Choroid Plexus Arteriovenous

Malformations

Yoshio MIYASAKA, Kenzoh YADA, Takashi OHWADA*, Seiji MORII, Takao KITAHARA*, Akira KURATA and Ryusui TANAKA Departments

of Neurosurgery and *Critical Care Medicine, Kitasato School of Medicine, Sagamihara, Kanagawa

University

Abstract Among 24 arteriovenous malformations (AVMs) involving the choroid plexus, 11 were plexal type AVMs predominantly located in the choroid plexus of the lateral ventricle, and 13 were parenchy mal type AVMs mainly situated in the paraventricular cerebral parenchyma. 83% of all AVMs in volved both the choroid plexus and the paraventricular cerebral parenchyma. Most cases presented with intracranial hemorrhage, particularly intraventricular hemorrhage. The most serious surgical problem was a small residual nidus unrecognized at the initial operation causing postoperative hemorrhage. Five parenchymal type AVMs presented residual niduses in the choroid plexus, causing death in two cases. Two plexal type AVMs resulted in residual AVMs supplied by the cisternal seg ment of the anterior choroidal artery, situated in the medial temporal lobe. To prevent postopera tive hemorrhage from a small residual nidus, immediate postoperative angiography while the pa tient is still under general anesthesia should be performed to identify any residual nidus. Key words:

arteriovenous

intraventricular

hemorrhage,

malformation, surgical

lateral treatment,

Introduction

ventricle,

choroid

postoperative

plexus,

complication

Clinical

Materials

and

Methods

Arteriovenous malformations (AVMs) involving the This study examined surgical excisions of choroid choroid plexus in the lateral ventricle are classified as plexus AVM in 10 females and 14 males, ranging in choroid plexus AVMs, but have also been reported age from 8 to 47 years (mean, 27 years). All AVMs as "trigonal AVMs,"') "anterior choroidal artery were verified histologically. AVMs, ))4,12)"intraventricular AVMs,"91 "AVMs of The exact location of each malformation was the lateral ventricle,"") "juxtapeduncular AVMs, "2' determined by angiography and intraoperative ex "subtrigonal AVMs ,"') "AVMs of the medial tem amination. Only four AVMs were located solely in the choroid plexus. Twenty AVMs (83%) involved poral lobe,"" "paraventricular AVMs,i10' "AVMs of the medial cerebral hemisphere and the limbic both the choroid plexus and the cerebral paren system, "''g' and "AVMs of the corpus chyma. The cases were classified according to the callosum."14'15) predominant AVM location. Eleven plexal type Most discussion has focused on the various AVMs were predominantly located in the choroid surgical approaches to such lesions. 1-3,5,7-12,14,15) plexus of the temporal horn and/or the trigone of However, no large series of choroid plexus AVMs the lateral ventricle (Fig. 1 left). Thirteen paren has been systematically classified into plexal and chymal type AVMs were mainly situated in the parenchymal types. The present study discusses the paraventricular cerebral parenchyma (Fig. 1 right). clinical features and surgical indications and prob An AVM was defined as "large" when the max lems for these types of choroid plexus AVM. imum diameter of the nidus was greater than 5 cm, "medium"

when between

when less than 3 cm. Received 1991

April

23,

1991;

Accepted

September

19,

3 and 5 cm

, and "small"

Fig. I

Schematic drawings, representing the locations of 11 plexal type (left) and 13 parenchymal type AVMs (right). ' The dotted area represents the plexal malformation

Illustrative

in each case.

Case

Reports

Case 1 (plexal type): An 8-year-old girl suffered an in traventricular hemorrhage. On admission she was stuporous, but became fully alert 10 days later. Left carotid angiograms revealed a small AVM extending from the temporal horn to the trigone, supplied by the anterior choroidal artery, and drained by the basal vein (Fig. 2 upper). Forty days postictus, the AVM was excised via a left temporal craniotomy. The left trigone was ap proached through an incision in the middle temporal gyrus. A small cluster of abnormal vessels was re moved from the trigone. Postoperative angiograms, however, demonstrated a residual nidus in the tem poral horn. Craniotomy was repeated by the same ap proach. The plexal segment of the anterior choroidal artery was sectioned where it passed along the choroidal fissure in the temporal horn. The residual AVM-like lesion and the choroid plexus in the tem poral horn were totally removed. Unexpectedly, postoperative angiograms revealed a persistent residual nidus (Fig. 2 lower). Although the plexal nidus had been completely removed, the paren chymal part still remained, fed by the cisternal seg ment of the anterior choroidal artery. A third opera tion resected the medial wall of the temporal horn and part of the hippocampus including a small cluster of abnormal vessels. The basal vein, the posterior cerebral artery, and the cerebral peduncle were inspected. Angiograms demonstrated total removal. Her postoperative course was uneventful except for a right upper-quadrant hemianopsia. Case 2 (parenchymal type): A 23-year-old female

