Pituitary adenomas with invasion of the cavernous sinus space: a magnetic resonance imaging classification compared with surgical findings

We present 25 pituitary adenomas that were confirmed surgically to have invaded the cavernous sinus space. The surgical results are compared with the preoperative magnetic resonance imaging findings. For comparable radiological criteria, we classified parasellar growth into five grades. This proposed classification is based on coronal sections of unenhanced and gadolinium diethylene-triamine-pentaacetic acid enhanced magnetic resonance imaging scans, with the readily detectable internal carotid artery serving as the radiological landmark. The anatomical, radiological, and surgical conditions of each grade are considered. Grades 0, 1, 2, and 3 are distinguished from each other by a medial tangent, the intercarotid line--through the cross-sectional centers--and a lateral tangent on the intra- and supracavernous internal carotid arteries. Grade 0 represents the normal condition, and Grade 4 corresponds to the total encasement of the intracavernous carotid artery. According to this classification, surgically proven invasion of the cavernous sinus space was present in all Grade 4 and Grade 3 cases and in all but one of the Grade 2 cases; no invasion was present in Grade 0 and Grade 1 cases. Therefore, the critical area where invasion of the cavernous sinus space becomes very likely and can be proven surgically is located between the intercarotid line and the lateral tangent, which is represented by our Grade 2. We also measured tumor growth rates, using the monoclonal antibody KI-67, which shows a statistically higher proliferation rate (P < 0.001) in adenomas with surgically observed invasion into the cavernous sinus space, as compared with noninvasive adenomas.

Idiopathic intracranial hypertension: the prevalence and morphology of sinovenous stenosis

OBJECTIVE

To determine the prevalence and nature of sinovenous obstruction in idiopathic intracranial hypertension (IIH) using auto-triggered elliptic-centric-ordered three-dimensional gadolinium-enhanced MR venography (ATECO MRV).

METHODS

In a prospective controlled study, 29 patients with established IIH as well as 59 control patients underwent ATECO MRV. In a randomized blinded fashion, three readers evaluated the images. Using a novel scoring system, each reader graded the degree of stenosis seen in the transverse and sigmoid sinuses of each patient.

RESULTS

There was excellent agreement across the three readers for application of the grading system. Substantial bilateral sinovenous stenoses were seen in 27 of 29 patients with IIH and in only 4 of 59 control patients.

CONCLUSION

Using ATECO MRV and a novel grading system for quantifying sinovenous stenoses, the authors can identify IIH patients with sensitivity and specificity of 93%.

Dose-response tolerance of the visual pathways and cranial nerves of the cavernous sinus to stereotactic radiosurgery

As the number of patients treated with stereotactic radiosurgery increases, it becomes particularly important to define with precision adverse effects on distinct structures of the nervous system.

OBJECT

This study was designed to assess the dose-response tolerance of the visual pathways and cranial nerves after exposure of the cavernous sinus to radiation.

METHODS

A total of 66 sites in the visual system and 210 cranial nerves of the middle cranial fossa were investigated in 50 patients who had undergone gamma knife treatment for benign skull base tumors. The mean follow-up period was 40 months (range 24-60 months). Follow-up examinations consisted of neurological, neuroradiological, and neuroophthalmological evaluations. The actuarial incidence of optic neuropathy was zero for patients who received a radiation dose of less than 10 Gy, 26.7% for patients receiving a dose in the range of 10 to less than 15 Gy, and 77.8% for those who received doses of 15 Gy or more (p < 0.0001). Previously impaired vision improved in 25.8% and was unchanged in 51.5% of patients. No sign of neuropathy was seen in patients whose cranial nerves of the cavernous sinus received radiation doses of between 5 and 30 Gy. Because tumor control appeared to have been achieved in 98% of the patients, the deterioration in visual function cannot be attributed to tumor progression.

