Parenchymal perianeurysmal cystic changes in the brain: report of five cases

Perianeurysmal cyst formation in the brainstem after coil embolization: illustrative case

BACKGROUND

Perianeurysmal cysts in the brainstem after endovascular coil embolization are rare, and their underlying mechanism remains unclear. The authors reported a case of a postcoiling perianeurysmal cyst that developed 6 years after endovascular coil embolization for a ruptured aneurysm and reviewed the related literature.

OBSERVATIONS

A 77-year-old woman had a history of subarachnoid hemorrhage 6 years earlier. The ruptured large left vertebral artery–posterior inferior cerebellar artery aneurysm was treated with endovascular coil embolization. Two years later, the aneurysm regrew and perianeurysmal brainstem edema was detected on magnetic resonance imaging (MRI); stent-assisted coil embolization combined with low-flow bypass was performed. Follow-up MRI showed that the perianeurysmal edema gradually transformed into a perianeurysmal cyst over the next 3 years. Finally, the perianeurysmal cyst caused gait disturbance with ataxia, and the patient received cyst puncture. After surgery, the symptom was immediately improved.

LESSONS

The authors reported, for the first time, postcoiling of perianeurysmal cyst formation treated by cyst puncture. If perianeurysmal edema is detected after endovascular coil embolization, especially for large aneurysms, it is necessary to consider progression to cyst formation and follow up over time. In addition, cyst puncture is effective, depending on the symptoms and the lesion.

Perianeurysmal parenchymal cysts – Case series and literature review

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Intracranial cysts are associated with a number of vascular lesions.

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They predominantly occur in larger, partially-thrombosed aneurysms and in older patients.

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There is a trend towards enlargement over time if untreated and a likelihood of recurrence following treatment.

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We hypothesise the cysts arise either from dilated Virchow-Robin spaces and/or inflammatory processes.

Giant tumefactive perivascular spaces in a pediatric patient: A rare radiological entity

Background:

Giant tumefactive perivascular spaces (TPVS) are radiological rarities and may mimic other neurological structural lesions. Fewer than 80 cases have been reported in the literature with even fewer in the pediatric population.

Case Description:

The authors present an image report showcasing a 3-year-old boy presenting with uncontrolled seizures despite multiple anti-epileptic medications. His magnetic resonance imaging showed multiple, non-contrast enhancing cyst clusters within the left parieto-occipital region that was hyperintense on T2-weighted imaging, and isointense to cerebrospinal fluid. Due to a characteristic absence of perilesional edema seen on fluid-attenuated inversion recovery imaging or diffusion restriction on diffusion-weighted imaging (DWI) sequences, this was diagnosed as a giant TPVS.

Conclusion:

Accurate diagnosis of these rare radiological entities is based on pathognomonic findings that can help prevent unnecessary surgery and guide management for patients, particularly in the pediatric population as seen in our case.

Large Parenchymal Perianeurysmal Cyst: A Case Report

Parenchymal perianeurysmal cysts are rare. We report a case of 50-year-old woman who presented with persistent headaches and episodes of vomiting for the last 2 months. Magnetic resonance imaging of the brain showed a well-defined solitary cystic lesion with a mural nodule measuring 5.4 × 5.2 × 4.6 cm in the right basifrontal region. The mural nodule was cortically based. It was hypointense on T2-weighted fluid-attenuated inversion recovery and showed intense contrast enhancement with few nonenhancing areas—no evidence of diffusion restriction. The cyst wall was nonenhancing, and magnetic resonance angiogram was unremarkable. Differential diagnoses included intra-axial gliomas such as ganglioglioma and pleomorphic xanthoastrocytoma. Right pterional craniotomy and a transcortical approach were made. Subtotal excision of cyst and clipping of right middle cerebral artery bifurcation thrombosed aneurysm were done. After 6 months of follow-up, patient is stable without any deficits. A parenchymal perianeurysmal cyst is a rare entity; it is crucial to be considered a differential diagnosis in any cystic lesion with the mural nodule.

Intracranial perianeurysmal cysts: case series and review of the literature

BACKGROUND

Intracranial perianeurysmal cysts are a rare finding associated with cerebral aneurysms. Patients may present with symptoms secondary to mass effect from perianeurysmal cysts requiring drainage. These lesions can masquerade as neoplasms if dedicated vascular imaging is not performed, leading to misdiagnosis.

METHOD

A retrospective search of our database was done for intracranial aneurysms that have been treated between 1998 and 2020. A literature search was then performed on PubMed and Google Scholar with the search terms 'aneurysm', 'intracranial/intracerebral', 'cyst', and 'perianeurysmal cyst'. Patient demographics, aneurysms and cysts characteristics were then summarized as a table and in the discussion.

RESULTS

Three cases where intracranial aneurysm had associated perianeurysmal cysts were found in our database. Combined with the available literature a total of 19 cases of perianeurysmal cysts have thus far been reported since this entity was first described in 2002. A significant number of perianeurysmal cysts (5/19) required intervention. In 5/19 cases the patient presented with a perianeurysmal cyst without a history of subarachnoid hemorrhage. Of the 10 cases where aneurysm follow-up was reported there were 5 cases where there was aneurysm recurrence necessitating re-treatment.

