PDF revista.pdf Spinal intradural arteriovenous �stula mimicking intramedullary tumor and associated with a giant intracranial aneurysm Wuilker Knoner Campos1, Benjamin Franklin da Silva2, Jose Antônio Damian Guasti3 ABSTRACT Spinal intradural arteriovenous !stulas (AVFs) are a rare type of neurovascular malformation. Many a time hemodynamic disturbs associated to these entities can cause edema with subsequent myelopathy. On MRI study, this edema can mimic an intramedullary tumor. We report a rare case of spinal intradural AVFs mimicking an intramedullary tumor, which also were surprisingly associated with a giant intracranial aneurysm. We highlight in detail the MRI !ndings in intramedullary lesions, and also emphasize that these entities requires as careful differential diagnosis as supplementary investigation of the neuroaxis looking for other simultaneous neurovascular pathologies. KEY-WORDS Arteriovenous !stula, vascular malformations, spine, intracranial aneurysm, spinal cord/pathology. RESUMO Fístula arteriovenosa intradural espinhal mimetizando tumor intramedular e associado com aneurisma intracraniano gigante Fístulas arteriovenosas espinhais intradurais são um tipo raro de malformação neurovascular. Muitas vezes, distúrbios hemodinâmicos associados a essa entidade podem causar edema com subsequente mielopatia. Em estudos de ressonância magnética, esse edema pode mimetizar um tumor intramedular. Relata-se um caso raro de !stula arteriovenosa espinhal intradural mimetizando um tumor intramedular, que também estava associado a um aneurisma cerebral gigante. Destacam-se em detalhes os achados de RM nas lesões intramedulares, assim como se enfatiza que essas entidades requerem tanto um diagnóstico diferencial criterioso quanto uma investigação complementar do neuroeixo procurando por outras patologias neurovasculares associadas. PALAVRAS-CHAVE Fístula arteriovenosa, malformações vasculares, coluna vertebral, aneurisma intracraniano, medula espinhal/patologia. 1. Neurosurgeon, NEURON Institute of Neurosurgery, Baía Sul Hospital, Florianópolis, SC, Brazil, associate professor, Division of Neurosurgery, Federal University of Santa Catarina, Florianópolis, SC, Brazil. 2. Assistant neurosurgeon, Department of Neurosurgery, Bonsucesso Federal Hospital, Rio de Janeiro, RJ, Brazil. 3. Head, Department of Neurosurgery, Bonsucesso Federal Hospital, Rio de Janeiro, RJ, Brazil. Introduction Intradural spinal arteriovenous !stulas (AVFs), a subtype of spinal vascular malformation, are a direct communication between a spinal artery and a vein on the spinal cord surface or in the subarachnoid space. Spinal vascular malformations are a heterogeneous group of rare and still underdiagnosed pathological entities that classically may lead to progressive mye- lopathy if not early diagnosed and treated.4,8 Magnetic resonance imaging (MRI) is considered the !rst-line diagnostic modality of choice in progressive myelo- pathy. However, despite high-resolution of this exam, care must be taken not to fall into the image’s pitfall of these entities. Spinal cord infarction related to spinal AVFs may mimic an intramedullary tumor, leading even expert physicians to make mistake of diagnosis. Moreo- ver, other vascular malformations may be associated to AVFs in the nervous system. We report a rare case of spinal intradural AVFs mimicking an intramedullary tumor, which were surprisingly associated with a giant intracranial aneurysm. Arq Bras Neurocir 30(4): 199-202, 2011 200 Case report History A 62-year-old Caucasian woman was referred to our hospital complaining of low-back pain for 4 years associated to a progressive lower-extremity weakness and intermittent urinary incontinence over the past 2 years. At the time of presentation the patient has exhib- ited paraplegia for 2 months. "ere was no history of trauma or orthopedic deformities. Examination In additional paraplegia on neurological examina- tion, we also found a bilateral anesthesia with sensitivity level at D11 dermatome, proprioceptive sensory de!cit of the lower limbs, bilaterally Babinski`s sign, bladder dysfunction, and tendon re#exes were increased in the lower extremities. Unexpectedly, an unclear Ho$mann’s sign in right upper extremity was found. Spine MRI !ndings have demonstrated an intramedullary lesion at D11-L1 levels Figures 1 A and B, but no changes in cervical spine. An intramedullary tumor (astrocytoma or ependymoma) had been suggested by neuroradi- ologists. Neurosurgical team agreed to this reasonable hypothesis and then surgical procedure was proposed to the patient. As cervical spine was no changes and Ho$mann’s sign was uncertain, we did not consider this sign like an objective physical !nding. Operation It was performed a posterior operative approach with a D10-L1 laminectomy. As soon as we had opened the dura-matter, it was unexpectedly found a numerous serpiginous vessels with medium caliber that covered posterior and lateral surface of cord extending at the conus medullaris without radicular prolongations. "ese lesions