Detection of cryptic vascular malformations by computerized tomography. Report of two cases

Radiology and imaging for cavernous malformations

Cavernous malformations are low-flow vascular malformations that are histologically characterized by the lack of mural elements of mature vascular structures and intervening parenchymal neural tissue. They are often clinically quiescent, and may grow, bleed, and regress, but can also manifest clinically as neurologic deficits or seizures in the setting of an acute hemorrhage. The low-flow nature of cavernous malformations renders them inherently occult on cerebral angiography. Magnetic resonance imaging has become the mainstay imaging modality in evaluating cavernous malformations, producing characteristic imaging features that usually provide a straightforward diagnosis. Features on magnetic resonance imaging include a reticulated pattern of mixed hyper- and hypointensity on T1- and T2-weighted imaging, with a characteristic hypointense rim best appreciated on T2-weighted imaging or gradient-echo sequences. Contrast enhancement is useful for revealing coexisting developmental venous anomalies that are frequently associated with sporadic cavernous malformations, and may further support the diagnosis. Susceptibility-weighted imaging is highly sensitive for cavernous malformations and accompanying developmental venous anomalies, and is superior to gradient-echo sequences in screening for multifocal, familial cavernous malformations.

Cavernous Angioma of the Cerebral Aqueduct

BACKGROUND

Among the rare intraventricular cavernomas, purely intra-aqueductal cavernomas are exceptionally rare.

CASE DESCRIPTION

A 62-year-old patient presented with progressive headache, memory loss, gait instability, and urinary incontinence. Magnetic resonance imaging showed the presence of a mass lesion located in the lumen of the cerebral aqueduct, associated with triventricular hydrocephalus.

CONCLUSIONS

We discuss the rationale that led us to treat hydrocephalus with neuroendoscopy, which offered the possibility to directly inspect the intra-aqueductal lesion, make the diagnosis of cavernoma, and treat symptoms resulting from hydrocephalus without increasing the risk of bleeding.

[Cavernoma of the fourth ventricle: report of a case and review of the literature]

Le siège intraventriculaire est une localisation rare des cavernomes de l'encéphale. Le quatrième ventricule est le moins concerné de toutes les localisations. Nous rapportons le cas d'une patiente âgée de 52 ans qui présente depuis 12 mois un syndrome d'hypertension intracrânienne et trouble de l’équilibre. Elle s'est présentée aux urgences avec un GCS à 14, nuque subraide, un syndrome cérébelleux statokinétique avec une acuité visuelle basse et un oedeme papillaire bilatéral. Une TDM cérébrale réalisée aux urgences a objectivé un hématome du 4ème ventricule avec hydrocéphalie active triventriculaire. Une dérivation ventriculaire interne a été réalisée en urgence avec une bonne évolution clinique post opératoire. Le bilan a été complété par une IRM cérébrale objectivant un processus du quatrième ventricule évoquant un cavernome. Un abord direct a été réalisé permettant une exérèse totale du cavernome siégeant au sein du quatrième ventricule. L'anatomo-pathologie a confirmée le diagnostic. A notre connaissance, il s'agit du 13^ème cas rapporté dans la littérature. Les cavernomes intraventriculaires représentent 2,5-10% de tous les cavernomes dont 9% est au niveau 4ème ventricule. Les patients sont souvent admis aux urgences suite au saignement de cette malformation angiomateuse. Le diagnostic est rendu accessible par les différentes séquences de l'IRM. Le traitement est souvent chirurgical vu le risque de resaignement. Le pronostic dépend de l’état initial du patient et de l'infiltration du plancher du quatrième ventricule.

Intraventricular cerebral cavernomas: a series of 12 patients and review of the literature

Object

Intraventricular cavernomas (IVCs) occur in only 2–10% of patients with cerebral cavernomas. Reports concerning IVC are scarce and are limited mostly to sporadic case reports. In this paper, the authors present a series of 12 patients with IVCs that were treated at a single neurosurgical department. In addition, the authors reviewed the literature.

Methods

All clinical data were analyzed retrospectively. Follow-up questionnaires were sent to all patients. Outcome was assessed using the Glasgow Outcome Scale. The authors also conducted a PubMed search and found 77 cases of IVC.

Results

The patients' median age was 47 years, and the male/female ratio was 2:1. A cavernoma occurred in the lateral ventricle in 6 patients, in another 5 it was in the fourth ventricle, and 1 had a lesion in the third ventricle. Almost all patients presented with acute headache on admission and in more than half, the symptoms were related to cavernoma bleeding. In total, 8 rebleedings occurred in 5 patients during a median of 0.4 years. Three patients with a cavernoma of the fourth ventricle presented with a cranial nerve deficit. In 8 cases, a cavernoma was surgically treated an average of 1.3 years after the diagnosis. Only 1 patient underwent surgery in the acute phase after a major intraventricular/intracerebral hemorrhage. The median follow-up time was 2 years. No patient was lost to follow-up, and no patient died. In total, on follow-up 9 patients improved and 3 had a persistent neurological deficit, of which 2 existed before surgery.