CONCLUSIONS

The structures of the visual pathways (the optic nerve, chiasm, and tract) exhibit a much higher sensitivity to single-fraction radiation than other cranial nerves, and their particular dose-response characteristics can be defined. In contrast, the oculomotor and trigeminal nerves have a much higher dose tolerance.

Cerebral cavernous malformations: natural history and prognosis after clinical deterioration with or without hemorrhage

Despite recent studies of the natural history of cavernous malformations, there remains significant uncertainty concerning hemorrhage rates and the importance of lesion location. Controversy arises over varying definitions of "hemorrhage." What is ultimately important to the patient is the occurrence of a neurological event, which may or may not be associated with radiologically documented hemorrhage, as well as the chance of recovery after such an event. The purpose of this study was to determine the rates of occurrence and sequelae of neurological events in 173 patients referred to our vascular malformation clinic with cavernous malformations. All patient data were entered into a database. The mean age at presentation for the 173 patients was 37.5 years. The lesion location was deep (brainstem, cerebellar nuclei, thalamus, or basal ganglia) in 64 patients (37%) and superficial in 109 (63%). Thirty-one patients (18%) had multiple lesions. Disease presentation was due to seizures in 62 patients (36%), hemorrhage in 44 (25%), focal neurological deficit without documented hemorrhage in 35 (20%), headache alone in 11 (6%), and incidental findings in 21 patients (12%). The results obtained in the 110 patients eligible for follow-up review were used to derive information on the rates of hemorrhage and neurological events. An interval event (neurological deterioration) required both symptoms and signs. The total mean follow-up period was 46 months, the majority (65%) of which was prospective. There were 18 interval events in 427 patient-years of follow-up review, for an overall annual event rate of 4.2%. Location was the most important factor for predicting interval event occurrence, with significantly higher rates for deeply located (10.6%/year) compared with superficially located lesions (0%/year) (p = 0.0001). Of patients suffering a neurological event, only 37% had complete resolution of their deficits. This largely prospective study indicates that deep cavernous malformations carry a worse prognosis than superficial lesions with respect to annual rates of neurological deterioration. The alarming rate of adverse clinical events occurring in patients with deep lesions is punctuated by the fact that less than one-half of them recover fully during long-term follow-up review.

Stereotactic radiosurgery providing long-term tumor control of cavernous sinus meningiomas

OBJECT

To evaluate long-term outcomes of patients who have undergone stereotactic radiosurgery for cavernous sinus meningiomas, the authors retrospectively reviewed their 14-year experience with these cases.

METHODS

One hundred seventy-six patients harbored meningiomas centered within the cavernous sinus. Seventeen patients were lost to follow-up review, leaving 159 analyzable patients, in whom 164 procedures were performed. Seventy-six patients (48%) underwent adjuvant radiosurgery after one or more attempts at surgical resection. Eighty-three patients (52%) underwent primary radiosurgery. Two patients (1%) had previously received fractionated external-beam radiation therapy. Four patients (2%) harbored histologically verified atypical or malignant meningiomas. Conformal multiple isocenter gamma knife surgery was performed. The median dose applied to the tumor margin was 13 Gy. Neurological status improved in 46 patients (29%), remained stable in 99 (62%), and eventually worsened in 14 (9%). Adverse effects of radiation occurred after 11 procedures (6.7%). Tumor volumes decreased in 54 patients (34%), remained stable in 96 (60%), and increased in nine (6%). The actuarial tumor control rate for patients with typical meningiomas was 93.1 +/- 3.3% at both 5 and 10 years. For the 83 patients who underwent radiosurgery as their sole treatment, the actuarial tumor control rate at 5 years was 96.9 +/- 3%.

CONCLUSIONS

Stereotactic radiosurgery provided safe and effective management of cavernous sinus meningiomas. We believe it is the preferred management strategy for tumors of suitable volume (average tumor diameter < or = 3 cm or volume < or = 15 cm3).

