Clinical Features of Intracranial Dural Arteriovenous Fistulas with Spinal Perimedullary Venous Drainage: Report of Two Cases and Literature Review

Objective

We describe two cases of myelopathy onset due to intracranial dural arteriovenous fistulas (DAVFs) and present a literature review.

Case Presentation

(Case 1) A 44-year-old man with subacute onset myelopathy underwent an MRI and DSA. MRI showed T2-hyperintensity from the medulla oblongata to the cervical spinal cord with vascular flow voids, suggestive of a spinal DAVF. Unexpectedly, cerebral angiography revealed a tentorial DAVF. (Case 2) A 47-year-old man with progressive myelopathy underwent a head and spinal MRI. Head MRI and MRA were considered to be normal. Spinal MRI revealed T2-hyperintensity in the cervical spinal cord without obvious vascular flow voids around the spinal cord. Contrast-enhanced MRI showed a patchy gadolinium enhancement in the same spinal cord region with the enhancement of perimedullary vessels. Although myelitis was initially suspected, subsequently spinal DAVF was suspected because cervical CTA revealed abnormal spinal venous drainage. Unexpectedly, cerebral angiography identified a foramen magnum DAVF.

Conclusion

Regarding unexplained cervical myelopathy, even the absence of spinal cord surface vascular flow voids cannot necessarily exclude venous congestive myelopathy due to the DAVFs. In such cases, the contrast-enhanced MRI and cervical CTA are useful for visualizing abnormal vessels around the brain stem and the cervical spine. Especially, the co-presence of the abnormal vessels around the brain stem can suggest the intracranial DAVFs. Not only spinal DAVFs but also intracranial DAVFs should be considered as the differential diagnoses for venous congestive cervical myelopathy, in which cases cerebral angiography including carotid angiography is essential.

Watch brain circulation in unexplained progressive myelopathy: a review of Cognard type V arterio-venous fistulas

BACKGROUND

Intracranial dural arterio-venous fistulas are pathological anastomoses between arteries and veins located within dural sheets and whose clinical manifestations depend on location and hemodynamic features. They can sometimes display perimedullary venous drainage (Cognard type V fistulas-CVFs) and present as a progressive myelopathy. Our review aims at describing CVFs' variety of clinical presentation, investigating a possible association between diagnostic delay and outcome and assessing whether there is a correlation between clinical and/or radiological signs and clinical outcomes.

METHODS

We conducted a systematic search on Pubmed, looking for articles describing patients with CVFs complicated with myelopathy.

RESULTS

A total of 72 articles for an overall of 100 patients were selected. The mean age was 56.20 ± 14.07, 72% of patients were man, and 58% received an initial misdiagnosis. CVFs showed a progressive onset in 65% of cases, beginning with motor symptoms in 79% of cases. As for the MRI, 81% presented spinal flow voids. The median time from symptoms' onset to diagnosis was 5 months with longer delays for patients experiencing worse outcomes. Finally, 67.1% of patients showed poor outcomes while the remaining 32.9% obtained a partial-to-full recovery.

CONCLUSIONS

We confirmed CVFs' broad clinical spectrum of presentation and found that the outcome is not associated with the severity of the clinical picture at onset, but it has a negative correlation with the length of diagnostic delay. We furthermore underlined the importance of cervico-dorsal perimedullary T1/T2 flow voids as a reliable MRI parameter to orient the diagnosis and distinguish CVFs from most of their mimics.

Case report: Delayed quadriplegia from traumatic carotid cavernous fistula: a rare case with perimedullary venous drainage

Background

Carotid cavernous fistula (CCF) refers to the abnormal arteriovenous communication between the carotid system at the skull base and the sphenoid cavernous sinus, which is caused by trauma in almost 75% of cases. The drainage of venous blood to the spinal cord represents a distinctive mechanism, which is commonly observed in dural arteriovenous fistula (DAVF), and typically manifests clinically as progressive myelopathy. However, it is a rare occurrence in clinical practice that traumatic carotid cavernous fistula (TCCF) causes delayed quadriplegia through perimedullary venous drainage.