Conclusions

In the present series, the IVCs had a high tendency for rehemorrhage. Surgery is advocated when hemorrhages are frequent, and the mass effect causes progressive neurological deficits. Microsurgical removal of the IVC is safe, but in the fourth ventricle it can carry increased risk for cranial nerve deficits.

Role of superselective angiography in the detection and endovascular treatment of ruptured occult arteriovenous malformations

SUMMARY

Three cases of occult micro-arteriovenous malformations not identified by cerebral angiography or other imaging modalities were detected by superselective angiography. The first case had a small intracerebral hemorrhage in the superior colliculus, the second had a perimesencephalic subarachnoid hemorrhage, and the third presented with intracerebral hemorrhage combined with massive intraventricular hematoma. While repeated selective cerebral angiography (four-vessel study) was negative, superselective angiography clearly demonstrated each lesion with small early venous filling in accordance with the location of hematoma. Successful superselective embolization with polyvinyl alcohol particles was performed in each micro-arteriovenous malformation by flow-guided microcatheter without postoperative complications. Our experience suggests that superselective angiography is necessary to visualize micro-arteriovenous malformations in patients with cerebral hemorrhage and negative four-vessel angiography. Furthermore, the superselective endovascular approach has the advantage of offering immediate obliteration of the micro-shunt, thereby reducing or eliminating the risk of further hemorrhage.

Intraventricular cavernomas: three cases and review of the literature

OBJECTIVE AND IMPORTANCE

Cavernomas occur very rarely in the ventricular system. We report three cases of intraventricular cavernomas and review the literature.

CLINICAL PRESENTATION

A 16-year-old female patient presented with a sudden distal deficit of the left superior limb. She had a voluminous tumor involving the two lateral ventricles, with radiological evidence of recent hemorrhage. A 30-year-old man presented with generalized seizures and a right hemiplegia related to a 4-cm-diameter cavernoma in the two lateral ventricles involving the interhemispheric scissure through the corpus callosum and left centrum ovale. The radiological appearance was not typical and did not allow the diagnosis. A 42-year-old man had a cavernoma in the third ventricle, which was responsible for his short-term memory loss. This cavernoma had been revealed by computed tomography that was performed after intracerebral hemorrhage related to another cavernoma in the right parietal lobe occurred.

INTERVENTION

Stereotactic biopsies allowed the diagnosis of intraventricular cavernoma in the first case. Surgical removal via a right transcortical transventricular approach and a transcallosal approach in the first and second cases, respectively, was complete, resulting in good outcomes. Surgical removal via a right transcortical transventricular approach in the third case was partial.

CONCLUSION

Intraventricular cavernomas are so uncommon that only 42 well-documented cases have been previously reported in the literature. It seems that their radiological diagnosis may be difficult because of their uncommon location in the ventricular system and their voluminous size. A wrong preoperative diagnosis has sometimes been the cause of inefficient therapy, such as radiotherapy, for these surgically curable benign lesions.

Successful removal of cryptic arteriovenous malformation located at the upper ventral pons via subtemporal transtentorial approach

BACKGROUND

Lesions located at the ventral portion of the brain stem are still difficult to access surgically. We report herein a case of ventral pontine cryptic arteriovenous malformation that was successfully removed via a subtemporal-transtentorial approach.

CASE REPORT

An 18-year-old female patient experienced repetitive hemorrhagic attacks leading to a massive pontine hemorrhage with several neurologic deficits. Since angiography and magnetic resonance imaging failed to delineate the hemorrhagic origin, a combination of multiple approaches was initially attempted. The subtemporal-transtentorial approach made it possible to obtain an adequate operative view in this case. An angioma observed at the septum of the multilocular hematoma was totally removed. Pathologic examination of the resected specimen revealed it to be an arteriovenous malformation. Postoperatively, the patient showed unexpectedly good recovery despite the original massive pontine hemorrhage.

CONCLUSIONS

Several surgical approaches to the ventral pons have been proposed in the literature. While the subtemporal-transtentorial approach was useful in our patient, multiple routes should be considered to access a massive lesion of unknown extent at the ventral pons. The unexpected recovery observed in our patient suggests that surgery is an option in the treatment of this type of lesion.

