Occult Rupture-Related Pseudoaneurysm Associated with a Ruptured Middle Cerebral Artery Aneurysm Diagnosed During Microsurgical Clipping

Pseudoaneurisma Oculto Associado a Aneurisma Roto de Artéria Cerebral Média Diagnosticado Durante Clipagem Microcirúrgica

• Jose Luis Quelho Filho    
• Paulo Eduardo Albuquerque Zito Raffa    
• Leonardo Vieira Nunes    
• Gabriel Ribas Nascimento de Melo    
• Rodrigo Shibaki    
• Lucas Crociati Meguins    

• https://doi.org/10.22290/jbnc.2026.14081145
• J Bras Neurocirur 37 (4):565-573, 2026

Resumo

Introdução: A formação de pseudoaneurisma relacionado à ruptura de aneurisma intracraniano verdadeiro é um fenômeno vascular excepcionalmente raro. Essas lesões são caracterizadas pela ausência de uma parede arterial verdadeira, sendo compostas por hematoma organizado e tecido fibroso em comunicação com o vaso parental. Os achados radiológicos são frequentemente inespecíficos, tornando o diagnóstico desafiador. Descrição do Caso: Um homem de 54 anos apresentou hemorragia subaracnoidea após crises convulsivas tônico-clônicas generalizadas associadas ao uso de cocaína. A angiotomografia computadorizada demonstrou um aneurisma bilobulado roto, originado na bifurcação da artéria cerebral média esquerda. Foi realizada clipagem microcirúrgica via pterional. No intraoperatório, identificou-se um pseudoaneurisma, previamente não reconhecido. Obteve-se a reconstrução completa com clipagem tanto do aneurisma verdadeiro quanto da cavidade pseudoaneurismática. Apesar de uma evolução pósoperatória longa e complexa, o paciente obteve recuperação neurológica completa. Conclusão: Os pseudoaneurismas relacionados à ruptura podem permanecer completamente ocultos aos exames de imagem vascular pré-operatórios, tornando-se evidentes apenas durante a exploração microcirúrgica. Neurocirurgiões devem manter um alto índice de suspeição ao tratar aneurismas rotos irregulares ou multilobulados, uma vez que o reconhecimento do componente pseudoaneurismático pode alterar significativamente o planejamento cirúrgico, facilitar a exclusão completa da lesão e reduzir o risco de ruptura intraoperatória e ressangramento pós-operatório.

Palavras-chave

Pseudoaneurisma relacionado à ruptura; Pseudoaneurisma intracraniano; Aneurisma de artéria cerebral média; Hemorragia subaracnoidea aneurismática; Clipagem microcirúrgica

Abstract

Introduction: Rupture-related pseudoaneurysm formation secondary to true intracranial aneurysm rupture is an exceptionally rare vascular phenomenon. These lesions are characterized by the absence of a true arterial wall and are composed of organized hematoma and fibrous tissue communicating with the parent vessel lumen. Radiological findings are frequently nonspecific or absent with diagnosis being challenging. Case Presentation: A 54-year-old man presented with poor-grade aneurysmal subarachnoid hemorrhage following generalized tonic-clonic seizures associated with cocaine use. Computed tomography angiography demonstrated a ruptured bilobulated aneurysm arising from the left middle cerebral artery bifurcation. Emergency microsurgical clipping was performed through a standard pterional approach. Intraoperatively, a previously unrecognized rupture-related pseudoaneurysm adjacent to the aneurysm dome and presumed rupture site was identified. Complete clip reconstruction of both the true aneurysm and pseudoaneurysmal cavity was achieved. Despite a long and complex postoperative course, the patient achieved complete neurological recovery. Conclusion: Rupture-related pseudoaneurysms may remain entirely occult on preoperative vascular imaging and become evident only during microsurgical exploration. Neurosurgeons should maintain a high index of suspicion when treating irregular or multilobulated ruptured aneurysms, as recognition of the pseudoaneurysmal component may significantly alter surgical planning, facilitate complete lesion exclusion, and reduce the risk of intraoperative rupture and postoperative rebleeding.