Case presentation

We report the case of a 29-year-old male patient who was admitted to the hospital with a sudden onset of headache and quadriplegia. The patient had previously lost his right eye in a traffic accident 5 years ago. Cerebral angiography showed a high-flow direct CCF on the right side, accompanied by obvious drainage of cerebellar and perimedullary veins. We successfully performed coil embolization for the CCF, and the symptoms of the patient gradually improved after the operation. During follow-up at sixth-months, the patient regained the ability to walk independently.

Conclusion

We experienced a rare case of TCCF with quadriplegia. Utilizing coil embolization, we achieved successful improvement in the patient's condition. However, the mechanism and the best treatment of CCF drainage through the perimedullary vein are still unclear. We need to further explore the pathophysiological information of CCF venous drainage.

Congestive myelopathy due to craniocervical junction arteriovenous fistulas mimicking transverse myelitis: a multicenter study on 27 cases

BACKGROUND

The purpose was to clarify diagnostic clues and pitfalls in cranio-cervical junction arteriovenous fistulas (CCJ AVFs) with congestive myelopathy.

METHODS

In a multicenter observational study by the Neurospinal Society of Japan, we described the demographics, clinical courses, imaging findings, and outcomes of consecutive patients with CCJ AVFs presenting with congestive myelopathy between 2009 and 2019.

RESULTS

Twenty-seven patients were included (mean age, 70 years; male, 96%). Progressive symptoms within one day to one month were more common (63%) than chronic symptoms. Myelopathic symptoms were characterized by ascending paralysis beginning from the legs, involving the trunk and arms, and sometimes ending in the brainstem. Fifteen patients (56%) received a misdiagnosis, including acute transverse myelitis. The most common MRI findings were venous congestive edema of the cervical cord (96%) and the brainstem (63%) and surrounding vascular flow voids (100%). The mean extension of congestive edema was 5.5 ± 2.9 vertebral segments. The most common angiographic findings were a dural AVF (78%) at the C1 level (81%) with descending venous drainage (85%). Seven patients (26%) were administered steroids, which resulted in neurological decline in 3. Neurosurgical obliteration of the AVF led to improvements in MRI findings in 75% and a functional status in 67%; however, 44% remained dependent.

CONCLUSIONS

The myelopathy of CCJ AVFs was characterized by acute ascending paralysis in elderly men. A misdiagnosis was common because of the acute presentation due to a longitudinally extensive spinal cord lesion. Dilated vessels on MRI were a key finding for the correct diagnosis. What is already known on this topic? Slowly progressive myelopathy is a well-known symptom that results from impaired spinal venous drainage due to thoracolumbar AVFs. Although cranio-cervical junction arteriovenous fistulas (CCJ AVFs) constitute a treatable cause of congestive myelopathy, detailed information is not currently available due to their rarity. What does this study add? CCJ AVFs often presented with acute ascending myelopathy in elderly men due to a longitudinally extending cervical cord lesion with surrounding flow voids. Steroid pulse therapy was not effective or even harmful to congestive myelopathy, while neurosurgical treatment effectively obliterated AVFs. How might this study affect research, practice or policy? The results obtained revealed diagnostic clues and pitfalls from the largest dataset of patients with CCJ AVFs in a multicenter cohort.

Arteriovenous malformation of the trigeminal nerve root presented with venous congestive edema of the medulla oblongata and upper cervical cord: illustrative case

BACKGROUND

Arteriovenous malformation (AVM) of the trigeminal nerve root (TNR) is a rare subtype of the lateral pontine AVM. Most of them are diagnosed when they bleed or exert trigeminal neuralgia. Venous congestive edema is a rare phenomenon caused by TNR AVMs.