Spontaneous thrombosis of an arteriovenous malformation

A patient with a spontaneously thrombosed arteriovenous malformation (AVM) presented with epilepsy. The CT and MRI appearances were of an intrinsic cerebral neoplasm with extensive surrounding vasogenic cerebral oedema and a mass effect. Histopathology confirmed a large thrombosed AVM. The natural history of AVMs and spontaneous thrombosis are reviewed.

Cavernous malformations of the brain stem. A review of 139 cases

A retrospective analysis of 139 patients with brain stem cavernous malformations is presented. The material consists of 41 cases from Bern and Phoenix and 98 further well-documented cases from the literature. Sixty-eight patients were male, 70 were female. The average age was 31.8 + 11.8 years. Sixty-two percent of the cavernous malformations were in the pons, 14% were in the mesencephalon, 12% were in the pontomesencephalic and in the pontomedullary junction, and 5% were in the medulla. Eighty-eight percent of the patients showed evidence of recent or previous hemorrhage, 55% had one hemorrhage. 17% had two hemorrhages, and 17% had three or more hemorrhages. Twelve patients died from a hemorrhage, 5 with the first bleeding and 7 with a rebleeding. The minimum bleeding rate was 2.7% per year and the average rebleeding rate 21% per year and per lesion. Most lesions had a diameter between 10 and 30 mm. Increase in size was observed in 12 of the patients; this corresponds to about 21% when only patients with a follow-up of at least one year are considered. In 93 patients the cavernous malformation was removed operatively while in 30 patients the lesion was not removed. In the group with conservative management at the end of the observation period (up to 25 and 32 years), 66.6% had no or only a slight neurological deficit, 6.7% were moderately disabled, 6.7% were completely dependent, and 20% had died. In the group treated surgically 83.9% had no or only a slight neurological deficit, and 15% were moderately disabled. One patient remained severely disabled, no patient died. The limitations of the retrospective nature of this study are stressed.

Controversies in the management of brainstem cavernous angioma: report of two cases

Two cases of cavernous angioma involving the medulla oblongata are presented. Both cases underwent surgical excision with excellent outcome. The use of surgery via craniectomy is contrasted with stereotactic radiosurgery in light of the known natural history of the lesions. As a result, it is suggested that surgical excision provides immediate protection from the risks of recurrent haemorrhage, establishes a tissue diagnosis, allows complete removal at the primary intervention, avoids complications of radiation-induced damage and is performed more easily in these vascular anomalies due to the presence of a capsule with surrounding gliotic tissue. Additionally, it is implied that the natural history of lesions in this region is still unclear. For these reasons, it is suggested that surgical excision should be the primary therapeutic intervention for cavernous angiomata that involve the brainstem.

Ruptured occult arteriovenous malformation associated with an unruptured intracranial aneurysm: report of three cases

Three patients who were admitted for intracranial hemorrhage are reported. Cerebral angiography demonstrated an aneurysm arising from the middle cerebral artery bifurcation. No other malformation was visible either on the computed tomographic scan or on angiography. The diagnosis was ruptured middle cerebral artery aneurysm with intracerebral hematoma. At surgery, there was no blood in the sylvian fissure and the aneurysm was not ruptured. Evacuation of the hematoma and thorough exploration of the cavity led to the discovery and resection of a small vascular anomaly typical of an arteriovenous malformation responsible for the hemorrhage. Occult vascular malformations and the association of aneurysm with arteriovenous malformations are discussed. In these 3 patients, the coexistence of these two malformations could be related to a common congenital abnormality.

Spontaneous disappearance of a huge cerebral arteriovenous malformation: case report

A case of spontaneous disappearance of a cerebral arteriovenous malformation (AVM) is reported. A 59-year-old woman, who had been diagnosed as having a huge AVM in the left occipital lobe 6 years before and who was monitored without treatment, complained of a sudden headache and vomiting. Computed tomography revealed an acute subdural hematoma, intracerebral hematoma, and subarachnoid hemorrhage, for which a craniotomy was performed. Cerebral angiograms performed 9 days after the operation demonstrated a decrease in the size of the AVM. Repeated cerebral angiograms performed a month later demonstrated complete disappearance of the AVM. Follow-up angiograms performed 19 months after hemorrhage confirmed complete disappearance of the AVM. Spontaneous disappearance is known to occur occasionally in small AVMs but rarely in huge ones such as the one presented here. Several possible mechanisms for spontaneous disappearance of AVMs are discussed.

