IMAGES IN NEUROLOGY

Anosmia in a Giant Anterior
Communicating Artery Aneurysm

REPORT OF A CASE
A 75-year-old man was admitted because of a sudden onset of a right lateral homonymous hemianopia. He
had an 11-year history of a slowly
worsening hyposmia. The results of
serial otorhinological evaluations
had always been normal, and there
was no history of skull trauma.
On admission, the patient’s neurological examination showed a right
lateral superior homonymous quadrantanopia and confirmed a bilateral anosmia (olfactometry). Two
days later, a computed tomographic
scan (Figure 1) revealed an ischemic lesion in the left inferior calcarine region and showed a big frontal
interemispheric hyperdense mass
measuring 45⫻35⫻45 mm, with an
anteroposterior largest diameter. The
lesion was peripherally calcificated
and provoked an important straddle
of ventricular frontal horns, posteriorly pressing against the terminal
plate, anterosuperiorly touching the
falx cerebri, and inferiorly leaning
against the cribriform plate of the ethmoid bone. Cerebral magnetic resonance imaging (Figure 2) followed
by magnetic resonance angiography
(Figure 3) disclosed a completely

patent giant saccular aneurysm of
the anterior communicating artery
(ACA) and clearly showed the close
relationship with the ethmoid plate
and the third ventricle and a dislocation of corpus callosum. Cerebral
angiography and partial resection of
the aneurysm were suggested to the
patient, but he refused both. After 8
months, the results of his clinical examination and cerebral magnetic imaging were unchanged.

ache, dementia, and emotion lability.
The case reported herein is therefore
uncommon in that the only apparent sign was worsening hyposmia; according to our knowledge, only 1 case
of monolateral anosmia has been reported in the literature, and that case
was associated with blindness and diencephalic seizures.3
M. Manconi, MD
Department of Neurological Clinic
Ferrara University
S. Anna Hospital
Corso Giovecca, 203
44100 Ferrara, Italy
(e-mail: manconi18@mailcity.com)
E. Paolino, MD
I. Casetta, MD
E. Granieri, MD
Ferrara

COMMENT
The prevalence rate of cerebral aneurysm is 0.5%; the risk of a rupture is approximately 2% per year
but is dependent on size. According to the Weir classification,1 an aneurysm is considered “giant” when
its largest diameter is greater than 25
mm; only in rare cases can sizes
larger than 35 mm be observed.
Thirty-eight percent of the cerebral
aneurysms are in the ACA, and approximately 90% of them are asymptomatic and must be classified in first
grade of the Hunt-Hess scale.2
When unruptured aneurysms of
the ACA are not silent, the most frequently observed symptoms are visual and endocrine disorders, head-

(REPRINTED) ARCH NEUROL / VOL 58, SEP 2001
1474

REFERENCES
1. Weir B. Intracranial aneurysm and subarachnoid
hemorrhage: an overview. In: Wilkins RH, Rengachary SS, eds. Neurosurgery. Vol 2. New York,
NY: McGraw-Hill Co; 1985:1309.
2. Hunt WE, Hess RM. Surgical risk as related to time
of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968;28:14.
3. Ito H, Shima T, Yamamoto S. Giant anterior communicating artery aneurysm. No Shinkei Geka.
1975;3:171-176.

WWW.ARCHNEUROL.COM

©2001 American Medical Association. All rights reserved.
Downloaded From: http://archneur.jamanetwork.com/ by a NCSU Hunt Library User on 05/11/2015

Figure 1. A computed tomographic scan of the brain shows a left occipital
ischemic lesion and a large hyperdense frontal mass.

Figure 3. A magnetic resonance angiogram shows the aneurysm’s origin
from the anterior communicating artery.

A

B

Figure 2. Sagittal (A) and coronal (B) sections of the brain on magnetic resonance images demonstrate a giant saccular aneurysm and its relationship
to the cribriform plate.

(REPRINTED) ARCH NEUROL / VOL 58, SEP 2001
1475

WWW.ARCHNEUROL.COM

©2001 American Medical Association. All rights reserved.
Downloaded From: http://archneur.jamanetwork.com/ by a NCSU Hunt Library User on 05/11/2015