OBSERVATIONS

An 82-year-old man was admitted with progressive limb weakness and dysphasia. Magnetic resonance imaging (MRI) revealed extensive edema of the medulla oblongata and the upper cervical cord with signal flow void at the C3 anterior spinal cord. Vertebral angiography revealed a small nidus fed mainly by the pontine perforating arteries (PPAs). The anterior pontomesencephalic vein (AMPV) was dilated, functioning as the main drainage route. This suggests that venous hypertension triggered the brainstem and upper cervical cord edema. MRI with gadolinium enhancement showed that the nidus was located around the right TNR. Because the nidus sat extrinsically on the pial surface of the right TNR’s base, microsurgical obliteration with minimum parenchymal injury was achieved. Postoperative MRI showed disappearance of the brainstem and cervical cord edema with improved clinical symptoms.

LESSONS

TNR AVM is rarely associated with brainstem and upper cervical cord edema caused by venous hypertension of the congestive drainage system.

A case series of intracranial dural arteriovenous fistulae mimicking cervical myelitis: a diagnosis not to be missed

Objective

To describe the diagnostic features of intracranial dural arteriovenous fistulae (DAVF) presenting with cervical cord or brainstem swelling.

Methods

Retrospective case note and neuroimaging review of patients with angiographically confirmed DAVF diagnosed during January 2015–June 2020 at a tertiary neuroscience centre (Walton Centre NHS Foundation Trust, Liverpool, UK).

Results

Six intracranial DAVF causing cervical cord or brainstem oedema (all males aged 60–69 years) and 27 spinal DAVF (88% thoracolumbar) were detected over a 5.5-year period. Significantly more patients with intracranial DAVF received steroids for presumed inflammatory myelitis than those with spinal DAVF (5/6 vs 1/27, p = 0.0001, Fisher’s exact test). Several factors misled the treating clinicians: atypical rostral location of cord oedema (6/6); acute clinical deterioration (4/6); absence (3/6) or failure to recognise (3/6) subtle dilated perimedullary veins on MRI; intramedullary gadolinium enhancement (2/6); and elevated CSF protein (4/5). Acute deterioration followed steroid treatment in 4/5 patients. The following features may suggest DAVF rather than myelitis: older male patients (6/6), symptomatic progression over 4 or more weeks (6/6) and acellular CSF (5/5).

Conclusion

Intracranial DAVF are uncommon but often misdiagnosed and treated as myelitis, which can cause life-threatening deterioration. Neurologists must recognise suggestive features and consider angiography, especially in older male patients. Dilated perimedullary veins are an important clue to underlying DAVF, but may be invisible or easily missed on routine MRI sequences.

Arteriovenous Fistula at the Craniocervical Junction Found After Cervical Laminoplasty for Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is common in East Asia. Arteriovenous fistula at the craniocervical junction (CCJ-AVF), in contrast, is rare. As OPLL occurs most often in the cervical region, these 2 conditions can coexist in the cervical spinal canal of a single patient. We report a case of CCJ-AVF found after cervical laminoplasty (CLP) for OPLL. A 68-year-old man experienced progressive myelopathy due to cervical OPLL. Magnetic resonance imaging (MRI) revealed a high-intensity area inside the spinal cord. CLP was performed and his symptoms immediately improved. Three months after CLP, however, myelopathy recurred. MRI revealed an exacerbated and enlarged high-intensity area inside the cord from the medulla oblongata to the C4/5 level with a flow void around the cord. Left vertebral artery angiography revealed CCJ-AVF with ascending and descending draining veins. Direct surgery was performed to interrupt shunt flow into the draining veins. The patient’s symptoms improved to a limited degree. In this case, increased pressure inside the spinal canal due to OPLL might have decreased the shunt flow of the CCJ-AVF. Thus, the venous congestion induced by CCJ-AVF might have been exacerbated after the pressure was removed by CLP. Magnetic resonance angiography screening could help detect concurrent CCJ-AVF and OPLL.

Intracranial Dural Arteriovenous Fistulas With Brainstem Engorgement: An Under-Recognized Entity in Diagnosis and Treatment

Background: In rare circumstances, patients with intracranial (dural arteriovenous fistulas) DAVFs could be complicated with brainstem engorgement, which might lead to delayed or false diagnosis and subsequent improper management.