Intracranial cavernous angioma

We report 14 cases of intracranial cavernous angioma, analyzing the clinical features, with special reference to the risk of bleeding, radiological images and treatment in these and in 153 published cases, 167 in all. Cerebral hemorrhage occurred in 44%: typical (intraparenchymal or subarachnoid) in 24.6%, and masked by epilepsy, headache or neurological deficits in 19.2%. In patients with the typical hemorrhagic pattern posthemorrhagic mortality was 12.2%. Of the patients who had a hemorrhage 42.5% were left with more or less disabling neurological deficits, and 16.4% had a rebleed. In discussing treatment we consider four groups of intracranial cavernous angioma: A) symptomatic in a zone of low surgical risk; B) asymptomatic with low surgical risk; C) symptomatic with high surgical risk; D) asymptomatic with high surgical risk. The treatment is surgical, except in the high risk asymptomatic variety, best followed initially with sequential CT scan and MRI and then considered for surgery if the lesion becomes symptomatic, increases in size or presents neuroradiological signs of bleeding.

An analysis of the natural history of cavernous angiomas

The advent of magnetic resonance (MR) imaging has permitted the recognition of many angiographically occult vascular malformations before the development of complications and subsequent surgical removal. This study reviews all patients at one institution who had radiographically identifiable vascular malformations believed to represent cavernous angiomas in order to obtain information on the natural history of this particular lesion. All 8131 craniospinal MR images performed at our medical center from January 1, 1986, to November 30, 1989, were reviewed, and 32 patients were identified with 76 lesions meeting the MR imaging criteria for cavernous angioma. Medical histories, physical examination records, and other data from these patients were then reviewed to determine the frequency of complications. Their mean age at latest follow-up examination (or at surgical removal of the lesion) was 37.6 years (range 16 to 72 years). Sixteen patients (50%) had a history of seizures, seven (22%) had focal neurological deficits, and three (9%) had clinically significant hemorrhage attributable to the cavernous angioma; six patients (19%) were asymptomatic. The estimated risk of hemorrhage for this population is 0.25%/person-year of exposure; the estimated risk of seizure development is 1.51%/person-year. Eight patients underwent surgical procedures, resulting in improved seizure control and/or lessened neurological deficit. Although these lesions are often excised with relative ease and minimal morbidity, the potential risks and benefits of surgery must be weighed carefully before removal of these relatively benign malformations.

Microsurgery of deep-seated cavernous angiomas: report of 26 cases

The authors review 26 patients with deep-seated cavernous angiomas which were removed by microsurgery. Ten of the angiomas were located in the insula and basal ganglia, 2 in the thalamus, 5 in the midbrain, 8 in the pons, and 1 in the brachium pontis. The patients were among 73 consecutive cases operated on between August 1983 and December 1989 for symptomatic cavernous angiomas in various locations. In 11 cases total excision of the cavernoma was achieved without producing additional neurological deficits. Postoperative neurological recovery was delayed in 7 patients. In the remaining 8, the complicated postoperative course was caused by bleeding from residual parts of the malformation or damage to long-tract pathways in two cases, respectively, vascular injury during dissection in three cases, and paradoxical air embolism in one case. In order to achieve a satisfactory surgical result, it is stressed that particular attention has to be paid to the operative approach, to careful dissection and complete removal of the malformation, to perforating arteries, and to anomalous venous drainage.

Intraventricular cavernous angioma. A survey

Since the availability of CT diagnosis 23 cases of intraventricular cavernous angioma (IVCA) have been published in the literature. Three additional cases have been operated upon in our Department. Based on these 26 cases the clinical data, radiological findings, treatment and outcome of IVCAs are reviewed.

Cerebral vascular malformations: applications of magnetic resonance imaging to differential diagnosis

Twelve patients with cerebral vascular malformations (5 cavernous angiomas, 1 thrombosed arteriovenous malformation, and 6 venous angiomas) were studied with magnetic resonance (MR) imaging. All lesions were clearly depicted. Characteristic MR findings were obtained mainly on T2-weighted images: a markedly low intensity area was always seen. The margins of arteriovenous malformation (AVM) and venous angioma were irregular while those of cavernous angioma were smooth in all planes on T2-weighted images. Gradient-echo (GrE) pulse sequences were more sensitive than T2-weighted spin echo (SE) in lesion detection. MR imaging could play an important role in the differential diagnosis of cerebral vascular malformations.

Parapontine trigeminal cryptic angiomas presenting as trigeminal neuralgia

Posterior fossa microvascular decompression surgery was attempted in 1257 patients with trigeminal neuralgia (TN), of whom seven had a very unusual cryptic angioma. The lesions were not visualized on preoperative enhanced computerized tomography scans, and serial angiography demonstrated a small vascular stain in only one case. The character of the facial pain was indistinguishable from TN caused by vascular compression and there was no other specific symptomatology. The patients' age and sex distributions were also compatible with classical TN. Cryptic angiomas presenting as typical TN without other symptoms have not been reported before, but they should be kept in mind in the differential diagnosis and surgical management of TN.

