Glioblastoma with pseudo-arteriovenous malformation features: Combined arterial spin-labeling assessment and preoperative embolization

Abstract

Background:

Glioblastoma (GBM) may occasionally present with prominent vascular features that mimic an arteriovenous malformation (AVM), leading to diagnostic and therapeutic challenges. Pseudo-AVM GBMs are rare, and their recognition is essential to avoid misdiagnosis and inappropriate management.

Case Description:

We report a 67-year-old male with a 2-month history of progressive headache, memory impairment, and speech difficulties. Neurological examination demonstrated mild right-sided limb weakness, homonymous hemianopsia, and expressive aphasia. Brain magnetic resonance imaging (MRI), computed tomography angiography, and digital subtraction angiography revealed a left temporal GBM with AVM-like vascular features. Arterial spin labeling (ASL) perfusion MRI revealed marked hyperperfusion and early venous drainage, providing noninvasive confirmation of tumor-related shunting. To reduce intraoperative bleeding risk, partial preoperative embolization of feeding arteries from the middle cerebral artery was performed, followed by gross total microsurgical resection. Histopathological examination demonstrated a hypervascular GBM, isocitrate dehydrogenase (IDH)-wildtype, with microvascular proliferation and necrosis confirmed by immunohistochemistry and polymerase chain reaction. Postoperative recovery was uneventful, and adjuvant chemoradiation according to the Stupp protocol was recommended.

Conclusion:

This case highlights pseudo-AVM GBM as a diagnostic and therapeutic challenge and demonstrates the value of ASL perfusion MRI and presurgical embolization in selected hypervascular tumors.

INTRODUCTION

Glioblastoma (GBM, World Health Organization, Central Nervous System grade 4) is the most aggressive adult primary brain tumor. It is usually recognized on magnetic resonance imaging (MRI) by its irregular ring-enhancement, central necrosis, and peritumoral edema. In rare cases, however, its appearance is dominated by vascular features that closely resemble an arteriovenous malformation (AVM), creating what has been termed a pseudo-AVM.[4,9] This phenomenon can mislead diagnosis and complicate management.[5,9] Therefore, such cases represent a diagnostic pitfall with important therapeutic implications,[4,9,13] since the management of AVM differs fundamentally from that of GBM.

MRI plays a central role in the diagnosis, characterization, and treatment planning of GBM.[17] Beyond conventional sequences, advanced MRI techniques provide additional information on tumor physiology, vascularity, and cellularity, thereby improving lesion characterization and surgical planning.[19] Among these techniques, arterial spin-labeling (ASL) enables noninvasive quantification of cerebral blood flow (CBF) without the need for exogenous contrast agents.[12] ASL has been increasingly applied in neurooncology to assess tumor perfusion, differentiate tumor grades, and identify hypervascular components.[10,12] In addition, ASL has demonstrated utility in the evaluation of arteriovenous shunting, further highlighting its potential value in assessing highly angiogenic tumors and complex vascular phenotypes.[15]

From a therapeutic perspective, hypervascular brain tumors pose a substantial surgical challenge because of the risk of excessive intraoperative bleeding.[19] In selected cases, presurgical endovascular embolization has been used to reduce tumor vascularity and facilitate safer resection.[8] Although this approach is well established for certain extra-axial tumors such as meningiomas,[2] its application in GBM remains uncommon and has been reported only in isolated cases of extreme tumor hypervascularity.[8]

By presenting this case, we aim to expand awareness of pseudo-AVM GBM as a diagnostic pitfall, illustrate the value of ASL in detecting tumor-associated vascular shunting, and share our experience with a combined endovascular and surgical strategy that may be applicable in selected patients.

CASE REPORT

A 67-year-old man was admitted to our hospital in September 2025 with progressive headache, memory impairment, and speech difficulties. Symptoms had progressively evolved over a 2-month period. There was no family history of neurological disease and no prior history of trauma or vascular malformation. Neurological examination demonstrated mild right-sided limb weakness (Medical Research Council grade 4/5), homonymous hemianopsia, and expressive aphasia. Fundoscopic examination revealed bilateral papilledema. Based on the subacute progression of symptoms and focal neurological deficits, the initial differential diagnosis included brain tumor, subacute cerebral infarction, and, less likely, an inflammatory process. Given these considerations, contrast-enhanced brain MRI was performed as the first-line imaging modality.