Methods: On July 2th, 2019, a systematic search was conducted in the PubMed database for patients with intracranial DAVFs complicated with brainstem engorgement.

Results: Sixty-eight articles reporting of 86 patients were included for final analysis. The patients were aged from 20 to 76 years (57.10 ± 12.90, n = 82). The female to male ratio was 0.68 (35:51). Thirty-three (40.2%, 33/82) patients were initially misdiagnosed as other diseases. The specific location distributions were cranio-cervical junction, cavernous sinus, superior petrosal sinus, transverse and/or sigmoid sinus, tentorium, and other sites in 27 (32.5%), 11 (13.2%), 9 (10.8%), 10 (12.0%), 21 (25.3%), and 5 (6.0%) patients, respectively. The Cognard classification of DAVFs were II, III, IV, and V in 9 (10.7%, 9/84), 1 (1.2%, 1/84), 1 (1.2%, 1/84), and 73 (86.9%, 73/84) patients. Eighteen (22%, 18/82) patients were demonstrated to have stenosis or occlusion of the draining system distal to the fistula points. The mean follow-up period was 7.86 (n = 74, range 0–60 months) months. Fifty-four (70.1%, 54/77) patients experienced a good recovery according to the mRS score.

Conclusions: Intracranial DAVFs complicated with brainstem engorgement are rare entities. Initial misdiagnosis and delayed definite diagnosis are common in the past three decades. The treatment outcome is still unsatisfactory at present. Early awareness of this rare entity and efficiently utilizing the up to date investigations are of utmost importance.

A rare case of spinal dural arteriovenous fistula mimicking malignant glioma of the medulla oblongata: Significance of cerebral angiography for accurate diagnosis of brain stem region

Background:

The findings of a hyperintense sign on T2-weighted imaging (T2-WI) and gadolinium (Gd) contrast enhancement on magnetic resonance imaging (MRI) of the brain stem suggest malignant glioma. However, this pathological condition is probably uncommon, and it may be unknown that a dural arteriovenous fistula (DAVF) can imitate this radiological pattern. In addition, it is extremely rare to be caused by a spinal DAVF. Here, a rare case of spinal DAVF that mimicked malignant glioma of the medulla oblongata is presented.

Case Description:

A 56-year-old woman was admitted with a progressive gait disturbance, vertigo, and dysphasia. MRI showed a hyperintense signal in the medulla oblongata on fluid-attenuated inversion recovery (FLAIR) and moderate contrast enhancement on Gd-enhanced MRI. Interestingly, Gd-enhanced MRI demonstrated abnormal dilated veins around the brain stem and cervical spinal cord. Cerebral angiography showed spinal DAVF at the left C4/C5 vertebral foramen fed by the C5 radicular artery. The fistula drained into spinal perimedullary veins and flowed out retrograde at the cortical vein of the posterior cranial fossa. Therefore, surgical disconnection of the spinal DAVF was performed by a posterior approach. The patient’s postoperative course was uneventful. Cerebral angiography showed complete disappearance of the DAVF, with marked reductions of the hyperintense sign of the medulla oblongata on FLAIR.

Conclusion:

This important case illustrates MRI findings mimicking brain stem glioma. In cases with the hyperintense sign-on T2-WI associated with contrast enhancement suspicious of brainstem glioma, careful checking for perimedullary abnormal vessels and additional cerebral angiography should be performed.