Petroclival meningiomas: surgical experience in 109 cases

The surgical removal of petroclival meningiomas has historically been associated with a high incidence of morbidity and mortality. The 109 consecutive patients included in the present retrospective study represent a combined series of tumors operated on by the four authors during a period from 1980 to 1992. The series is composed of 40 men and 69 women ranging in age from 25 to 75 years (mean 51 years). Surgical approaches to tumors in this series included simple retromastoid (60 cases), combined supra- and infratentorial petrosal (22), transtemporal (primary transsigmoid retrolabyrinthine, translabyrinthine, or transcochlear (12), subtemporal (11), and frontotemporal transcavernous (eight). Gross-total removal was achieved in 75 patients (69%). Recurrence or progression of disease occurred in 14 patients (13%) over a 6.1-year mean follow-up period, and it was found within the cavernous sinus in 12 of these cases. Four recurrent cases demonstrated histological compatibility with malignant meningioma. Perioperative death occurred in four patients, and there were 56 significant complications in 35 other patients. Review of this series, with the attendant complications, has facilitated the authors' decision-making when considering the risk of gross-total removal in selected patients with asymptomatic cavernous sinus invasion or tumor adherent to the brainstem.

An analysis of the natural history of cavernous malformations

BACKGROUND

The treatment of cavernous malformations has been controversial. Some reports suggest that surgical resection of the lesion for the prevention of recurrent hemorrhage should not be considered because of low hemorrhagic risk. However, the role of surgery in management of cavernous malformations is undergoing reevaluation. The decision for surgical resection should be based on a careful analysis of the natural history of this lesion, which is not well understood.

METHODS

We investigated, retrospectively, the natural history of 108 cavernous malformations in 62 patients. Individual cavernous malformations were divided into four categories on the basis of magnetic resonance (MR) findings. The pattern of clinical and radiologic presentation and outcomes of management were analyzed.

RESULTS

The age of the patients ranged from 4-63 years (mean: 32.2 years). Multiple lesions were found in 13 of 62 patients (21%) and two of these patients were siblings. Twenty-five out of 62 patients had suffered recurrent symptoms. The bleeding rate was 2.3%/person/year (1.4%/lesion/year) during 2509.6 patient years. There were no significant differences between the bleeding rates of each type of lesion. During the follow-up period of 12-48 months (mean: 22.4 months), two of 28 patients conservatively treated had recurrent hemorrhages (rebleeding rate: 3.8%/person/year). During the follow-up period of 12-66 months (mean: 21.7 months), recurrent hemorrhages were observed in two of 17 patients with radiosurgery (rebleeding rate: 7.8%/person/year).

CONCLUSION

Our study has provided a profile of the natural history of these lesions. Based on our results, we recommend surgical excision of cavernous malformations in those patients with recurrent symptoms or acute progressive symptoms.

Endoscopic transsphenoidal approach: adaptability of the procedure to different sellar lesions

OBJECTIVE

To demonstrate the flexibility of the endoscopic transsphenoidal approach, with respect to nasal and paranasal anatomic features and the extension of different sellar lesions, for customization of the procedure for specific conditions.

METHODS

In 16 of 170 consecutive endoscopic transsphenoidal operations, some modifications of the standard approach were adopted to optimize surgical removal of different lesions. These modifications consisted of a hemisphenoidotomy, a partial ethmoidectomy, extended sellar floor opening toward the planum sphenoidale or the clivus, enlarged opening of the sphenoid ostium area with ipsilateral removal of the superior turbinate, and a bilateral approach.

RESULTS

The endoscopic endonasal procedure is easily adaptable to different specific conditions, with slight changes in the standard approach (more or less invasive). Therefore, this surgical procedure is satisfactory for different lesion locations and for the nasal and paranasal sinus anatomic features of individual patients.

CONCLUSION

The endoscopic surgical route should be tailored to different sellar lesions, and some modifications of the procedure are recommended in selected cases.