Keywords

Rupture-related pseudoaneurysm; Intracranial pseudoaneurysm; Middle cerebral artery aneurysm; Aneurysmal subarachnoid hemorrhage; Microsurgical clipping

References

1. Zheng Y, Lu Z, Shen J, Xu F. Intracranial pseudoaneurysms: evaluation and management. Front Neurol. 2020;11:582. https://doi. org/10.3389/fneur.2020.00582. PMid:32733358.

2. Crusius CU, Aguiar PH, Crusius MU. Mixed aneurysm: a new proposed nomenclature for a rare condition. Surg Neurol Int. 2017;8:29. PMid:28303209.

3. Mori K, Yamamoto T, Nakao Y, Esaki T. Ghost aneurysm associated with rupture of a cerebral aneurysm. Neurosurg Rev. 2004;27(3):208-12.

4. Nomura M, Mori K, Kawamura H. Pseudoaneurysm formation in a thrombus located at the rupture site of an irregularly shaped aneurysm. J Neurosurg. 2000;93(6):998-1000. https://doi.org/10.3171/ jns.2000.93.6.0998. PMid:11117874.

5. Nomura M, Mori K, Tamase A, et al. Pseudoaneurysm formation due to rupture of intracranial aneurysms: case series and literature review. Neuroradiol J. 2017;30(2):129-37. https://doi.

org/10.1177/1971400916684667. PMid:28059632.

6. Nomura M, Tamase A, Kamide T, Mori K, Seki S, Yanagimoto K. Pseudoaneurysm formation in intracerebral hematoma due to ruptured middle cerebral artery aneurysm. Surg J (NY). 2015;1(1):e47-9. https://doi.org/10.1055/s-0035-1567877. PMid:28824972.

7. Tsukiyama A, Yoshimoto Y, Watanabe M, Kuga Y, Takahashi H, Nakazato Y. Morphological change of cerebral aneurysm with possible pseudoaneurysm formation after rupture: case report and literature review. Neurol Med Chir (Tokyo). 2020;60(6):314-9.

8. Rodríguez-Hernández A, Sughrue ME, Akhavan S, HabdankKolaczkowski J, Lawton MT. Current management of middle cerebral artery aneurysms: surgical results and literature review. World Neurosurg. 

2013;79(1):143-50. PMid:23022651.

aneurysms in the United States. Neurosurgery. 2016;79(3):354-64. PMid:26901145.

11. Connolly ES Jr, Rabinstein AA, Carhuapoma JR, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage. Stroke. 2012;43(6):1711-37. https://doi.org/10.1161/STR.0b013e3182587839. PMid:22556195.

12. Hoh BL, Ko NU, Amin-Hanjani S, et al. 2023 guideline for the management of patients with aneurysmal subarachnoid hemorrhage: a guideline from the American Heart Association/American Stroke Association. Stroke. 2023;54(7):e314-70. https://doi.org/10.1161/ STR.0000000000000436. PMid:37212182.

13. Lawton MT, Vates GE. Subarachnoid hemorrhage. N Engl J Med. 2017;377(3):257-66. https://doi.org/10.1056/NEJMcp1605827. PMid:28723321.

14. Macdonald RL, Schweizer TA. Spontaneous subarachnoid 

haemorrhage. Lancet. 2017;389(10069):655-66. https://doi.org/10.1016/ S0140-6736(16)30668-7. PMid:27637674.

15. Molyneux AJ, Kerr RSC, Yu LM, et al. International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised comparison of effects on survival, dependency, seizures, rebleeding, subgroups, and aneurysm occlusion. Lancet. 2005;366(9488):809-17. https://doi.org/10.1016/S0140-6736(05)67214-5. PMid:16139655.

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1Department of Neurosurgery, Faculdade de Medicina de São José do Rio Preto – FAMERP, São José do Rio Preto, SP, Brasil.

2Faculdade de Medicina de São José do Rio Preto – FAMERP, São José do Rio Preto, SP, Brasil

3Fundação Faculdade Regional de Medicina de São José do Rio Preto – FUNFARME, Hospital de Base, São José do Rio Preto, SP, Brasil.

 

Received Jul 18, 2026 

Corrected Aug 4, 2026 

Accepted Aug 8, 2026