Cerebral cavernous angioma in children

Cerebral cavernous angioma is a rare vascular malformation at any age and is very rare in childhood. In the literature available to us, we have been able to trace only 50 cases, to which we have added the 6 cases from our own series. The incidence in pediatric group is higher at 0-2 years (26.8%) and at 13-16 years (35.7%). The clinical onset shows epilepsy in 45.4% of cases, hemorrhagic syndrome in 27.3%, intracranial hypertension in 16.4%, and focal neurological deficits in 10.9%. Furthermore, we discuss the neuroradiological features (CT, angiography, and MRI) and the therapy of pediatric cavernous angioma.

[Primary hematoma of the brain stem: considerations apropos of a case]

The case of a 48 year-old woman presenting with a primary pontine hematoma is reported. The clinical evolution simulated a brain stem tumor and the diagnosis of hematoma was not established before the operation. The preoperative neurological deficit improved except for a facial nerve palsy. These hematomas are thought to be due to rupture of "cryptic" arteriovenous malformations and should be differentiated from those secondary to systemic hypertension. The diagnosis of brain stem hematomas should be considered in any case of brain stem lesion, especially in young and normotensive patients.

What is a "cryptic" arteriovenous malformation?

Images

"Nidus sparing sign" on computerized tomography in intracerebral haemorrhage due to a rupture of arteriovenous malformation

The authors investigated the validity of noncontrast computerized tomography (NCCT) to predict the presence of arteriovenous malformations (AVM) as a cause of intracerebral haemorrhage (ICH) in the acute stage. They found a small iso- or slightly hyperdense nodular or tubular defect devoid of haematoma in its periphery on NCCT in 8 of the 13 AVM cases that underwent both NCCT and contrast CT. This CT finding was named "nidus sparing sign" (NSS). This haematoma-free notch was enhanced on contrast infusion and confirmed to correspond to the AVM nidus surgically and pathologically. In one case with negative angiograms, a small AVM was verified histologically within the tissue corresponding to the NSS. The NSS noted on the NCCT could be of great value in case emergency surgery is needed for comatose patients with ICH, particularly lobar ICH, without enough time left to undergo angiography and/or magnetic resonance imaging. Neurosurgeons are able to safely perform an evacuation of the haematoma keeping in mind the possibility of a ruptured AVM and if so, the spatial relationship between the AVM nidus and the haematoma. This might also be a valuable CT sign in deciding whether or not angiography should be undertaken in ICH cases.

Angiographically occult arteriovenous malformations

Eight cases of histopathologically proven arteriovenous malformations (AVM's) which were not visualized on angiography are presented. As is typical with these lesions, most of the patients in this series presented with hemorrhage, seizures, or episodic or progressive neurological symptoms suggestive of a neoplasm. The diagnosis of angiographically occult AVM was highly suspected preoperatively in each case based on the combination of computerized tomography (CT) and magnetic resonance (MR) findings. The CT scans in all cases showed moderately hyperdense lesions which enhanced mildly or moderately in a nonhomogeneous pattern with administration of contrast material. The MR image showed one or more bright areas interspersed with areas of low or absent signal peripherally or centrally on both T1- and T2-weighted images. The AVM was totally excised in seven patients and partially excised in one patient, with favorable results in all. The clinical management and differential diagnosis of angiographically occult AVM's are discussed. In patients with a clinical course and radiological studies suggestive of an occult AVM, removal of the lesion, if accessible, should be performed in order to rule out a neoplasm and prevent subsequent hemorrhage and progression of symptoms.

Clinical, radiological, and pathological spectrum of angiographically occult intracranial vascular malformations. Analysis of 21 cases and review of the literature

The clinical, radiological, and histopathological features of 21 cases of angiographically occult intracranial vascular malformations (AOIVM's) are analyzed, and a review of 241 additional appropriately documented, histologically verified cases collected from the literature is presented. In all, there were 115 (43.8%) arteriovenous malformations, 82 (31.2%) cavernous angiomas, 26 (9.9%) venous angiomas, 10 (3.8%) cases of capillary telangiectasis, and 29 (11%) mixed or unclassified angiomas. The result of the analysis shows that there are no essential differences in the patterns of clinical presentation, the computerized tomography (CT) appearance, or the surgical prognosis among these pathological types of vascular malformations. Certain histological features common to all AOIVM's (such as the small caliber, the more or less complete thrombosis of the malformed vessels, and the changes induced in the surrounding brain tissue by repeated microhemorrhages) seem to determine the biological behavior of the anomaly rather than the predominant type of vessel involved. Thus, subdivision of AOIVM's into the four classical pathological types has little practical value. Most AOIVM's are visualized by the CT scan and show a rather typical appearance. Surgical removal, which prevents rebleeding and ameliorates or suppresses seizure activity, is usually easy to perform and represents the treatment of choice for patients with clinically symptomatic AOIVM's.

