Child’s Brain 3: 169-179 (1977) Spontaneous Occlusion of an Intracranial Arteriovenous Malformation 1. Pascual-C astroviejo ; J. I. P ascual-P ascual; M. G. B lazquez and V. L opez -M artin Service of Neurology (Head: Dr. I. P ascual-C astroviejo), Clínica Infantil 'La Paz’, Madrid Key Words. Arteriovenous malformation (AVM) • Thrombosis of the intracrani­ al AVM • Arachnoid cysts ■External hydrocephalus • Infantile hemiparesis • In­ tracranial calcification • Cranial asymmetry Treatment of arteriovenous malformations (AVM) of the central nerv­ ous system (CNS) has undergone many changes. They have been treated by radiotherapy, extirpation, isolation of the circulatory system by means of tying off the extracranial portion of the carotid artery which gives rise to the malformation or by positioning of clips in the artery itself and, fi­ nally, by direct thrombosis of the malformation by means of the use of several diverse substances or the use of a small rounded object placed in the principal arterial branch or branches which carry most or all of the blood to the AVM. There are few cases described in medical literature where a complete or partial spontaneous occlusion of the malformation is referred to. The following case, which we observed and which presented an AVM in the central region of the encephalon associated with an arachnoid cyst Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Abstract. The case of a 2-month-old girl is described in whom an arteriovenous malformation (AVM) was observed in the paramedial region of the right cerebral hemisphere associated with an arachnoid cyst in the right fronto-parieto-temporo-occipital region. The only treatment was evacuation of the arachnoid cyst by trephination. When the child was 3 years old, images of the AVM were not found although all the intracranial vessels were angiographically explored. It is con­ sidered that the reduced pressure in the right cranial cavity due to the drainage of the arachnoid cyst may contribute to the occlusion of the AVM by causing a slight displacement of the intracranial structures towards the side of the drained cyst. 170 P ascual-C astrovu-jo /P ascual-P ascuai Bi .azquez /L opez -M artin Fig. 1. 2 months old. Pneumoencephalography. Great forward and downward displacement of the right lateral ventricle. The right intracranial cavity is much larger than the left. of the right cerebral hemisphere, showed occlusion of the AVM following the evacuation of the arachnoid cyst. M. J. R. T., female, 5 years old. The child was first seen by us because of macrocephalus and left hemiparesis when she was 2 months old. She presented pyramidal signs on the left side and her cephalic circumference was 44 cm. The EEG showed a focus of slow waves throughout the entire Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Case History Spontaneous Occlusion of an Intracranial Arteriovenous Malformation 171 right cerebral hemisphere. Cranial radiographs showed a greater develop­ ment of the right cranial cavity and a finely speckled oval (2X1.5 cm) calcification situated in the medial region of the cranial cavity. Pneu­ moencephalography showed a large displacement of both lateral ventri­ cles and of the 3rd ventricle towards the left; the left lateral ventricle (LLV) appeared dilated and the right lateral ventricle (RLV) was col­ lapsed and downwardly displaced (fig. I): calcification was seen outside of the RLV carotid and right vertebral angiography, performed by brachi­ al injection, showed the following: ‘a large avascular zone in the right fronto-parieto-occipito-temporal region which displaces almost all the vessels of the right hemisphere toward the anterior frontal region; a large, oval AVM which extends from the right suprasellar region towards the be- Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Fig. 2. 2 months old. Right vertebral and carotid angiography by means of brachial injection. Large AVM which is repleted by an undulating artery which originates from the internal carotid artery (->) and by a second smaller artery which originates from the posterior cerebral artery and which appears to correspond to the lateral choroid artery (->-). An avascular zone is seen in the fronto-parieto-temporal region in which a large arachnoid cyst is found. Forward displacement of the anterior and middle cerebral arteries. 172 P ascual-C astroviejo/P ascuai -P ascual/B lazquez/L opez -M artin ginning of the straight sinus following a right parasaggital plane’ (fig. 2, 3). The afferent branches of this AVM originate from a branch of the inter­ nal carotid artery which appears to be the anterior choroidal artery, showing an enlarged and undulating appearance, and from another en­ larged artery which originates from the posterior cerebral artery appear­ ing to be the posterolateral choroid artery. Drainage of the AVM, which occurs by way of the straight sinus, itself also enlarged, is quite slow. The superior sagittal sinus has been displaced to the left, with one transverse sinus, the left being quite short and the right one being downwardly dis­ placed (fig. 4). The arachnoid cyst was evacuated in the Neurosurgery Service. 14 months later the intracranial calcification showed the same di- Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Fig. 3. A-P projection of the same exploration. The AVM occupies the left paramedial region of the intracranial cavity. Spontaneous Occlusion of an Intracranial Arteriovenous Malformation 173 mensions, but had a greater density and was situated 1 cm higher and more towards the right than in the earlier radiographs (at 2 months of age). Cardiac studies were normal. The studies were repeated when she was 3 years old. The following observations were noted: a discreet macrocephalus (cephalic circumference: 58 cm), left hemiparesis with deformities of the limbs of the same side, divergent strabismus in the right eye, bilat­ eral pallor of the optic papilla, initiation of step-taking but falling easily, evident mental retardation. The EEG showed an irritative focus in the Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Fig. 4. Venous phase of the same case. The AVM drains into the confluence of the sinuses. Significant displacement of the superior longitudinal sinus towards the left, inward displacement of the peripheral veins of the right hemisphere and down­ ward and inward displacement of the right lateral sinus. Asymmetry of the lateral sinuses. 