showing
an extensive intraparenchymal hematoma
in the left frontal lobe associated with
subarachnoid hemorrhage and a thin subdural hematoma. The intraparenchymal
hematoma extends to reach the cortical surface.

chest auscultation. She was intubated and evaluated
on an emergency basis.
Computed tomography showed a large subcortical
hematoma that measured 8 × 5 × 6 cm in her left
frontal lobe. The hematoma reached the cortical
surface and was continuous with a thin subdural
hematoma (SDH). Associated SAH was predominant
in the basal cisterns on the left side (Fig. 1). The first
impression was hemorrhage due to a ruptured
aneurysm of the left MCA or ICA. Skull roentgenography detected no fracture. Chest roentgenography exhibited marked cardiomegaly with
cardiothoracic ratio of 76%. Echocardiography
showed severe mitral stenosis and tricuspid regurgitation. No valvular vegetations were detected.
Urgent digital subtraction angiography was
performed. The left selective internal carotid angiography showed displacement of the cerebral vessels, indicating hematoma in the left frontal lobe. No
aneurysm or vascular anomaly was detected in the
internal carotid system. However, overflow of contrast medium into the external carotid artery disclosed two saccular aneurysms, 0.8 cm and 0.3 cm
in diameter, that had arisen from the anterior
branch of the left MMA (Fig. 2). During the angiographic procedure, she developed anisocoria and
lost light reaction. The angiography was discontinued and she underwent emergency surgical intervention.
A right frontotemporal craniotomy was performed. The dural vessels were unusually engorged
and easy to bleed. The thin SDH was evacuated after
dural incision. A small bulge associated with a clot
of blood, consistent in location with the larger
aneurysm of the MMA, was identified in the inner
dural surface opposite to the destroyed cortical surface (Fig. 3). The MMA exposed in the craniotomy

Fig. 2

Anteroposterior (A) and lateral (B) projections of digital subtraction angiograms
demonstrating double saccular aneurysms
arising from the middle meningeal artery
(arrows). Marked displacement of the
cerebral vessels is seen.

Fig. 3

Intraoperative photograph taken after subdural hematoma evacuation demonstrating
the cortical surface destroyed by the hematoma. A small bulge associated with a clot of
blood is seen identified in the inner dural
surface opposite the destroyed cortical surface (arrow).

field was coagulated together with the two
aneurysms arising from the MMA. The ICH was
evacuated via the destroyed cortical surface. The
hematoma cavity and contents were thoroughly inspected to detect any possible vascular anomalies,
but no particular abnormal tissue was identified. No
leptomeningeal anastomotic vessels were detected
on the brain surface. Exploration of the ICA and the
trifurcation of the MCA disclosed no aneurysm.
Intraoperative findings indicated that rupture of an
MMA aneurysm had caused the SAH, SDH, and
ICH.

Neurol Med Chir (Tokyo) 41, December, 2001

Nontraumatic MMA Aneurysm
Table 1

613

Reported cases of nontraumatic middle meningeal artery (MMA) aneurysms

Author (Year)

Age

Sex

Associated disease

Berk (1961)2)
Holland and Thomson (1965)5)
New (1965)10)

73
49
79

F
F
F

Paget's disease, HT
none
Paget's disease, HT

Zingesser et al. (1965)19)
New (1967)11)
Sanchis et al. (1975)14)
Bollati et al. (1980)3)
Takahashi (1980)16)
Jin et al. (1981)6)
Korosue et al. (1988)8)
Ohta et al. (1991)12)
O'Neill et al. (1995)13)
Ushikoshi et al. (1996)17)
Zubkov et al. (1998)20)
Sandin et al. (1999)15)
K äah äar äa (1999)7)
Present case

ND
57
59
50
10
9
66
47
82
69
22
46
58
77

ND
F
F
F
F
M
F
M
F
M
M
M
F
F

ICA occlusion
Paget's disease, HT
dural angioma
none
moyamoya
asthma, MMA angioma
none
cavernous hemangioma of skull
meningioma
HT, PCA occlusion
none
mild HT
dural AVM
chronic heart failure (MS, TR)

Presentation
headache
headache
stroke (ICA
occlusion)
ND
headache
headache
epilepsy
incidental
headache, LOC
headache
incidental
incidental
LOC
SAH
headache
LOC
LOC

Type of
hemorrhage

Remarks

no
EDH
no
ND
no
EDH
old SDH
no
no
recurrent SDH
no
no
ICH, IVH
SAH
ICH
ICH*
ICH, SAH

double aneurysms

multiple aneurysms

double aneurysms

*Hemorrhage due to a ruptured cortical ectatic vein of the dural arteriovenous malformation (AVM). EDH: epidural
hematoma, HT: hypertension, ICA: internal carotid artery, ICH: intracerebral hematoma, IVH: intraventricular hematoma, LOC: loss of consciousness, MS: mitral stenosis, ND: not described, PCA: posterior cerebral artery, SAH:
subarachnoid hemorrhage, SDH: subdural hematoma, TR: tricuspid regurgitation.