Medullary Hemorrhage Caused by Foramen Magnum Dural Arteriovenous Fistula Successfully Obliterated using Combination of Endovascular and Surgical Treatments: A Case Report and Literature Review

The authors describe an extremely rare case of foramen magnum dural arteriovenous fistula (DAVF), Cognard type V, presented with medullary hemorrhage caused by venous varix on the lateral medullary draining vein embedded into the medulla oblongata. Following mild myelopathy for 3 days, a 20-year-old male developed dyspnea, generalized seizures, loss of consciousness, and finally cardiac arrest. After successful resuscitation, computed tomography scan (CT) of the brain was obtained and showed acute medullary hemorrhage. Subsequent magnetic resonance imaging of the brain revealed diffuse venous congestion or edema of the medulla with multiple dilated flow voids surrounding the medulla, more prominent on the left side, with venous varix embedded into the left-sided of the lower medulla. He was sent to the emergency department of the local hospital and intubated promptly. A few minutes later, the patient had a cardiac arrest. Digital subtraction angiography (DSA) demonstrated DAVF of the foramen magnum supplied mainly by dural branches of bilateral hypertrophic posterior inferior cerebellar arteries (PICAs), slightly by the posterior meningeal branch of the left vertebral artery, and the jugular branch of the left ascending pharyngeal artery (APA) originating from the occipital artery. Transarterial embolization through the bilateral dural branches of the PICAs was successfully performed using N-butyl-2-cyanoacrylate (NBCA), resulting in complete obliteration. The patient had excellence recovery and lost to annual follow-up. Seven years later, he had a recurrent of the fistula presented with occipital headache. DSA with angiographic CT in three-dimensional reconstruction and maximum intensity projection reformatted images clearly demonstrated the exact location of the DAVFs at the posterior rim of the foramen magnum, mainly recruited by the hypertrophic jugular branch of the APA originating from the occipital artery. The fistula was successfully treated surgically following transarterial embolization through the jugular branch of the APA using NBCA. Follow-up DSA confirmed complete obliteration of the DAVF. The patient has remained clinically asymptomatic 2 years after the operation.

Spontaneous Closure of a Cavernous Sinus Dural Arteriovenous Fistula with Spinal Perimedullary Drainage (Cognard V) during Attempted Transvenous Embolization

The authors describe a patient with spontaneous closure of a spontaneous cavernous sinus dural arteriovenous fistula (CSDAVF), Cognard type V, during transvenous attempt. A 39-year-old woman experienced mild proptosis, redness of the left eye, and diplopia. Four months later, she developed left retro-orbital pain and left-sided headache. Cerebral angiography revealed the left CSDAVF exclusively draining into the superior petrosal sinus with subsequent drainage into the veins surrounding the medulla oblongata, and finally into the perimedullary spinal veins, classified as Cognard type V. The feeders arise from the dural branches of both the left external and internal carotid arteries. Following 2 h period of attempted transvenous embolization, the fistula disappeared spontaneously. Follow-up angiography obtained 6 months later confirmed complete resolution of the CSDAVF. At 2-year follow-up, the patient has remained clinically asymptomatic. The mechanism of thrombosis in this fistula related to the endovascular procedure. We speculated that putting the wire tip in the draining vein may induce the spontaneous thrombosis in the venous side. In addition, precipitating factors may include small, low-flow fistula, and pre-existing thrombosis.

An Isolated Unilateral Pontomedullary Lesion Due to An Intracranial Dural Arteriovenous Fistula Mimicking A Brain Tumor - Case and Review

Intracranial dural arteriovenous fistula (DAVF) with perimedullary venous drainage may cause brainstem swelling and represent a diagnostic challenge. A 66-year-old man presented to the emergency room with recurrent vertigo, minimal truncal ataxia with a wide-based gait, and a slightly impaired tandem gait. Brain magnetic resonance imaging (MRI) revealed a hyperintense lesion in the left pontomedullary area on T2-weighted images (T2WIs) with partial gadolinium enhancement, but without increased signals on diffusion-weighted images. Abnormal serpentine flow void vessels surrounding the medulla and upper cervical spinal cord were initially overlooked but discovered later. An angiogram revealed DAVF with feeders from the right occipital artery and the meningeal branch of the right distal vertebral artery with drainage into the anterior medullary venous system and the perimedullary veins. The patient underwent a successful transarterial endovascular embolization and improved gradually. A brain MRI at 3-month follow-up revealed a residual hyperintense signal on the T2WIs in the left lower medulla. Six cases of patients exhibiting DAVF with isolated unilateral brainstem swelling from the literature were reviewed. Isolated unilateral brainstem swelling due to intracranial DAVF with perimedullary venous drainage is extremely rare and might mimic a tumor on MRI. Abnormal serpentine flow void vessels on the surface of the brainstem or spinal cord are crucial diagnostic clues.