MRI demonstrated a left temporal lobe mass with irregular gadolinium enhancement, central necrosis, and peritumoral edema. Flow voids within the tumor suggested prominent vascularity. In addition, ASL perfusion MRI was performed [Figure 1]. CBF maps demonstrated markedly elevated CBF within the tumor core and, importantly, high signal in the superior sagittal and both transverse sinuses consistent with early venous drainage. This illustrates the role of ASL as a noninvasive adjunct capable of detecting abnormal vascular shunting in hypervascular gliomas. Computed tomography angiography (CTA) revealed early venous filling with arterial feeders arising from branches of the left middle cerebral artery [Figure 2]. Following digital subtraction angiography (DSA) confirmed at least three independent diffuse tumor blushes and rapid arteriovenous shunting without a compact nidus, consistent with pseudo-AVM [Figure 3a and b].

Figure 1:

Preoperative brain magnetic resonance imaging. Axial T1-weighted (a) and T2-weighted (b) images obtained preoperatively demonstrate a heterogeneous mass in the left temporal lobe with surrounding vasogenic edema, producing a mass effect and showing an irregular ring enhancement pattern. Arterial spin labeling perfusion images (c and d) reveal marked hyperperfusion of the lesion with early venous drainage to the left lateral sinus and superior sagittal sinus through cortical (convexital) veins.

Figure 2:

Preoperative computed tomography angiography. Computed tomography angiogram (a) and 3D reconstructions (b and c) demonstrate an abnormal vascular network within the left temporal lobe. The left and middle images show a tangle of abnormal vessels with arterial feeders arising from an enlarged M2 segment of the middle cerebral artery and from branches of the middle meningeal artery. The right image reveals a saccular aneurysm of the anterior communicating–anterior cerebral artery complex (arrow).

Figure 3:

(a-b) Digital subtraction angiography demonstrates an abnormal vascular network in the projection of the tumor, with arterial feeders arising from branches of both the internal and external carotid arteries. (c) The right image, obtained after selective embolization, shows residual embolic material in the same region (arrow).

Given the high risk of intraoperative bleeding, endovascular embolization of the most prominent feeding arteries was performed before surgery. Partial embolization was achieved, reducing vascular supply from branches of the left external carotid artery [Figure 3c]. Craniotomy and microsurgical resection of the left temporal mass were performed 2 days after embolization. Gross total resection was obtained, although the intraoperative field remained hypervascular despite embolization. The procedure was tolerated without major complications. Figure 4 illustrates the early postoperative computed tomography and MRI scans following tumor resection.

Figure 4:

Postsurgical MRI and CT. (a) Axial T2-weighted MRI and (b) CT images demonstrate a large postoperative cavity without evidence of significant hemorrhage. The MRI shows cytotoxic edema within the left occipital lobe (arrow). On the corresponding CT image, residual embolic material is visible along the lateral margin of the postoperative cavity (arrow). MRI: Magnetic resonance imaging, CT: Computed tomography.

Histological examination revealed a diffusely infiltrating astrocytic tumor with marked nuclear atypia, brisk mitotic activity, microvascular proliferation, and extensive necrosis – features consistent with GBM. Immunohistochemistry was negative for IDH1 R132H mutation. Followed by polymerase chain reaction analysis, further confirmed the absence of IDH1/2 mutations, which confirmed the diagnosis of GBM. The Ki-67 proliferation index was 15%. These findings, together with the imaging and intraoperative evidence of hypervascularity, established the final diagnosis of GBM, with pseudo-AVM vascular features.

Postoperatively, the patient recovered without surgical complications. Neurological examination showed no new deficits. The patient remained at his presurgical neurological baseline, with persistent mild aphasia and homonymous hemianopsia. However, the right-sided limb weakness had improved. At the moment of case preparation, adjuvant radiotherapy followed by temozolomide chemotherapy was initiated according to the Stupp protocol. The patient is clinically stable.

DISCUSSION

Although pseudo-AVM GBM has been described in the literature, it remains an exceptional finding, reported mostly as isolated case studies.[4,5,9,18] Moreover, all existing reports emphasized the difficulty of distinguishing these entities radiologically.[1,4,5,9,13,16] The present case is distinguished by two important aspects. First, in addition to standard MRI, CTA, and DSA, we employed ASL perfusion MRI, which clearly demonstrated tumor hyperperfusion and early venous drainage, corroborating the angiographic findings in a noninvasive manner. To our knowledge, few reports have documented the use of ASL in confirming abnormal venous outflow in pseudo-AVM GBM,[15] and our case highlights its potential role as a complementary imaging tool. Second, the management strategy combined partial preoperative embolization of arterial feeders with subsequent resection of the tumor. Preoperative embolization in GBM remains uncommon and is rarely described in pseudo-AVM cases,[8] yet in our patient, it facilitated safer resection by reducing intraoperative bleeding risk.