Fig. 2

Case 1. upper: Preoperative lateral left carotid angiograms, early (left) and late (right) arterial phases, demonstrating an AVM (ar row) in the choroid plexus of the temporal horn extending to the trigone of the lateral ven tricle. The AVM was fed by the anterior choroidal artery (closed arrowheads) and drained by the basal vein (open arrowheads). lower: Lateral left carotid angiogram after second operation, showing complete absence of AVM in the choroid plexus. However, a residual nidus is visualized in the medial tem poral lobe (double arrow), fed by the cisternal segment of the anterior choroidal artery (closed arrowhead) and drained by the basal vein (open arrowhead).

presented with a 14-year history of frequent visual seizures. Neurological examination on admission was normal. Right carotid and vertebral angiograms revealed a large parietotemporo-occipital AVM sup plied by enlarged branches of the middle cerebral and posterior cerebral arteries (Fig. 3). No malforma tion fed by the anterior choroidal artery was visible. Postcontrast computed tomographic (CT) scans also demonstrated the AVM but no intraventricular nidus (Fig. 4). Right parietotemporo-occipital craniotomy dem

Postoperatively, she remained comatose, and died from increased intracranial pressure 7 days later. No autopsy was undertaken. Results

Fig. 3

Case

2.

Preoperative

grams, lateral (left) and views, demonstrating a occipital AVM supplied of the middle cerebral tion fed by the anterior rows) is visible.

right

carotid

angio

anteroposterior (right) large parietotemporo by enlarged branches artery. No malforma choroidal artery (ar

The initial symptoms were subarachnoid hemor rhage in 22 of 24 cases (Table 1). CT scans demonstrated intraventricular hemorrhage in 20 of the 22 cases with hemorrhagic episodes. All but one of the plexal type AVMs were small, while all paren chymal type AVMs were medium or large. Plexal type AVMs were fed by the anterior choroidal and the posterior choroidal arteries (Figs. 2 upper and 5, Table 2). Parenchymal type AVMs were mainly fed

Table

1

Clinical

data

for 24 choroid

plexus

AVM

pa

tients

Fig. 4

Case 2. showing lobe. not

The

Preoperative postcontrast CT scans, an AVM in the right parieto-occipital intraventricular

apparently

part

of the

nidus

is

documented.

onstrated a diffuse nidus throughout the parieto temporo-occipital lobe. Differentiation between the malformation and surrounding normal brain tissue was difficult. Therefore, a right occipital lobectomy was finally inevitable. The ventricular wall was not opened for inspection of the choroid plexus AVM in the lateral ventricle. Eight hours postoperatively, her consciousness deteriorated acutely, and symp toms of brain herniation appeared. A CT scan showed massive intraventricular and intracerebral hemorrhage. Emergency reoperation demonstrated abnormal bleeding from small abnormal vessels in the choroid plexus of the posterior horn, which were removed. The excised lesion was verified histologically

as an AVM.

Fig. 5

A 40-year-old female suffering from intraven tricular hemorrhage with small thalamic hematoma. Preoperative superselective angio grams, lateral (left) and anteroposterior views (right), demonstrating a trigonal AVM (plexal type) supplied by the left lateral posterior choroidal artery and drained by the internal cerebral vein.

by enlarged cortical arteries, but the small part of the nidus in the choroid plexus was supplied by the anterior choroidal and/or the posterior choroidal arteries (Fig. 3, Table 2). Magnetic resonance (MR) imaging (Resona, 0.5 T),