Formation of intracerebral cavernous malformations after radiation treatment for central nervous system neoplasia in children

OBJECT

Radiation is a common treatment modality for pediatric brain tumors. The authors present a retrospective review of six children who developed cerebral cavernous malformations after they underwent radiation treatment for central nervous system (CNS) neoplasia and propose two possible models to explain the formation of cavernous malformations.

METHODS

Three boys, aged 13, 9, and 17 years, suffered intracerebral hemorrhages from cerebral cavernous malformations 87, 94, and 120 months, respectively, after they received whole-brain radiation therapy (WBRT) for acute lymphocytic leukemia. A 10-year-old girl and a 19-year-old man developed temporal lobe cavernous malformations 46 and 48 months, respectively, after they received radiation therapy for posterior fossa astrocytomas. A 12-year-old girl developed a temporal lobe cavernous malformation 45 months after WBRT was administered for a medulloblastoma. In all of these cases the cavernous malformation appeared in the irradiated field, was not known to be present prior to radiation therapy, and developed after a latency period following treatment. The incidence of cavernous malformations in these patients suggests that children who undergo radiation therapy of the brain may have an increased risk of hemorrhage.

CONCLUSIONS

Two possible models may explain the formation of cavernous malformations following brain radiation in these patients. First, the cavernous malformations may form de novo in response to the radiation. Second, the cavernous malformations may have been present, but radiographically occult, at the time of radiation therapy and may have hemorrhaged in response to the radiation. The authors conclude that cavernous malformations may develop after brain radiation and propose a possible mechanism for this formation.

Cavernous sinus invasion by pituitary adenoma: MR imaging

PURPOSE

To define magnetic resonance (MR) imaging criteria for the diagnosis of cavernous sinus invasion by pituitary adenoma.

MATERIALS AND METHODS

The MR images obtained in 106 patients (86 female, 20 male; age range, 16-71 years) were reviewed retrospectively by two physicians. The standard-of-reference criteria for invasion were the surgical findings. A chi(2) analysis was performed, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for nine groups of MR imaging signs were computed.

RESULTS

Invasion of the cavernous sinus was certain (PPV, 100%) if the percentage of encasement of the internal carotid artery (ICA) by tumor was 67% or greater. It was highly probable if the carotid sulcus venous compartment was not depicted (PPV, 95%) or the line joining the lateral wall of the intracavernous and supracavernous ICAs was passed by the tumor (PPV, 85%). It was definitely not invaded (NPV, 100%) if the percentage of encasement of the intracavernous ICA was lower than 25% or the line joining the medial wall of the intracavernous and supracavernous ICAs was not passed by the tumor.

CONCLUSION

The radiologic diagnosis of cavernous sinus invasion by pituitary adenoma remains difficult, but the above-mentioned criteria may be of assistance.

Giant pituitary tumors: a study based on surgical treatment of 118 cases

BACKGROUND

The aim of the study is to analyze the nature, extensions, and dural relationships of hormonally inactive giant pituitary tumors. The relevance of the anatomic relationships to surgery is analyzed.

METHODS

There were 118 cases of hormonally inactive pituitary tumors analyzed with the maximum dimension of more than 4 cm. These cases were surgically treated in our neurosurgical department from 1995 to 2002. Depending on the anatomic extensions and the nature of their meningeal coverings, these tumors were divided into 4 grades. The grades reflected an increasing order of invasiveness of adjacent dural and arachnoidal compartments. The strategy and outcome of surgery and radiotherapy was analyzed for these 4 groups. Average duration of follow-up was 31 months.

RESULTS

There were 54 giant pituitary tumors, which remained within the confines of sellar dura and under the diaphragma sellae and did not enter into the compartment of cavernous sinus (Grade I). Transgression of the medial wall and invasion into the compartment of the cavernous sinus (Grade II) was seen in 38 cases. Elevation of the dura of the superior wall of the cavernous sinus and extension of this elevation into various compartments of brain (Grade III) was observed in 24 cases. Supradiaphragmatic-subarachnoid extension (Grade IV) was seen in 2 patients. The majority of patients were treated by transsphenoidal route.