174 P ascual-C astroviejo/P ascuai -P ascuai./B i .azquf.z /L opez -M artin right hemisphere. Radiographs of the cranium showed a similar position­ ing of the calcified mass and a large reduction of the degree of cranial asymmetry. Pneumoencephalography showed images similar to those of the previous examination. Right vertebral and carotid angiography (brachial injection) clearly showed all the intracranial vessels, arteries, veins and venous sinuses which presented normal morphology and course, although images of large chronic subdural collections were seen in the right side of the cranial cavity (fig. 5. 6). The image of the AVM which had been seen in the first angiographic examination had completely disappeared. The calcification was situated in the posterior region and to the right (paramedially) to the vein of Galen. Left carotid angiography was completely normal except for a slight displacement of the anterior ce­ rebral artery towards the left (fig. 7). Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Fig. 5. 3 years of age. Right vertebral and carotid angiography by brachial injec­ tion. The image of the AVM has completely disappeared. Intracranial calcification may be seen (-»-). Spontaneous Occlusion of an Intracranial Arteriovenous Malformation 175 Fig. 6. 3 years of age. A-P projection of the right carotid and vertebral angiog­ raphy. A great inward displacement of the middle cerebral artery is observed along with a very large subdural collection. Image of the AVM does not exist. The chronic subdural collection was evacuated, and at the present mo­ ment (5 years of age) the child shows a IQ of 79°/o (Terman's test) and a significant left hemiparesis. although she is able to walk with some agility. Intracranial AVM are sometimes seen with particular clinical charac­ teristics, such as generalized or focal convulsive crises, sudden hemor­ rhages which may be recurrent at times, motor and/or sensory deficien- Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Discussion 176 P ascuai.-C astroviejo/P ascual-P ascuai./B i .azquez/L opez -M artin cies, signs of intracranial hypertension, headache and cardiac failure being among the most important characteristics. The clinical alterations are due sometimes to direct action of the AVM or to the vascular defi­ ciencies in certain cerebral regions which may have their origin in the dis­ placement of certain principal vessels towards the arteriovenous fistula. In our particular case, it seems that the large arachnoid cyst, compressing the right cerebral hemisphere from before birth, was the cause of the pyr­ amidal signs in the left side of the body and the cause of the large dis­ placement of all the intracranial structures towards the left. These facts are well observed with pneumoencephalography and angiography. Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Fig. 7. 3 years of age. Left carotid angiography. The anterior cerebral artery shows an evident displacement to the left. There is no sign of the AVM. The calcifi­ cation appears in the right paramedial line <->-). 177 The occlusion of the malformation due to organized hematomas which bring about compression and thrombosis of the malformation have been seen during surgery and in autopsies [4, 10-12J. Regressive since changes of the AVM following the ligature of the car­ otid artery or the principal nutritive arteries and radiotherapy have been occasionally described [4, 8, 11, 12]. Direct thrombosis of the AVM injecting various substances or artifacts into the more important branches of the angioma preceded by supraselective angiography is becoming more perfected with use [2, 3, 5, 15]. Partial or complete spontaneous occlusion has only been rarely de­ scribed. N orlen [11] observed an AVM in the angiography of a patient but during surgery a much larger malformation was found leading to the conclusion that a partial spontaneous thrombosis had occurred previous to the angiographic study. Svien and Peserico [14] described the case of a 46-year-old woman who showed a large AVM at the origin of the left sylvian artery, which disappeared 4 years later without treatment. H ook and J ohnson [6] de­ scribed a patient with an AVM in the left fronto-parietal region, which disappeared 21 years later. A gee and G reer [1] presented a case of a 37-year-old patient with an AVM in the vein of Galen and hydrocephalus which was treated by drainage of the CSF. Kelly et al. [7] described the decrease in size of the AVM in one of their cases. K ushner and A lexan­ der [9] presented the case of a 46-year-old patient with an AVM at the origin of the right middle cerebral artery, which spontaneously disap­ peared almost completely 7 years later, with only a small angiomatous mass seen during the venous phases. Sukoff et al. [13] published the findings of a case of a 59-year-old patient with an AVM in the right par­ ietal region which filled by means of an anomalous middle cerebral artery. Eight months later it had almost completely disappeared without treat­ ment. Our case may be considered as an AVM situated in the most internal hemispheric region which is drained by the straight sinus. It had visible calcification from the first few months after birth. The calcification only corresponded to a small portion of the AVM, the posterior and lateral portion, at first being found in the midline, and later appearing lateralized towards the right and with increased density after the suprahemispheric arachnoid cyst of the right cranial cavity was evacuated. It seems likely that this calcification, although it did not fill with contrast medium during the angiographic studies, constituted part of the AVM, forming the most Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 7/10/2017 3:53:58 AM Spontaneous Occlusion of an Intracranial Arteriovenous Malformation 178 P ascual-C asi-roviejo /P ascual-P ascual/B lazquez/L opez -M artin posterior and lateral portions. A similar finding was described by K u s h ner and A lexander [9]. It is possible that in our case, the drainage of the liquid of the arach­ noid cyst, as in the case of A gee and G reer [1], by the use of a drainage valve in the lateral ventricle due to the presence of hydrocephalus, may bring about a change, however slight, of the cerebral structures, which be­ come lateralized toward the side in which the intracranial pressure has been reduced. This may contribute to the afferent and efferent vessels of the AVM being found in an unfavorable position, hemodynamically, and therefore they spontaneously occlude with greater ease. Our case is unique, being the only one described which is associated with an arach­ noid cyst and also it is the youngest patient in whom a spontaneous occlu­ sion of an AVM has been described. 1 A gee , O. F. and G reer . M.: Anormalous cephalic venous drainage in associa­ tion with aneurysm of the great vein of Galen. Radiology 88: 725-729 (1967). 2 D ebrun , G.; L acour. P.; C aron, J. 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