Table

3

Clinical

data

of seven

patients

with

residual

AVM

performed for the last 10 cases, was very useful for the identification of the major part of the AVM. In addition, smaller parenchymal involvement in the plexal type (Fig. 6), or minor intraventricular exten sion in the parenchymal type was demonstrated in four of the 10 cases. All AVMs were removed micro surgically. The middle temporal gyrus approach or the paramedian transcortical or transventricular approach via the parieto-occipital junction type. The interhemispheric

Table

2

Feeding

arteries

choroid

plexus

was used for the plexal or transcortical approach

and AVM

draining

veins

in 24

cases

was used for the parenchymal type. Two plexal type and five parenchymal type presented small residual AVMs after the initial opera tion (Table 3). Although the postoperative blood pressure was maintained at 100-120 mmHg systolic, the residual lesions caused postoperative hemorrhage in four of five parenchymal type cases. In two of these, hemorrhage occurred within 24 hours of opera tion. The plexal type cases had small residual niduses extending from the medial wall of the temporal horn to the hippocampus and fed by the cisternal segment of the anterior choroidal artery (Fig. 2 lower). The niduses were totally removed at reoperation by open ing the medial wall of the temporal horn. The paren chymal type cases had residual AVMs in the choroid plexus supplied by the plexal segment of the anterior choroidal or the posterior choroidal artery. The residual AVMs were completely removed at re operation by opening the ventricular wall from the cerebral parenchymal side. The surgical results, assessed by the Glasgow Out come Scale,' were good recovery in 10 (91%) plexal type cases and nine (69%) parenchymal type cases, or 79% overall. Preoperative neurological deficits continued postoperatively in three cases with moderate disability. Two parenchymal type AVM cases died from postoperative hemorrhage caused by a residual nidus. Discussion

Fig. 6

Same case as in Fig. 5. Preoperative coronal TI-weighted (left; TR 400/TE 25 msec) and T2 weighted MR images (right; TR 2060/TE 60 msec) 3 weeks after hemorrhage, showing an AVM extending from the trigone to the thalamus (arrow), feeding artery (double ar row), draining vein (open arrowhead), and old thalamic hematoma (closed arrowhead).

AVMs within or near the ventricular system frequent ly hemorrhage. 1-3,5.7.5,10-12.14,1;) In this series, all plexal type and 11 of 13 parenchymal type cases presented with intracranial hemorrhage. In particular, intraven tricular hemorrhage on the CT scans is characteristic of choroid plexus AVMs (Table 1). 83% of all choroid plexus AVMs involved both

the choroid

plexus and the paraventricular

cerebral

parenchyma. This is important when planning surgery for all choroid plexus AVMs. An AVM located only in the choroid plexus of the lateral ventricle is relatively straightforward to re move. 5) However, we encountered surgical problems in two cases with a small residual AVM extending from the medial wall of the temporal horn to the hip pocampus (Fig. 2 lower, Table 3). The main location of these AVMs was the choroid plexus of the tem poral horn or the trigone, but anatomically resem bled "AVMs of the medial temporal lobe' 5) and "juxtapeduncular angioma .i2' U10' described two cases of intraventricular AVMs where most of the lesion was located in the cerebrospinal fluid space, but extended to the paraventricular white matter. Batjer and Samson') described a patient with a trig onal AVM projecting inferiorly from the floor of the trigone, involving the cortex of the parahippo campal gyrus. Such residual niduses of the plexal type are located near functionally important ana tomical structures, such as the cerebral peduncle, the lateral geniculate body, and the posterior cerebral artery. Exploratory inspection of the medial tempo ral lobe in the region of the temporal horn or the trigone involves considerable hazard. Preoperative angiography cannot indicate a lesion supplied by the cisternal segment, so immediate postoperative angiography is necessary (Fig. 2 lower). Five parenchymal type cases presented small residual AVMs in the choroid plexus (Table 3). Unlike the plexal type AVMs, all parenchymal type were medium to large, and predominantly supplied through enlarged cortical arteries (Tables 1 and 2). The large parenchymal portion of the AVM some times conceals a small intraventricular nidus (Figs. 3 and 4). Paraventricular AVMs, such as AVMs in the cerebral hemispheres, corpus callosum, and basal ganglia, may extend to the subependymal layer and the ventricular system. 2,5,7,8,12"4,15) A serious complica tion of parenchymal type cases was postoperative hemorrhage caused by intraventricular residual AVM (Table 3). During the initial operation, the ven tricular wall should routinely be opened from the cerebral parenchymal side to inspect the choroid plexus of the lateral ventricle, particularly where in traventricular hemorrhage is present. Technical advances in MR imaging and superse lective angiography will be invaluable in the future to preoperatively demonstrate the precise relation ship between the parenchymal and plexal involve ment in choroid plexus AVMs (Figs. 5 and 6). Yasargil13' reported that 24 of 414 patients (5.8%) demonstrated a residual AVM after first operation,

