Case Report Pediatr Neurosurg 2008;44:414–417 DOI: 10.1159/000149911
Received: October 12, 2007 Accepted: February 5, 2008 Published online: August 15, 2008
Chiasmal Cavernoma: A Rare Cause of Acute Visual Loss Improved by Prompt Surgery Hadas Newman a Margalit Nevo b Shlomi Constantini c Shimon Maimon b Anat Kesler a Departments of a Ophthalmology, b Neurosurgery and c Pediatric Neurosurgery, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
Key Words Cavernous malformation ⴢ Cavernoma ⴢ Chiasmal apoplexy ⴢ Optic chiasm ⴢ Visual loss
Abstract We report a 16-year-old healthy boy who presented with sudden loss of vision in both eyes, accompanied by a mild headache. Magnetic resonance imaging showed a chiasmal apoplexy. An urgent craniotomy revealed a cavernous malformation of the chiasm, which was evacuated. There was a subsequent dramatic improvement in bilateral visual acuity and visual field defects. This case report emphasizes the importance of rapid diagnosis and surgery of an anterior visual pathway cavernous malformation. Copyright © 2008 S. Karger AG, Basel
Introduction
Hemorrhage into the structures of the anterior visual pathway (apoplexy of the chiasma or optic nerves) is a rare pathology that can be caused by different pathological processes, among which are cavernous malformations (CMs), arteriovenous malformations, venous malformations and capillary telangiectasis [1, 2]. CMs are benign lesions consisting of clusters of thin-walled immature veins and are the most common of these process© 2008 S. Karger AG, Basel 1016–2291/08/0445–0414$24.50/0 Fax +41 61 306 12 34 E-Mail
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es [2]. Unlike arteriovenous malformations, CMs have a low flow and are angiographically occult. Like arteriovenous malformations, they have no intervening neural tissue [2]. The symptoms of bleeding CMs include seizures, local mass effect with focal neurological deficits and headache; some patients may remain asymptomatic altogether [3]. CMs arising from the optic nerve and chiasm are rare, with only 29 cases having been reported to date. Most of these patients manifested acute visual loss and visual field disturbances [1–4]. We wish to alert the neurosurgical community to the need for urgent surgical intervention, in order to save sight and to prevent permanent blindness.
Case Report A 16-year-old otherwise healthy boy presented with sudden loss of bilateral vision accompanied by a mild headache. On examination, the visual acuity was counting fingers in the right eye and light perception in the left eye. The pupils were equal, with a left relative afferent papillary defect. Ocular motility was normal. An urgent computerized tomography of the brain demonstrated the presence of hemorrhage in the optic chiasm. The patient was immediately transferred to a tertiary medical center, where an urgent magnetic resonance imaging (MRI) scan revealed a chiasmal apoplexy (fig. 1). He underwent a left frontotemporal craniotomy, which revealed a bluish dome in the decussation of the left optic nerve and the chiasm (fig. 2a). The lesion, which was compatible with a CM, was evacuated using a standard meticulous
Anat Kesler Ophthalmology Department, Tel-Aviv Sourasky Medical Center 6 Weizman St. Tel Aviv 64239 (Israel) Tel. +972 3 697 3408, Fax +972 3 697 3867, E-Mail
[email protected]
a
c
b
Fig. 1. MRI of the brain, coronal view, depicting hemorrhage in the left chiasm extending to the left optic nerve and edema on the right side of the chiasm. a Gradient echo T2, a very low signal mass in the left half of the chiasm, depicting hyperacute bleeding. b Gradient echo T2, the hematoma extends to the left optic nerve. c Spin
echo T1, hypointensity and enlargement of the chiasm, more prominent in the left half.
a
b
Fig. 2. CM in the decussation of the left optic nerve and the chiasm. a Before evacuation. b After evacuation.
microsurgical technique (fig. 2b). The visual fields were tested 2 days after surgery and showed a hemianoptic temporal defect in the right eye and a large superior defect in the left eye, with only a lower field remnant (fig. 3a, b). The 1-month postoperative follow-up examination revealed that his visual acuity recovered to 20/20 in the right eye and to 1/18 in the left eye. Color vision was 10/10 in the right eye and 0 in the left eye. There was a left relative afferent papillary defect. Both optic discs showed temporal pallor, more significant in the left eye. There was an improvement of the visual field defects in both eyes at 1 month postoperatively (fig. 3c, d).
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Discussion
CMs of the anterior visual pathway are extremely rare [1–4]. Most patients present in their third or fourth decade with an apoplectic event, but there have been several cases of an expansile mass effect. The symptoms include acute chiasmatic syndrome consisting of acute visual loss in one or both eyes, retrobulbar pain and headache, and visual field loss. Another form is a progressive visual loss [1–4]. Pediatr Neurosurg 2008;44:414–417
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a
b
c
d
Fig. 3. Kinetic (Goldmann) visual fields. Second postoperative day, a large superior defect in the left eye, with only a lower field remnant (a) and a hemianoptic temporal defect in the right eye (b). One month after the operation, improvement of the visual field defects in both the left (c) and right (d) eyes.
As in the presented case, the diagnosis is not apparent until surgery is performed. Routine angiography does not reveal the vascular nature of the lesion. MRI is the preferred imaging modality, demonstrating acute and chronic hemorrhage [4]. The MRI findings include central focus of methemoglobin, peripheral rim of hemosiderin, adjacent focus of acute or subacute hemorrhage and minimal or no enhancement with gadolinium. Pathological evaluation of a tissue specimen from the lesion reveals thin-walled vascular spaces with no intervening neural tissue [5].
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Most recently reported cases of anterior visual pathway CMs have been treated surgically [2]. A gliotic interphase between the malformation and normal neural tissue provides a plane of cleavage for dissection, which permits total excision without causing new deficits [6]. Expectant management is indicated when the presenting symptoms are seizures with minimal or stable visual loss. There are no reports of long-term postsurgical follow-up, but complete resection of the lesion is thought to be curative, due to decompression of the hematoma. Most reported cases, which have undergone surgery, improved or remained unchanged during short-term follow-up [2]. Newman /Nevo /Constantini /Maimon / Kesler
Conclusion
The current case report emphasizes the importance of a rapid diagnosis and surgery of an anterior visual pathway CM. Even blind eyes may improve remarkably if surgical decompression of the optic apparatus is undertaken
References
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early. The level of awareness of chiasmal apoplexy and reversibility of loss of vision needs to be increased among the medical community, especially ophthalmologists and general practitioners, so that timely neurosurgical intervention can be performed.
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