The association of venous and cavernous malformations. Report of four cases and discussion of the pathophysiological, diagnostic, and therapeutic implications

Four cases of venous malformation associated with a cavernous malformation are reported. Because cavernous malformations are often angiographically occult and do not have a characteristic appearance on computed tomography (CT), they are seldom recognized preoperatively and may be missed if the surgical specimen is not carefully reviewed. This association, however, may not be rare and may explain the presence of symptomatic venous malformations. Magnetic resonance (MR) imaging is particularly sensitive in detecting cavernous malformations and is highly specific. It is recommended that every symptomatic venous malformation be worked-up with a high field strength MR Unit.

The MRI appearance of cavernous malformations (angiomas)

The angiographic, computerized tomography (CT), and magnetic resonance imaging (MRI) findings were compared in 10 patients with a total of 16 pathologically verified cavernous angiomas. Only three lesions had abnormal vasculature in the form of venous pooling or a capillary blush. The CT scans were positive in seven patients and detected 14 lesions, while high-field strength (1.5 Tesla) MRI was positive in each case and demonstrated 27 distinct lesions. On T2-weighted MRI, the combination of a reticulated core of mixed signal intensity (SI) with a surrounding rim of decreased SI strongly suggests the diagnosis of a cavernous malformation. Smaller lesions appear as areas of decreased SI (black dots). The sensitivity of MRI is based on magnetic susceptibility and possibly diffusion effects related to field heterogeneity that is more conspicuous on high-field imaging and caused by the presence of excessive iron (hemosiderin).

Angiographically occult arteriovenous malformations of the brainstem

Two cases of infratentorial arteriovenous malformations that were occult to angiography but detected by computed tomography are discussed. In both cases a preoperative diagnosis of low-grade glioma was considered. Attention is drawn to the relative paucity of such lesions below the tentorium.

Cavernomas of the central nervous system: clinical syndromes, CT scan diagnosis, and prognosis after surgical treatment in 25 cases

We present our clinical experience and the results of surgical management with 25 cavernomas of the CNS, treated in our hospital in the last 10 years. The location of the lesion assessed by clinical and CT scan examinations, proved to be the most significative factor determining the prognosis of cavernomas of the CNS, after surgical removal. The symptoms started in most of the cases in the third decade of life. 19 cases were located in the cerebral hemispheres and produced three well defined clinical syndromes: Irritative syndrome (seizures) present in 70% of the cases. Space-occupying lesion syndrome (20%) and haemorrhagic syndrome (10%). The remaining six cases were located within the basal ganglia, brainstem, pineal region, cerebellum and spinal cord, showing a progressive course. CT scan studies were performed on 24 cases. The characteristic image of a cavernoma is represented by a moderately hyperdense nodule with discreet contrast uptake. Calcification was observed in and around the lesions in 33% of the cases. Perilesional hypodensities suggestive of brain tissue atrophy were noted in 22% of the CT scans. On the other hand, 12% of cerebral hemisphere cavernomas showed atypical CT scan images that suggested an erroneous diagnosis of cystic gliomas. Radical surgical removal was performed in all cases. The postoperative results varied according to the location of the lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

The predicted value of arteriography in nontraumatic intracerebral hemorrhage

We retrospectively assessed the diagnostic value of cerebral arteriography for the search of an etiology in 102 patients with nontraumatic intracerebral hemorrhages evaluated between 1980 and 1985. Arteriography was diagnostic in 22 of 50 non-hypertensive patients and in only 6 of 47 hypertensive patients. Five patients with a bleeding diathesis had normal arteriography. From the total group, we found 12 saccular aneurysms, 9 arteriovenous malformations, 3 cases of moya-moya and 3 instances of superior sagittal sinus thrombosis. One patient had metastatic choriocarcinoma. Sites of hemorrhage among all patients with diagnostic arteriograms were: lobar 19, intraventricular 5, thalamic 2, caudate 1, and corpus callosum 1. Lobar hemorrhages in the non-hypertensive group and intraventricular hemorrhages in hypertensive individuals had the highest yield of arteriographic abnormalities. We believe cerebral arteriography is indicated in non-hypertensive patients with lobar hemorrhages. Most hypertensive patients, in particular those with putaminal hemorrhages, do not require arteriography.

Positron emission tomography of cavernous haemangiomas of the brain

Four cases with lesions suspected to be low-grade intracerebral tumours but later proved to be cavernous haemangiomas are described. The patients were examined with contrast enhanced CT and with positron emission tomography (PET). The lesions were partly calcified with a mild or no mass effect and a slight contrast enhancement at CT. There were signs of disrupture of the blood-lesion barrier also on radionuclide studies. PET with 11C-methionine and 11C-glucose showed a normal or decreased accumulation of the tracers. This combination of findings has not been encountered in intracranial tumours. As a comparison, one case of glioblastoma is described. In this patient, the CT findings suggested a cavernous haemangioma. However, PET showed a markedly increased accumulation of 11C-methionine, which is compatible with brain tumour but not with haemangioma.