CONCLUSION

Significant variability exists in the patient demographics, aneurysm and cyst characteristics of perianeurysmal cysts. This suggests that there is no single unified etiology and pathogenesis. These lesions are a rare finding and at present do not appear to carry diagnostic or prognostic significance. Management of perianeurysmal cysts is case-dependent and intervention should be considered when treating the related aneurysm, especially in patients with secondary symptoms.

Cerebral Aneurysm Associated with an Arachnoid Cyst: 3 Case Reports and a Systematic Review of the Literature

BACKGROUND

Arachnoid cysts and intracranial aneurysms are not rare, but it is unusual for an aneurysm to be associated with an arachnoid cyst. The objective of this study was to reveal the association between arachnoid cysts and intracranial aneurysms.

METHODS

Methods included to report 3 cases with these 2 pathologies and to perform a systematic review of the English and Japanese literature using PubMed, Scopus, and Ichushi Web.

RESULTS

The first case was of a 46-year-old man with a subarachnoid hemorrhage on the basal cistern and bilateral arachnoid cysts in the middle fossa, the second was that of a 29-year-old woman with a subarachnoid hemorrhage at the basal cistern and an arachnoid cyst in the left middle fossa, and the third was that of a 60-year-old man with a right putaminal hemorrhage and contralateral unruptured aneurysm and arachnoid cyst. A literature search for similar cases found 27 patients.

CONCLUSIONS

It was difficult to diagnose a ruptured aneurysm in some cases with an arachnoid cyst because computed tomography scan showed atypical findings, such as no hemorrhage, intracystic localized hemorrhage, or subdural hematoma. This review revealed that aneurysms and arachnoid cysts were significantly located ipsilaterally and that they occurred together in relatively young patients.

Delayed Hydrocephalus and Perianeurysmal Cyst Formation After Stent-Assisted Coil Embolization of a Large, Unruptured Basilar Apex Aneurysm: A Case Report and Literature Review

PURPOSE

Endovascular aneurysm embolization possesses a unique set of infrequently seen complications distinct from those associated with microsurgical clipping, which may arise after an otherwise uncomplicated coil embolization procedure, including postembolization, hydrocephalus, and perianeurysmal cyst formation.

DESIGN

The authors report an illustrative case of 2 rarely seen complications of aneurysm embolization with literature review.

METHODS

We present a case of a basilar apex aneurysm that was treated with endovascular coil embolization with multiple Cerecyte (Micrus Endovascular, San Jose, Calif) coils and 2 Enterprise (Codman & Shurtleff, Inc, Raynham, Mass) stents.

RESULTS

Postembolization angiography demonstrated complete aneurysm obliteration without distal branch occlusion or other complication. Twenty-two months after the embolization, however, the patient presented with progressively worsening headaches. Repeat magnetic resonance imaging revealed hydrocephalus and a perianeurysmal cyst measuring 1 × 2 cm adjacent to the previously coiled basilar apex aneurysm. After endoscopic third ventriculostomy, the patient experienced significant relief of her headaches and was discharged to rehabilitation.

CONCLUSIONS

Clinicians should be aware that worsening or new neuro-ophthalmic findings may be the presenting sign of postembolization hydrocephalus or perianeurysmal cyst formation.

Intracranial Perianeurysmal Cyst: Still a Dilemma

Intracranial perianeurysmal cysts constitute an extremely rare entity with very few cases reported in the literature. These cysts present an unknown mechanism of formation and clinical significance. Several theories based on isolated cases have been proposed, without drawing a clear conclusion. It is also unknown if follow-up with imaging techniques is required or which is the most appropriate treatment. We describe an atypical case handled with a satisfactory outcome after endovascular treatment, suggesting the importance of hydrodynamic forces as the key factors in the mechanism of formation. We believe that this case can help in future analysis of this rare entity.

A FORM OF DYSPLASIA OR A FORTUITOUS ASSOCIATION? A CEREBRAL ANEURYSM INSIDE AN ARACHNOID CYST

OBJECTIVE

Although arachnoid cysts and intracranial aneurysms are very common lesions, their association in the same patient is rare. We present a case of a middle cerebral artery aneurysm ruptured into an arachnoid cyst. We found only six cases with intracystic hemorrhage reported in the literature. The presence of an arachnoid cyst can mislead clinical presentation. The patient presented a paradoxically small temporal fossa and thickening of the temporal and sphenoid bone. The authors suggest that this uncommon association (arachnoid cyst, atypical cranial vault, and “mirror-like” cerebral aneurysm) could represent a form of dysplasia.

CLINICAL PRESENTATION

A 46-year-old patient presented with a 3-week history of slight headaches, which had worsened in the last 3 days before presentation. Computed tomographic scans showed a cystic lesion located in the middle cranial fossa and sylvian fissure with suspected aneurysm dilation inside. Magnetic resonance imaging scans showed an intracystic hemorrhage but not subarachnoid hemorrhage. Paradoxically, changes in the cranial vault around the cyst were noted. Digital subtraction angiography showed bilateral “mirror” middle cerebral artery aneurysms.