Lumbar tap-induced subarachnoid hemorrhage in a case of spinal epidural arteriovenous fistula

The authors report the case of a 70-year-old woman with lumbar spinal epidural arteriovenous fistula (SEDAVF) who experienced subarachnoid hemorrhage (SAH) after a diagnostic lumbar puncture. According to the literature, perimedullary spinal vein enlargement is a hallmark of spinal vascular diseases; however, there are certain cases in which routine sagittal MRI fails to disclose signal flow voids. In such cases, patients may undergo a lumbar tap to investigate the possible causes of spinal inflammatory or demyelinating disease. Recognizing this phenomenon is essential because lumbar puncture of the epidural venous pouch or an enlarged intradural vein in SEDAVF may induce severe SAH. A high clinical index of suspicion can prevent similar cases in lumbar SEDAVF.

Lessons to Be Remembered from a Dural Arteriovenous Fistula Mimicking Medulla and High Cervical Cord Glioma

The radiological signs of intracranial dural arteriovenous fistulas (ICDAVFs) are heterogenous. While it is commonly accepted that hyper intense T2 wedge magnetic resonance imaging of the brainstem and cervical cord mainly concern gliomas, it is so far uncommon and probably unknown that ICDAVFs can imitate similar radiological pattern, especially with gadolinium contrast enhancement and cord enlargement. Thus the angiography is poorly documented in the diagnostic workup. We report the unusual history of ICDAVFs, revealed by clinical and radiological features that mimicked a medulla or cervical spinal cord glioma. This observation provides information on the management of atypical lesions mimicking medulla or cervical cord glioma and arguments for a careful radiological study. Looking for dilated veins around the brainstem and the cord is mandatory in the workup of a supposed infiltrating brainstem or spinal cord lesion, in order to rule out an ICDAVF. Even if the hyperintense T2 images associated with contrast enhancement is in favor of a brainstem or spinal cord glioma, additional cerebral angiography should be mandatory. Moreover, this clinical case highlights the need for a multidisciplinary approach including neuroradiologist, oncologist and neurosurgeon.

Dural Arteriovenous Fistulas: A Characteristic Pattern of Edema and Enhancement of the Medulla on MRI

Medullary edema with enhancement is rarely reported at initial MR imaging in intracranial dural arteriovenous fistulas. We report a series of 5 patients with dural arteriovenous fistulas, all of whom demonstrated a characteristic pattern of central medullary edema and medullary enhancement at initial MR imaging. Cognard type V dural arteriovenous fistula, defined by drainage into the perimedullary veins and the veins surrounding the brain stem, is a rare yet well-described pathologic entity. Even more rarely reported, however, is its clinical presentation with predominantly bulbar symptoms and MR imaging findings of central medullary edema with enhancement. This constellation of findings frequently leads to a convoluted clinical picture, prompting work-up for alternative disease processes and delaying diagnosis. Because an expedited diagnosis is critical in preventing poor outcomes, it is paramount to make the referring physician and neuroradiologist more cognizant of this rare-yet-characteristic imaging manifestation of dural arteriovenous fistula.

Transarterial Onyx embolization of jugular foramen dural arteriovenous fistula with spinal venous drainage manifesting as myelopathy-a case report and review of the literature

We report a rare case of jugular foramen dural arteriovenous fistula (DAVF) with spinal venous drainage. A 48-year-old woman suffered from progressive weakness of lower extremities and incontinence of urine and feces for 14 days. Magnetic resonance imaging (MRI) revealed a tortuous posterior medullary vein at C2-T2 and ischemic signal at C2-C4 of the spinal cord. Brain MRI revealed an abnormal high signal near the left jugular foramen. Digital subtraction angiography of the spinal vascular was negative, while brain angiography showed a left jugular foramen DAVF with spinal perimedullary venous drainage. The patient recovered completely soon after endovascular embolization with Onyx-18. Diagnosis of a DAVF presenting with myelopathy is challenging. Early diagnosis and treatment are essential for a favorable outcome.