CONCLUSIONS

Giant pituitary tumors usually have a meningeal cover and extend into well-defined anatomic pathways. Radical surgery by a transsphenoidal route is indicated and possible in Grade I-III pituitary tumors. Such a strategy offers a reasonable opportunity for recovery in vision and a satisfactory postoperative and long-term outcome. Biopsy of the tumor followed by radiotherapy could be suitable for Grade IV pituitary tumors.

Analysis of treatment outcome after stereotactic radiosurgery for cavernous sinus meningiomas

OBJECT

The long-term outcome of stereotactic radiosurgery for cavernous sinus (CS) meningiomas is not fully understood. The authors retrospectively reviewed their experience with 40 CS meningiomas treated with gamma knife radiosurgery.

METHODS

Follow-up periods for the 40 patients ranged from 12 to 123 months (median 42 months), and the overall tumor control rates were 86.4% at 3 years and 82.3% at 10 years. Factors associated with tumor recurrence in univariate analysis were histological malignancy (p < 0.0001), partial treatment (p < 0.0001), suprasellar tumor extension (p = 0.0201), or extension in more than three directions outside the CS (p = 0.0345). When the tumor was completely covered with a dose to the margin that was higher than 14 Gy (Group A, 22 patients), no patient showed recurrence within the median follow-up period of 37 months. On the other hand, when a part of the tumor was treated with 10 to 12 Gy (Group B, 15 patients) or did not receive radiation therapy (Group C, three patients), the recurrence rates were 20% and 100%, respectively. Neurological deterioration was seen in nine patients, but all symptoms were transient or very mild.

CONCLUSIONS

The data indicate that stereotactic radiosurgery can control tumor growth if the whole mass can be irradiated by dosages of more than 14 Gy. When optimal radiosurgical planning is not feasible because of a tumor's large size, irregular shape, or proximity to visual pathways, use of limited surgical resection before radiosurgery is the best option and should provide sufficient long-term tumor control with minimal complications.

Seizure Outcome after Resection of Cavernous Malformations Is Better When Surrounding Hemosiderin-stained Brain Also Is Removed

PURPOSE

Considering the epileptogenic effect of cavernoma-surrounding hemosiderin, assumptions are made that resection only of the cavernoma itself may not be sufficient as treatment of symptomatic epilepsy in patients with cavernous malformations. The purpose of this study was to test the hypothesis whether seizure outcome after removal of cavernous malformations may be related to the extent of resection of surrounding hemosiderin-stained brain tissue.

METHODS

In this retrospective study, 31 consecutive patients with pharmacotherapy-refractory epilepsy due to a cavernous malformation were included. In all patients, cavernomas were resected, and all patients underwent pre- and postoperative magnetic resonance imaging (MRI). We grouped patients according to MRI findings (hemosiderin completely removed versus not/partially removed) and compared seizure outcome (as assessed by the Engel Outcome Classification score) between the two groups.

RESULTS

Three years after resection of cavernomas, patients in whom hemosiderin-stained brain tissue had been removed completely had a better chance for a favorable long-term seizure outcome compared with those with detectable postoperative hemosiderin (p=0.037).

CONCLUSIONS

Our study suggests that complete removal of cavernoma-surrounding hemosiderin-stained brain tissue may improve epileptic outcome after resection of cavernous malformations.