and immediate postoperative bleeding occurred in 12, six of whom died. Residual AVM occurred in 16 of 127 cases (13%) at our hospital. Nine cases devel oped massive postoperative hemorrhage from the residual lesions necessitating emergency craniotomy. In five of these, the hemorrhage occurred within 24 hours of surgery. Residual niduses were found in seven of 24 cases (29%) of choroid plexus AVMs and in nine of 103 cases (9%) with other AVMs. Therefore, choroid plexus AVMs are associated with a higher incidence of residual niduses than other AVMs. Since April, 1988, our policy has been to perform immediate postoperative angiography under anesthesia to confirm complete removal of the AVM. Patients demonstrating residual AVMs are taken di rectly back to the operating room for complete removal. Follow-up angiography is carried out, generally in the first month and the first year after surgery. Since this policy was begun, no patient has suffered postoperative hemorrhage from a residual AVM. Complete removal requires a different procedure for each type of choroid plexus AVM. Immediate postoperative angiography is the most reliable and the least hazardous method for preventing postoperative bleeding from residual AVMs. References 1)

2)

3)

4)

5) 6)

7)

8)

9)

Batjer H, Samson D: Surgical approaches to trigonal arteriovenous malformations. J Neurosurg 67: 511 517, 1987 Da Pian R, Pasqualin A, Scienza R: Microsurgical treatment of juxtapeduncular angiomas. Surg Neurol 17: 16-29, 1982 Drake CG: Cerebral arteriovenous malformations: Considerations for and experience with surgical treat ment in 166 cases. Clin Neurosurg 26: 145-208, 1979 Fujita K, Matsumoto S: Anterior choroidal artery arteriovenous malformation: Its clinical manifesta tions and surgical treatment. Surg Neurol 21: 347 352, 1984 Hero RC: Arteriovenous malformations of the medial temporal lobe. J Neurosurg 56: 44-52, 1982 Jennett B, Bond M: Assessment of outcome after severe brain damage: A practical scale. Lancet 1: 480-484, 1975 Solomon RA, Stein BM: Surgical management of arteriovenous malformations that follow the ten torial ring. Neurosurgery 18: 708-715, 1986 Stein BM: Arteriovenous malformations of the medial cerebral hemisphere and the limbic system. J Neurosurg 60: 23-31, 1984 Sugita K: Arteriovenous malformation, in Sugita K (ed):

Microneurosurgical

Atlas.

Berlin,

Springer

Verlag,

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1985,

pp 137-183

U HS: Microsurgical excision of paraventricular arteriovenous malformations. Neurosurgery 16: 293 303, 1985 Waga S, Shimosaka S, Kojima T: Arteriovenous malformations of the lateral ventricle. J Neurosurg 63: 185-192, 1985 Wilson CB, Martin NA: Deep supratentorial arteriovenous malformations, in Wilson CB, Stein BM (eds): Intracranial Arteriovenous Malforma tions. Baltimore, Williams & Wilkins, 1984, pp 184 208 Yasargil MG: Residual AVM and postoperative course, in Yasargil MG (ed): Microneurosurgery, vol IIIB. New York, Thieme, 1988, pp 376-378

14)

15)

Yasargil MG, Jain KK, Antic J, Laciga R: Arteriovenous malformations of the splenium of the corpus callosum. Surg Neurol 5: 5-14, 1976 Yasargil MG, Jain KK, Antic J, Laciga R, Kletter G: Arteriovenous malformations of the anterior and the middle portions of the corpus callosum: Microsurgical treatment. Surg Neurol 5: 67-80, 1976

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Choroid plexus arteriovenous malformations.

Among 24 arteriovenous malformations (AVMs) involving the choroid plexus, 11 were plexal type AVMs predominantly located in the choroid plexus of the ...
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