Diagnosis and management of intracranial dural arteriovenous fistulas

Dural arteriovenous fistula (DAVF) is a rare type of acquired intracranial vascular malformation. Recent progress in neuroimaging technology, such as advanced MRI and CT, provides non-invasive methods to accurately diagnose DAVF, including evaluation of the hemodynamics of the drainage veins. The clinical manifestations of DAVFs vary widely and depend on the location and venous drainage pattern of arteriovenous shunting. Patients with high grade DAVFs having cortical venous reflux should receive aggressive treatment to prevent the occurrence of intracranial hemorrhage and other neurological deficits related to venous congestion. Intra-arterial or intravenous endovascular embolization remains the primary therapy for high grade DAVF, while open surgery and stereotactic radiosurgery can serve as alternative treatment options. Early and accurate diagnosis with appropriate treatment is the goal for clinical management of DAVFs to reduce symptoms and prevent the development of venous congestion and stroke.

Unilateral contrast-enhancing pontomedullary lesion due to an intracranial dural arteriovenous fistula with perimedullary spinal venous drainage: the exception that proves the rule

A large spectrum of possible diagnoses must be taken into consideration when a contrast-enhancing lesion of the pontomedullary region is found on MRI. Among these diagnoses are neoplastic, inflammatory, and infectious, as well as vascular pathologies. The authors report a rare case of an intracranial dural arteriovenous fistula (DAVF) with perimedullary spinal venous drainage (Cognard Type V) that initially presented as a unilateral contrast-enhancing pontomedullary lesion mimicking a brainstem neoplasm in a 76-year-old man. Following occlusion of the DAVF by transarterial embolization that resulted in clinical and radiological improvement, the fistula recurred 10 months later and was finally cured by a combined endovascularand surgical approach that resulted in complete occlusion. Clinical symptoms and MRI findings gradually improved following this treatment. A literature review on the MRI findings of Cognard Type V DAVF was performed. Centrally located medullary or pontomedullary edema represents the typical imaging finding, while unilateral edema as seen in the authors’ patient is exceptionally rare. The hallmark imaging finding suggestive of DAVF consisting of perimedullary engorged vessels may not always be present or may only be very subtly visible. Therefore, the authors suggest performing contrast-enhanced MR angiography or even digital subtraction angiography in the presence of an unclear edematous brainstem lesion before scheduling stereotactic biopsy.

Dural Arteriovenous Fistula of the Transverse and Sigmoid Sinus Manifesting Ascending Dysesthesia: Case Report and Literature Review

Cases involving intracranial dural arteriovenous fistulas (AVFs) with spinal perimedullary venous drainage exhibit variable presentations, which results in delayed diagnoses. We describe a case of a 66-year-old female with a transverse-sigmoid sinus dural AVF with spinal perimedullary venous drainage who developed dysesthesia and hypalgesia that ascended from the peripheral lower extremities. Sixty cases of intracranial dural AVFs resulting in myelopathy have been reported, and an absence of brainstem signs significantly correlated with a delay in diagnosis (positive group: 3.4 months vs. negative group: 9.6 months, P < 0.05). Intracranial dural AVFs with brainstem signs should be diagnosed without delay because the myelopathy and bulbar symptoms could progress aggressively without alternative drainage routes besides the perimedullary veins. We emphasize that intracranial dural AVFs should be considered as a differential diagnosis in case presenting with symptoms, such as atypical dysesthesia and hypalgesia ascending from the toes, without brainstem signs. Moreover, we should perform cerebral angiography as early as possible because dural AVFs with slow-flow venous drainage can produce false negatives on magnetic resonance angiography.