Radical surgery on cavernous angioma of the brainstem

Four cases of cavernous angioma of the brainstem are reported. Three patients had angiomas of the pons; one had a lesion extending from the third ventricle to the hypothalamus. In the three patients directly operated upon the entire lesion was excised. The lesions were delimited by reactive scar tissue, so that by means of a careful technique severe associated disorders were avoided postoperatively. The importance of computed tomography for postoperative observation and the effectiveness of nuclear magnetic resonance-computed tomography have been demonstrated. It is thought that henceforth surgical treatment of brainstem lesions will be found appropriate in a far greater number of cases.

Intracranial and orbital cavernous angiomas. A review of 30 cases

The authors review 30 documented cases of intracranial and orbital cavernous angiomas treated at their institution between 1965 and 1984. The diagnosis was based on computerized tomography (CT) or surgery; three patients were treated in the pre-CT era (1965 to 1976) and 27 since the advent of CT. The number of cases diagnosed preoperatively markedly increased after the introduction of CT, and 22 cases were verified histopathologically at surgery. Six cases were in children (aged 2 months to 17 years) and 24 in adults (aged 19 to 73 years). There was no significant sex difference (male:female ratio was 14:16). Nineteen lesions were intraparenchymal, five were intraventricular, three were in the middle fossa, two were intraorbital, and one originated from the tentorium. Symptoms varied according to the site of the lesion; hemorrhage occurred in 11 cases. Calcifications were seen on CT scans in all cases, but on plain skull films in only two. Angiography revealed hypovascular masses in all cases excluding those with lesions in the middle fossa; in two cases, tumor stain could be detected only with prolonged-injection angiography. Radionuclide brain scanning showed a dense hot area in eight of 19 patients. Recent experience has shown that magnetic resonance imaging clarified anatomic relationships that were obscure on CT. The overall outcome was favorable except for one patient who died in the postoperative period. The clinical results in this series are summarized and some diagnostic and therapeutic problems are discussed.

Lobar intracerebral hemorrhage: etiology and a long-term follow-up study of 32 patients

Thirty-two patients with lobar hematoma were encountered during a period of six and a half years. Of these patients, 13 had arterial hypertension, 7 had other etiologies, and the remaining 12 were without apparent etiology. In 5 of these patients, cryptic angiomas were suspected from angiograms and CT scans. In one young patient, there was a later recurrence of hemorrhage that resulted in death. Our experience in this series and a review of the literature have led us to conclude that, in young normotensive patients with lobar hematoma, surgical intervention may be a reasonable consideration so that evacuation of the hematoma may be accomplished and a detailed search for small angiomatous malformations may be carried out with a view to preventing recurrences.

Spontaneous disappearance of intracranial arterio-venous malformations

4 cases of spontaneous disappearance of intracranial arteriovenous malformations are reported. All the malformations were in the rolandic-parietal area, and fed in most cases by the MCA. In one case, the malformation was associated with a proximal aneurysm. One malformation was large, one medium-sized, and two small. Venous drainage was towards the longitudinal sinus in all cases. Presenting symptoms consisted of epilepsy in 2 cases, and intracerebral haemorrhage in 2 cases. Disappearance of the AVM was documented by angiography from 1 to 15 years after diagnosis, and was preceded by a new haemorrhage in 2 cases. Acute or gradual thrombosis of the AVM is suggested as the most likely cause of the disappearance of an AVM. Spontaneous thrombosis of an AVM should be considered as an aspect of the pathological entity known as "thrombosed AVM". Guidelines for the management of patients exhibiting spontaneous disappearance of an AVM are briefly discussed.

Hemangioblastoma presenting with intraparenchymatous hemorrhage

✓ The authors report six cases of hemangioblastoma presenting with apoplectic symptoms but with no history related to the tumor. In each case, computerized tomography disclosed an intraparenchymatous hemorrhage, which was located supratentorially in four and in the cerebellum in the remaining two. Angiography revealed an abnormal vascular blush in two cases, but no abnormal vessels or tumor blush in the other four. In all cases, a solid tumor with abnormal vessels, such as red veins and feeding arteries, was found within or adjacent to the hemorrhage at surgery. The possibility of hemangioblastoma should be kept in mind as a cause of intraparenchymatous hemorrhage, particularly subcortical. Evacuation of the hematoma should be carefully carried out, and the whole hematoma wall should be thoroughly investigated for abnormal vessels or a solid mass.