compressed slightly the medulla, which presented pallidal and tumescent aspect (Figure 2). We did not observe nidus. On immediately transoperative reanalysis of the spine MRI, we found multiple signal voids dots in subarachnoid space (Figure 1 C). Subse- quently, microsurgical ligature of !stula with a dorsal venous plexus resection was successful performed. Postoperative course Initially, the patient reported a discreet improve- ment of the strength in the le% leg, but not functional (muscle strength grade I). Because of the initial unva- lu ed Ho$mann’s signs and the transoperative !ndings, the remaining neuroaxis was investigated through Figure 2 – Intraoperative photograph: It observes tortuous and dilated vessels with serpiginous aspect on the posterior surface of the cord. In addition to venous out!ow obstruction (not shown), arterialization of these veins produces venous hypertension. Nidus was not observed. Figure 1 – Image’s Studies: "oracolumbar spine MRI (A, B, C) of spinal intradural AVFs showing an intramedullary edema (white arrow) mimicking a tumor at D11-L1 levels. (A) Sagittal T1-weighted image and (B) Sagittal FLAIR sequence show a lesion with signal hyperintensity without spinal cord contrast enhancement, making it di#cult to di$erentiate from other entities such as intramedullary tumors. (C) Axial T2-weighted MRI shows multiple intradural vessels with !ow voids in dorsal and lateral subarachnoid space (white arrows). (D) Cerebral digital angiography showing a giant aneurysm in the le% MCA. angiography and magnetic resonance. Cerebral digital angiography showed a giant aneurysm in the le% middle cerebral artery (MCA) that was opted for conservative treatment according to the patient`s desire (Figure 1 D). During the follow-up period (40 months) the patient has reported lower limbs improvement with muscle strength recovered to grade III. "e intracranial giant aneurysm has continued no change on angiography, and the patient has not presented new neurological !ndings. Intradural arteriovenous !stula Campos WK, et al. Arq Bras Neurocir 30(4): 199-202, 2011 201 Discussion According to Spetzler classi!cation, spinal cord arteriovenous lesions are divided into arteriovenous !s- tulas (AVFs) and arteriovenous malformations (AVMs). Arteriovenous !stulas are subdivided into those that are extradural and those that are intradural, with intradural lesions categorized as either dorsal or ventral.4,8 Spinal intradural AVFs are uncommon lesions characterized by a direct arteriovenous shunt between a radiculome- dullary artery or radiculopial and perimedullary veins located on the pial surface of the spinal cord and are usually considered to be congenital in origin.8 However, case report of the acquired spinal intradural AVFs has been published.3 "e anatomical distribution of the !stula along the long axis of the spine is bimodal, predominantly in the tho- racolumbar region (particularly at the conus medullaris) as seen in present case and, to a lesser extent, in the upper cervical region. Males and females are equally a$ected.4,8 Clinically, the patients usually present with progres- sive myelopathy due to venous hypertension-induced.4 Venous hypertension leads to swelling and edema into the spinal cord, the so-called state of venous congestion. It occurs in conjunction with the characteristic symp- toms of a slowly progressive neurological deterioration. Most patients, regardless of which type of lesion they harbor, present with myelopathy (80%) but no hemor- rhage. Paraplegia is gradually progresses within 5 years of symptom onset. More rarely, patients have urinary, bowel, or sexual dysfunction.5 MRI is considered the !rst-line diagnostic modality of choice in progressive myelopathy. Findings on MRI study, such as signal abnormalities and cord enlargement are o%en non-speci!c and may result from a variety of pathologic processes in the spinal cord, including tumor, infection, and vascular diseases. "erefore, edema due to intramedullary venous congestion represents really a pitfall because can be misdiagnosed as an intramedul- lary tumor Figures 1 A and B.9 However, an apparently normal MRI study does not exclude a vascular lesion as the cause of clinical signs of myelopathy. Consequently, it is very important to know the patterns of spinal cord lesions on MRI for the di$erential diagnosis2 (Table 1). "e characteristic MRI !ndings of spinal intradural AVFs are extramedullary intradural alterations such as dilated vessels with multiple signal voids (Figure 1 C) or subarachnoid hemorrhages.5 When a spinal vascular malformation is suspected based on MRI and neurologi- cal symptoms, selective spinal angiography should be conducted in order to determine the type (AVM or AVF) and #ow (high or low) of the vascular malformation, be- sides helping to determine the appropriate treatment.10 Spinal intradural AVFs can be treated with surgery, embolization, or both. Authors agree that surgery is optimum for two reasons. First, the embolization is associated with a high risk of occlusion of