Unilateral Duane's retraction syndrome (Type 1)

Duane's retraction syndrome (DRS) is a congenital eye movement disorder characterized by adduction deficiency, abduction limitation, globe retraction, and palpebral fissure narrowing on attempted adduction. In a case of unilateral DRS, the right side of the brainstem, cavernous sinus, and orbit were completely normal. The left abducens nucleus contained no cell bodies from motor neurons, but in its rostral portion, it contained several small cell bodies believed to be compatible with internuclear neurons. The left abducens nerve was absent. The left lateral rectus muscle was partially innervated by branches from the inferior oculomotor nerve.

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.

Infiltration of the carotid artery by cavernous sinus meningioma

Intracranial meningiomas are known to infiltrate surrounding structures such as the calvaria and dural sinuses, and the brain itself. The issue of whether meningiomas invade major intracranial arteries is of clinical importance, particularly in the case of meningiomas of the cavernous sinus. If a meningioma has not invaded the carotid artery wall, complete tumor removal may be accomplished with careful dissection from the carotid artery; however, if the tumor has infiltrated the wall of the carotid artery, complete removal may require sacrifice of the artery. To determine whether cavernous sinus meningiomas invade the carotid artery, the authors retrospectively reviewed the histopathology of 19 consecutively treated individuals whose carotid artery was sacrificed during removal of a meningioma involving the cavernous sinus. Patients were selected for carotid artery resection based on preoperative magnetic resonance imaging studies demonstrating complete encasement of the artery. Reconstruction of the carotid artery was planned depending on the results of preoperative balloon test occlusion with blood flow determinations. None of the 19 patients had pathological evidence of malignant tumor. Eight individuals (42%) were found to have infiltration of the carotid artery by meningioma. In five cases, focal involvement of the adventitia of the carotid artery wall was noted and, in three, the vessel was infiltrated up to the tunica muscularis. In no case was the tunica muscularis invaded by tumor. Thus, meningiomas of the cavernous sinus do infiltrate the internal carotid artery and, in order to completely resect these lesions and effect a surgical cure, it may be necessary to sacrifice the carotid artery with or without reconstruction.

Gamma knife radiosurgery of meningiomas in the cavernous sinus region

For 6 years (1992-1998) we have treated 67 patients with cavernous sinus meningioma using the Leksell gamma knife in the Hospital Na Homolce, Prague. The age of the patients ranged between 19-82 years, median 57 years. Radiosurgery was the primary treatment in 64.2% of the patients, in the rest a microsurgical resection preceded. The volume of the tumour ranged from 0.9-31.4 cm3, median 7.8 cm3. The meningioma was distant from the optic tract in 58% of the cases, in 12% of the cases there was a contact with the tumour and the optic tract without its compression and in 30% of the cases there was a compression of the optic tract caused by the meningioma. The dose to the tumour margin ranged from 10-14 Gy, median 12 Gy. The follow up was available in 53 patients, in intervals of 2-60 months, median 19 months. There was no change in the tumour volume in 48% of the cases, in 52% of the cases a decrease of the tumour volume occurred. No increase of the tumour volume was observed. Clinical symptoms and signs improved in 35.8% of the patients, temporary morbidity was 3.8%. The mortality of the treatment was zero. Hitherto, the results of gamma knife radiosurgery of cavernous sinus meningioma have proved its safety and efficiency, although long term experience with a large group of patients is missing. Advances in neuroradiology and radiosurgical technique have allowed us to treat tumours with a closer contact to the optic tract and nerves compared with the past.

Pituitary volume and headache: size is not everything

BACKGROUND

Pituitary tumors are commonly associated with disabling headache. The accepted mechanisms for headache are dural stretch and cavernous sinus invasion.

OBJECTIVE

To determine if there is a relationship between pituitary tumor size and the report of headache.

DESIGN

We prospectively studied 63 patients who were initially seen with pituitary tumors. Clinical headache scores, pituitary tumor volume, and the extent of cavernous sinus invasion were obtained for each patient.

RESULTS

The prevalence of headache was 70%. There was no positive correlation the between clinical headache score and pituitary volume (r = -0.32, P =.01, Spearman rank correlation). There was also no association between cavernous sinus invasion and headache. There was a strong association between pituitary-associated headache and a family history of headache (chi(2) = 8.36, P =.004).