Giant cystic cavernoma in a child. Case report

A totally cystic giant cavernous hemangioma is described in a 3-year-old girl. The clinical presentation and computerized tomography findings were both unique. The patient was successfully treated by surgery.

Angiographically occult cerebral vascular malformations with abnormal computed tomography

Two cases of histologically proven cerebrovascular malformation were detected by computed tomography (CT) scanning but not by cerebral angiography. One of the patients had a cavernous angioma and the other an arteriovenous malformation. Caution is advised in assuming that angiographically avascular lesions demonstrable by CT scanning are not vascular malformations.

Thrombosed arteriovenous malformations of the brain. An important entity in the differential diagnosis of intractable focal seizure disorders

Thrombosed arteriovenous malformations (AVM's) in patients with no previous history of hemorrhage are uncommon but benign lesions that present with clinical and radiographic findings which are often indistinguishable from those of other mass lesions, particularly low-grade gliomas. The authors report seven cases of thrombosed AVM's presenting as intractable seizure disorders in which the radiographic studies had suggested a low-grade glioma. All seven patients are now seizure-free 2 to 40 months postoperatively. The importance of surgical exploration in the management of such patients is emphasized. A review of 32 cases reported in the literature is presented. The reasons why angiography may fail to demonstrate an AVM, and the possible etiologies for the spontaneous thrombosis of an AVM are discussed.

Cryptic arteriovenous malformation of the choroid plexus of the third ventricle

A patient with a history of subarachnoid hemorrhage is reported. CT scan evidenced a high-density, round lesion in the anterior part of the third ventricle. A full angiographic study demonstrated no vascular malformation. After removal of a circumscribed hematoma in the anterior part of the third ventricle, an arteriovenous malformation of the choroid plexus was excised.

Microsurgical removal of paraventricular cavernous angiomas. Report of two cases

Two cases of paraventricular cavernous angiomas are presented. In one, the cavernous angioma was found in the right wall of the fourth ventricle, and in the other in the right thalamus encroaching upon the third ventricle. Both patients had onset of symptoms suggesting a tumor. Good results were obtained by the microsurgical approach to these malformations. The computerized tomography findings typical of cavernous angiomas are reviewed

Intrachiasmatic arteriovenous malformation. Case report

A patient presented with an abrupt monocular decrease in visual acuity and a bitemporal hemianopsia. At surgery, a totally intrachiasmatic arteriovenous malformation was removed, with subsequent resolution of the visual deficit.

Benign intracranial hypertension vs. intracranial arteriovenous malformation: a possible CT dilemma

A nine-year-old boy, presenting only with signs of increased ICP, underwent computerized tomography. This examination demonstrated no abnormalities in the precontrast scan. Following C. E., it showed scattered areas of blood-like density in both hemispheres, as well as a presumedly abnormal vessel in the left occipital region and dilated vein of Galen, sinus rectus, and tentorial veins. The presumptive diagnosis of left occipital AVM was not confirmed by angiography, which also ruled out obstructions of the intracranial sinuses. The possible mechanism responsible for this atypical CT picture is briefly discussed in the light of pertinent literature. It is suggested that careful consideration should be given to the indications for angiography in similar cases, in the presence of a "hypervascular" aspect of the postcontrast CT scan, particularly if a considerable amount of contrast medium has been used.

The computerized tomographic appearance of angiographically occult arteriovenous malformations of the brain

Eight patients with a histologically proven angiographically occult arteriovenous malformation of the brain had plain and infused computed tomographic (CT) examinations. In five cases angiography revealed a hypovascular mass in three cases the angiogram was normal. On CT examination a high density lesion (six cases) and ventricular asymmetry (five cases) were demonstrated. In three patients presenting with intracerebral hemorrhage, the high density appearance and ventricular compression were accounted for by the presence of hematoma. In three of five seizure patients the high density lesion was associated with calcification while ipsilateral (one case) and contralateral (one case) enlargement of the lateral ventricle was seen. In five of the eight cases the vascular nature of the lesion was suggested by vascular enhancement of the infused CT scan. Glioma was a common misdiagnosis.

Cerebral cavernous angiomas in children

Five cases of cerebral cavernous angiomas in children are presented. Three children had seizures as the sole manifestation of the lesion, and two had intracerebral bleeding. These malformations are encountered more commonly in adults in the third to fifth decade, and are found most frequently in the white matter of the cerebral hemispheres. Intracranial bleeding, seizures, headaches, and slowly developing focal signs are the usual presenting complaints. In childhood, seizures are the initial symptom of the malformation in many cases. The value of computerized tomography (CT) in the detection of such malformations is stressed, and CT findings that are characteristic of cavernous angiomas are described.