the anterior spinal artery or its branches7 and the rates of recurrence and progressive myelopathy associated with emboliza- tion are high. Second, according to surgical series, the reported morbidity rate is extremely low and the suc- cess rate high.6 Table 1 – Common MRI patterns with di$erential diagnosis of the intramedullary lesions Signal Contrast enhancement Hypotesis Pattern 1 Abnormal signal intensity on T2-weighted images Focal solid enhancement Tumor (ependymoma, hemangioblastoma, metastasis, astrocytoma, lymphoma) Myelitis Infarction Pattern 2 Abnormal signal intensity on T2-weighted images Nonsolid enhancement Tumor (astrocytoma, ependymoma, lymphoma) Infarction, spinal AVF* Myelitis Pattern 3 Hyperintensity on T2-weighted images No Myelitis Infarction, spinal AVF* Tumor (astrocytoma) Others Pattern 4 Mixed hypointense and hyperintense signal abnormalities on T1-weighted and T2-weighted images __ Hemorrhagic tumors (astrocytoma, ependymoma, metastasis) Cavernous hemangioma, spinal AVF* Posttraumatic hemorrhagic contusion Pattern 5 Hyperintense and inhomogeneous lesion Leptomeningeal enhancement Tumor (Metastasis, lymphoma, leukemia) Myelitis Pattern 6 Di$use atrophy of the spinal cord with or without abnormal signal intensity No Hereditary (adrenoleukodystrophy, hereditary ataxia with cord degeneration) Others (multiple sclerosis, AIDS vacuolar myelopathy and tract pallor, amyotrophic lateral sclerosis, posttraumatic atrophy) *AVF: arteriovenous !stula. Intradural arteriovenous !stula Campos WK, et al. Arq Bras Neurocir 30(4): 199-202, 2011 202 "e common association between arteriovenous malformations in tandem with aneurysms (and vice versa) in the nervous system is well known and suggests that hemodynamic stress is the signi!cant factor in the development of both lesions when found simultane- ously. However in our case we found two neurovascular lesions in uncorrelated site. "us, although increased blood #ow seems to be an important factor in forma- tion of these aneurysms associated with AVMs, the role of a developmental vascular anomaly also must be hypothesized.1 To the authors’ knowledge, the associa- tion of these two concurrent vascular lesions has not been previously reported. Conclusion In conclusion, MRI !ndings of spinal intradural AVF may be misdiagnosed as intramedullary tumor because of edema associated to intramedullary venous congestion. Cases as seen in present study require care- ful di$erential diagnosis from intramedullary lesions. "e present study also emphasizes the role of neurologi- cal exam, and that even an unclear sign can represent an important pathology requiring further investigation. Spinal intradural AVFs in association with giant intra- cranial aneurysm have not been previously reported. Whether this concurrence is purely a coincidence or whether there is a pathogenetic link between them cannot be answered. References 1. Biondi A, Merland JJ, Hodes JE, Pruvo JP, Reizine D. Aneurysms of spinal arteries associated with intramedullary arteriovenous malformations. I. Angiographic and clinical aspects. AJNR Am J Neuroradiol. 1992;13(3):913-22. 2. Bourgouin PM, Lesage J, Fontaine S, Konan A, Roy D, Bard C, et al. A pattern approach to the differential diagnosis of intramedullary spinal cord lesions on MR imaging. AJR Am J Roentgenol. 1998;170(6):1645-9. 3. Cho JH, Ahn JY, Kuh SU, Chin DK, Yoon YS. Acquired spinal extradural arteriovenous �stula after instrumented lumbar surgery. Case illustration. J Neurosurg Spine. 2008;9(1):83. 4. Kim LJ, Spetzler RF. Classi�cation and surgical management of spinal arteriovenous lesions: arteriovenous �stulae and arteriovenous malformations. Neurosurgery. 2006;59(5 Suppl 3):S195-201. 5. Koenig E, Thron A, Schrader V, Dichgans J. Spinal arteriovenous malformations and fistulae: clinical, neuroradiological and neurophysiological �ndings. J Neurol. 1989;236(5):260-6. 6. Lee TT, Gromelski EB, Bowen BC, Green BA. Diagnostic and surgical management of spinal dural arteriovenous �stulas. Neurosurgery. 1998;43(2):242-6. 7. Meisel HJ, Lasjaunias P, Brock M. Modern management of spinal and spinal cord vascular lesions. Minim Invasive Neurosurg. 1995;38(4):138-45. 8. Mourier KL, Gobin YP, George B, Lot G, Merland JJ. Intradural perimedullary arteriovenous �stulae: results of surgical and endovascular treatment in a series of 35 cases. Neurosurgery. 1993;32(6):885-91. 9. Roccatagliata L, Centanaro F, Castellan L. Venous congestive myelopathy in spinal dural arteriovenous �stula mimicking neoplasia. Neurol Sci. 2007;28(4):212-5 10. Touho H, Karasawa J, Ohnishi H, Yamada K, Shibamoto K. Superselective embolization of spinal arteriovenous malformations using the Tracker catheter. Surg Neurol. 1992;38(2):85-94. Correspondence address Wuilker Knoner Campos Instituto de Neurocirurgia NEURON, sala 419 – Baía Sul Medical Center Rua Menino Deus, 63 88020-210 – Florianópolis, SC, Brazil Telefax: (+55 48) 3224-0843 E-mail: wuilker@yahoo.com.br Arq Bras Neurocir 30(4): 199-202, 2011 Intradural arteriovenous !stula Campos WK, et al.