CONCLUSIONS

These data suggest that a pituitary tumor-associated headache may not simply be a structural problem. Other factors such as family history of headache, and the endocrine activity of the tumor may be equally important determinants of headache. Elucidating these mechanisms will aid in the treatment of these patients and further our understanding of other headache syndromes.

Suppurative intracranial complications of sinusitis

OBJECTIVES

To familiarize the contemporary surgeon with the pathogenesis, diagnosis, and appropriate management of suppurative intracranial complications of sinusitis.

STUDY DESIGN

Retrospective chart review.

METHODS

All patients admitted to the University of Virginia Health Sciences Center with a diagnosis of intracranial suppuration between 1992 and 1997 were reviewed.

RESULTS

One hundred seventy-six cases were identified, of which 15 patients had 22 suppurative intracranial complications of sinusitis. These were epidural abscess (23%), subdural empyema (18%), meningitis (18%), cerebral abscess (14%), superior sagittal sinus thrombosis (9%), cavernous sinus thrombosis (9%), and osteomyelitis (9%).

CONCLUSIONS

The diagnosis of suppurative intracranial complications of sinusitis requires a high index of suspicion and confirmation by imaging. Central to the success of treatment is the management of the primary source of sepsis within the paranasal sinuses in combination with neurosurgical drainage and intravenous antibiotics. This approach has resulted in a mortality rate of 7% and morbidity of 13%, which compare favorably with previous series.

Clinical characteristics of dural arteriovenous fistula

Intracranial dural arteriovenous fistula (DAVF) is an uncommon neurosurgical condition; in particular, it has been infrequently reported in Korea. To understand the general clinical characteristics of DAVFs, the authors reviewed 53 cases and analyzed factors affecting DAVF hemorrhage of and treatment outcome. Since 1980 we have encountered 480 pial and 53 DAVFs, a ratio of 9.1 to 1. The age of these patients ranged from 1 month to 71 years, the most common being in the 6th decade, and females exceeded males by 1.65 to 1. All lesions except three were single, and symptoms were related to location and the venous drainage pattern. The most common location was the cavernous sinus, accounting for about 64% of cases, with the result that the most common clinical symptoms of DAVFs were ocular, namely proptosis and chemosis. The next was tinnitus also found in transverse-sigmoid sinus DAVFs. Intracranial hemorrhage was seen in eight cases,(15%) the primary cause of hemorrhage was retrograde intracranial venous drainage (P=0.017), and one hemorrhage was observed in cases with no intracranial venous drainage. Intracranial hemorrhage was more frequently in transverse-sigmoid than cavernous sinus DAVFs (P=0.049), and this proved to be so even where there was intracranial venous drainage. However, two of 34 patients with cavernous DAVFs became blind in one eye, demonstrating that in such patients, the clinical course could be aggressive. Thirteen patients were treated conservatively. The conservative treatment group was comprised of 13 patients, two of three patients with transverse-sigmoid sinus DAVF expired, and 7 of 10 with cavernous sinus DAVF experienced a clinical improvement or cure. Surgical excision was performed in only two patients. A total of 39 patients underwent embolization; clinical cure was achieved in 13, improvement of symptoms in 12, an unchanged or aggravated result occurred in 9, one died, and four were lost to follow up. During intervention, there was one hemorrhagic complication, owing to obstruction of the venous outflow with embolic materials. In this study, the most common location of DAVFs was the cavernous sinus. The cortical venous drainage remains the primary determinant of intracranial hemorrhage. Common indications for treatment include hemorrhage and neurological deficit. Endovascular treatment is preferred in the majority of cases except tentorial DAVF. The goal of embolization in cavernous DAVF is the alleviation of symptoms, not angiographic cure. But transverse-sigmoid sinus DAVF with venous restriction and leptomeningeal drainage should be treated aggressively.