INTERVENTION

A large right pterional craniotomy was performed with full microsurgical removal of the arachnoid cyst walls and aneurysm clipping. The aneurysm was in the medial wall of the arachnoid cyst with its dome inside the cyst. The contralateral aneurysm was clipped 2 weeks later. The follow-up period was uneventful, and the patient returned to normal life.

CONCLUSION

Rupture of a cerebral aneurysm into an arachnoid cyst is rare. Clinical presentation may be unusual because the cyst can prevent subarachnoid hemorrhage. A middle fossa cranial arachnoid cyst in the presence of temporal bone depression, small middle fossa, and thickness of squamous temporal bone and the lesser wing of sphenoid is rare and suggests that congenital factors may play an important role in their development. The exceptional association between “mirror” aneurysms and arachnoid cyst with bone changes suggests a possible congenital form of dysplasia.

Association between an arachnoid cyst and intracranial aneurysms misdiagnosed as a cystic tumor with a mural nodule

✓The authors report on a 63-year-old man initially admitted to an outside hospital for altered mental status and respiratory distress. A head computed tomography scan disclosed a right frontal cystic mass, suspected to be a neoplasm. An open biopsy was performed at an outside institution, and on visualization of the cyst, an aneurysm was found incidentally. Postoperatively, an angiogram and magnetic resonance image confirmed the presence of a distal right M1 segment aneurysm. The patient was transferred to our institution where, in addition to the middle cerebral artery lesion, a right anterior choroidal artery aneurysm was found intraoperatively; the necks of both aneurysms were clipped successfully. A review of the literature revealed 14 additional cases of intracranial aneurysms associated with arachnoid cysts. Data in the present report highlight the importance of considering an intracystic aneurysm in the differential diagnosis when reviewing cases that involve a cystic mass with a mural nodule. The authors provide a comprehensive summary of documented cases of aneurysms associated with arachnoid cysts. In addition, they include a discussion of prevailing thoughts on the origin and evolution of arachnoid cysts.

Parenchymal Perianeurysmal Cyst in the Brain: Case Report

OBJECTIVE AND IMPORTANCE:

Parenchymal perianeurysmal cysts are rare, and only seven cases have been reported. We present a case report with a 30 month follow-up on this topic. The possible etiopathogenetic mechanisms of cyst formation are discussed.

CLINICAL PRESENTATION:

A 54-year-old man with a 5–month history of headache and a computed tomography scan showing a giant parenchymal cyst located in the right temporal lobe with a mural enhanced nodule was admitted to our neurosurgical department with the diagnosis of cystic brain tumor. Magnetic resonance imaging followed by digital subtraction angiography identified the enhancing nodule as a large right middle cerebral artery aneurysm.

INTERVENTION:

Surgical treatment was performed; the aneurysm was clipped and the cyst evacuated. Postoperative digital subtraction angiography confirmed the clipping of the aneurysm at the neck. Serial magnetic resonance imaging controls showed the permanent collapse of the cyst.

CONCLUSION:

Parenchymal perianeurysmal cysts are rare. In the presence of parenchymal cysts neighboring main vessels, the possibility of a perianeurysmal cyst should be considered. In regard to the etiopathogenetic mechanisms responsible for the cyst development, the action of multiple coexisting factors seems to be the most applicable.

Development of a pontine cyst after endovascular coil occlusion of a basilar artery trunk aneurysm: case report

OBJECTIVE AND IMPORTANCE

Cyst formation within the brain parenchyma after endovascular coil occlusion of an intracranial aneurysm is a previously undescribed occurrence. We describe a 70-year-old woman who presented with a symptomatic pontine cyst 1 year after uncomplicated stenting and Guglielmi detachable coil occlusion of an unruptured basilar artery trunk aneurysm.

CLINICAL PRESENTATION

A 70-year-old woman presented with an episode of transient dysequilibrium and gait difficulty. Magnetic resonance imaging and cerebral angiography demonstrated a 15-mm distal basilar artery trunk aneurysm. Endovascular stenting and coil occlusion of the aneurysm were performed without technical complications. One year after the initial treatment, the patient developed progressive dysarthria, dysphagia, diplopia, and left hemiparesis. A large pontomesencephalic cyst adjacent to the coiled basilar aneurysm was identified on magnetic resonance imaging scans.

INTERVENTION

A subtemporal craniotomy and decompression of the pontomesencephalic cyst were performed. The patient's symptoms of brainstem dysfunction improved temporarily but recurred within 2 months, necessitating reoperation for cyst drainage and placement of a cyst-peritoneal shunt.

CONCLUSION

Intra-axial cyst formation after stenting and endovascular occlusion of an intracranial aneurysm is an unusual occurrence and should be considered in the differential diagnosis of new neurological deficits after endovascular treatment. The pathophysiological mechanism of cyst formation in this case is not known.