The vascular mimicry observed in GBMs is best explained by their biology.[1] GBMs are highly angiogenic, driven by vascular endothelial growth factor and other factors, and they develop abnormal, tortuous vessels with thin walls and arteriovenous shunts.[6,7] In our case, this produced the full hemodynamic signature of AVM, with early venous drainage and high-flow circulation, but crucially without the discrete nidus that defines a true malformation. Interestingly, the cases of “mixed glioblastoma–AVM” have even been proposed,[11] but most authors agree that these are tumors with extreme vascular remodeling rather than genuine coexistence.[1,9,13]

Similar to previous reports,[1,4,9,13] our case demonstrated enlarged arterial feeders, early venous drainage, and diffuse tumor blush on angiography, mimicking a true AVM. These shared imaging characteristics support the concept that extreme tumor-driven angiogenesis can reproduce the hemodynamic appearance of high-flow vascular malformations.[17] However, most previously reported pseudo-AVM GBM cases relied on conventional MRI and DSA. In contrast, our case highlights the value of multimodal imaging. While DSA remains the gold standard for identifying arteriovenous shunting,[3] newer perfusion techniques such as ASL can contribute additional noninvasive information.[12,14,15] ASL has the advantage of being contrast-free and repeatable.[10,12] and in this case, it confirmed the presence of early venous drainage, paralleling the CTA and DSA findings. ASL has been described earlier as a promising method to identify tumor hyperperfusion and arteriovenous shunting detection.[10,12] Thus, incorporating this technique into the diagnostic workflow may reduce reliance on invasive angiography in selected patients or at least help raise suspicion for pseudo-AVM before DSA.

From a practical standpoint, pseudo-AVM GBMs can be differentiated from true AVM by careful attention to associated features: the presence of necrotic tumor core, mass effect, and surrounding edema on MRI,[19] the diffuse rather than compact blush on angiography,[13] and the very high relative CBF values as well as the early venous drainage features on ASL imaging.[14] This case, together with the published literature,[4,5,9,12,13] demonstrates that GBM with pseudo-AVM features, while rare, must be considered in the differential diagnosis of vascular-appearing intracranial lesions. Misclassification as AVM may lead to delay in oncologic therapy.[9] Recognition of the absence of a nidus, awareness of the tumor blush pattern, and correlation with MRI findings are essential to avoid diagnostic pitfalls.

A combined management strategy of partial preoperative embolization followed by subtotal resection enabled safe and effective tumor removal in this case. However, most published cases describe either biopsy or primary surgical resection.[1,4,9,13] Reports of preoperative embolization in GBM are scarce, and only isolated cases have been described.[8] Similar to the report by Imai et al.,[8] our experience indicates that targeted partial embolization can reduce arterial inflow and facilitate safer resection. It suggests that while embolization is not routinely employed in GBM, it may have a role in selected cases with extreme hypervascularity.

Taken together, comparison with existing literature suggests that pseudo-AVM GBM represents a severe angiogenic phenotype with extreme vascular remodeling and intratumoral shunting. Our case expands current knowledge by integrating advanced perfusion imaging and presurgical embolization into the diagnostic and therapeutic pathway. Prognosis remains poor, with survival largely dictated by tumor biology rather than vascular appearance, but awareness of this mimic is essential to avoid misdiagnosis and inappropriate treatment.

Data availability

Data can be provided by the corresponding authors upon request.

CONCLUSION

This case illustrates that GBM may present with AVM-like features, posing a diagnostic and therapeutic challenge. ASL perfusion MRI demonstrated noninvasive evidence of early venous drainage, consistent with angiographic findings, and may serve as a screening tool for this disease phenotype. Presurgical embolization followed by resection enabled safe tumor removal despite marked hypervascularity. Recognition of this rare presentation and correlation of multimodal imaging are critical for accurate diagnosis.

Ethical approval:

Institutional Review Board approval is not required.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of Artificial Intelligence (AI)-Assisted Technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

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