Pseudotumor of the orbit. Clinical, pathologic, and radiologic evaluation

Pseudotumor, Graves' disease, and lymphoproliferative disease are the most common ophthalmologic disease entities requiring evaluation by CT and MR imaging. A history of acute onset, pain, swelling, proptosis, and response to steroids are the classical findings. The radiologic findings are categorized according to location into dacryoadenitis, myositis, and sclerouveitis, with and without associated infiltrations. The inflammatory infiltrate, which is composed of polymorphic leukocytes, lymphocytes, and plasma cells interspersed with a variable amount of fibrovascular tissue, may be diffuse or localized. The preferred radiologic method used for assessment of pseudotumor is CT. MR imaging, however, is indicated for evaluation of the Tolosa-Hunt syndrome, which is characterized by an inflammatory infiltrate in the orbital apex and cavernous sinus leading to cranial nerve involvement with ophthalmoplegia. The clinical and radiologic constellation of findings allows a definitive diagnosis in most cases.

Septic thrombosis of the cavernous sinuses

Cavernous sinus thrombosis may occur as a complication of infectious and noninfectious processes. Septic thrombosis of the cavernous sinuses most commonly follows infections of the middle third of the face due to Staphylococcus aureus. Other antecedent sites of infection include paranasal (usually sphenoid) sinusitis, dental abscess and, less often, otitis media. Fever is a nearly constant finding, but headache may not be prominent. Periorbital edema, chemosis, proptosis, and limitation of extraocular movements (especially lateral gaze) develop in almost all recognized cases. Involvement of the opposite eye frequently appears within two days following the onset of unilateral signs. Although computed tomography may be helpful, magnetic resonance imaging is probably the diagnostic procedure of choice. Treatment includes appropriate antibiotics and, oftentimes, surgical drainage of the primary focus of infection. Less than half of the patients recover completely; the mortality rate is approximately 30%.

Evidence of meningioma infiltration into cranial nerves: clinical implications for cavernous sinus meningiomas

Anatomical and biological studies of cavernous sinus meningiomas help us understand the biological heterogeneity of these tumors. The question of whether cavernous sinus meningiomas infiltrate cranial nerves is clinically important because of the effect on treatment planning. In the authors' experience of treating 36 patients with cavernous sinus meningiomas, tumor invasion into a cranial nerve was documented in two patients in whom a cranial nerve was resected during the cavernous sinus dissection. In both patients, histological examination using hematoxylin and eosin and bodian stains showed infiltration of the cranial nerves by a benign meningioma which, to the best of the authors' knowledge, is a condition previously unreported. This histological finding of meningioma invasion into a cranial nerve demonstrates the biological heterogeneity of cavernous sinus meningiomas and raises concern about the invasive character of meningioma. Because not all tumor cells can be identified radiologically or by direct visualization at surgery, occult tumor infiltration predisposes a patient to recurrence despite the best neurosurgical efforts. Evidence of cranial nerve infiltration by meningioma suggests that, in some circumstances, cavernous sinus dissection in the hope of total removal of a meningioma may be futile and, in the long term, may provide no advantage over treatment options with lower morbidity.

Imaging lesions of the cavernous sinus

Our aim was to review the imaging findings of relatively common lesions involving the cavernous sinus (CS), such as neoplastic, inflammatory, and vascular ones. The most common are neurogenic tumors and cavernoma. Tumors of the nasopharynx, skull base, and sphenoid sinus may extend to the CS as can perineural and hematogenous metastases. Inflammatory, infective, and granulomatous lesions show linear or nodular enhancement of the meninges of the CS but often have nonspecific MR imaging features. In many of these cases, involvement elsewhere suggests the diagnosis. MR imaging is sensitive for detecting vascular lesions such as carotid cavernous fistulas, aneurysms, and thromboses.