Postoperative angiography confirmed the disappearance of both MMA aneurysms. She was
referred to the rehabilitation institute for her motor
aphasia and right hemiparesis.

Discussion
Only 16 cases of nontraumatic MMA aneurysms
have been reported (Table 1).2,3,5–8,10–17,19,20) Seven
presented with intracranial hemorrhage: two cases
of epidural hematoma,5,14) two of SDH,3,8) two of
ICH,7,15,17) and one of SAH.20) Double aneurysms
were found in two cases16,20) and multiple aneurysms
in one.12) The aneurysm was not detected at initial
surgery in one of the cases with SDH, but was
demonstrated by angiography after recurrent
hemorrhage.8) An aneurysm of the anterior communicating artery was suspected in the case with
SAH. The MMA aneurysm was not visualized at the
initial angiography and was only detected at repeat
angiography.20)
In the present case, the pattern of combined ICH
and SAH was similar to that typically seen with ruptured MCA or ICA aneurysm. The patient's condition did not allow full angiographic study, so only
left selective internal carotid angiography was performed on an emergency basis. Fortunately, the contrast medium overflowed into the external carotid
artery to depict the MMA aneurysms. At surgery,
the location of the MMA aneurysm was opposite the

Neurol Med Chir (Tokyo) 41, December, 2001

impaired cortical surface and extended to the intraparenchymal hematoma. Angiographically occult
vascular malformations, which are frequently the
cause of lobar hemorrhage,9,18) were excluded in the
present case.
Dural vascular lesion can cause intracranial
hemorrhage. Rupture of arterialized leptomeningeal
veins results in intracranial hemorrhage in cases
of dural arteriovenous malformation (AVM).1)
However, nontraumatic MMA aneurysm is rare and
could easily be overlooked as a cause of intracranial
hemorrhage. Ruptured MMA aneurysm should be
considered as a possible hemorrhagic origin if ICH
reaches the cortical surface as in the present case.
When standard four-vessel angiography yields negative results, external carotid angiography should be
undertaken.
Necropsy study has found medial defects are common in the meningeal arteries. The elastic lamina
and adventitia often showed increased thickness
over the medial defect. However, the defects were
sometimes thin-walled and separated from the
subarachnoid space only by a thin, loose layer of collagenous tissue.4) Pathological conditions associated
with increased hemodynamic stress of the MMA
could promote aneurysm formation at these thinwalled defects. Histological study has confirmed
that most nontraumatic MMA aneurysms are true
aneurysms like normal cerebral aneurysms.6,8,10–
12,15,20) Lack of media and internal elastic lamina

H. Kobata et al.

614

were present.15,20) Presumably, rupture at the
projected dome into the subarachnoid space causes
SAH, and in the presence of pial adhesion, ICH will
develop, similar to hemorrhage caused by cerebral
aneurysms.
Nontraumatic MMA aneurysms were associated
with Paget's disease,2,10,11) dural angioma or
AVM,6,7,14) cavernous hemangioma of the skull,12)
meningioma,13) moyamoya disease,16) and occlusion
of ICA19) and the posterior cerebral artery.17)
Aneurysm formation in Paget's disease is promoted
by loss of normal support of the MMA due to cranial
softening, increased blood flow in the MMA, and
chronic systemic hypertension.10,11) The MMA is
also exposed to increased blood flow as a feeding
artery of vascular malformations or vascular-rich
tumors. Development of leptomeningeal anastomosis is another cause of MMA overflow associated
with cerebral ischemia. In the present case, whether
chronic venous congestion was related to the formation of MMA aneurysms remains unclear. The reason for aneurysm multiplicity is also unknown. At
present, little is known about the incidence and
natural history of MMA aneurysms.
Rupture of a nontraumatic MMA aneurysm
caused ICH and SAH. This uncommon aneurysm
can cause intracranial hemorrhage of any type. The
external carotid artery should be evaluated if internal carotid angiography does not demonstrate the
source of hemorrhage. Radical surgery is warranted
if a MMA aneurysm is found to be a possible cause
of intracranial hemorrhage. Recognition of this uncommon entity is essential to avoid diagnostic and
therapeutic problems.

7)
8)

9)

10)
11)

12)

13)

14)

15)

16)

17)

References
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2)
3)

4)
5)
6)

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Address reprint requests to: H. Kobata, M.D., Osaka
Mishima Critical Care Medical Center, 11–1 Minami
Akutagawa–cho, Takatsuki, Osaka 569–1124, Japan.
e–mail: neu035＠poh.osaka–med.ac.jp

Neurol Med Chir (Tokyo) 41, December, 2001