Ruptured distal AICA pseudoaneurysm presenting years after vestibular schwannoma resection and radiation

The prognosis and treatment effectiveness of de novo aneurysm formation after radiation therapy for brain tumor

Radiation therapy is a well-established, minimally invasive method of treating brain tumors. In recent years, the number of post-radiotherapy patients has increased, and delayed side effects are evident. De novo aneurysm formation after radiation often manifests as fatal subarachnoid hemorrhage (SAH), resulting in severe clinical outcomes. Nevertheless, the prognosis and therapeutic efficacy of radiation-induced aneurysms (RIAs) remain unclear. Using the PubMed database from 1980 to 2021, we screened 45 articles (53 individual cases) on RIAs; approximately 70% of RIAs were diagnosed after rupture. Of 38 ruptured RIAs, 12 (31.6%) had modified Rankin scale (mRS) 5-6. On the other hand, all unruptured RIAs (15 cases) recovered without neurological deficits (p = 0.012). Ten of the 39 ruptured RIAs were treated surgically, and 22 were treated endovascularly. There was no significant difference in mRS between treatment modalities (p = 0.393), but conservative therapy was significantly related to unfavorable outcomes (p = 0.025). To improve clinical outcomes, RIAs need to be diagnosed before rupture. Surgeons should be aware of de novo aneurysm formation in patients long after radiation therapy.

Outcomes of stereotactic radiosurgery in young adults with vestibular schwannomas

PURPOSE

Vestibular schwannomas (VSs) are comparatively rare in younger patients, and stereotactic radiosurgery (SRS) outcome data are limited. We aimed to evaluate long-term SRS outcomes concerning sporadic VSs in patients aged ≤ 40 years.

METHODS

Of 383 patients with VS who had undergone SRS at our institution between 1990 and 2017, we retrospectively compared younger and older patients' tumor control and radiation-induced complication rates using case-control propensity score (PS) matching.

RESULTS

The mean follow-up was 83 and 92 months in older and younger patients, respectively. Compared with older patients, younger patients were more likely to have a history of resection (20% vs. 39%, p = 0.006) and be treated with higher marginal doses (median, 12 Gy vs. 14 Gy; p = 0.014). Cumulative 5- and 10-year tumor control rates were higher in older patients (97.7% and 93.9%, respectively) than in younger patients (90.2% and 85.4%, respectively, p = 0.024). After PS matching, younger patients' cumulative tumor control rates (93.6%, 85.4%, and 85.4% at 5, 10, and 15 years, respectively) were similar to those of older patients (p = 0.411). No significant between-cohort differences in hearing preservation rates or other cranial nerve complications were observed. Two younger patients had malignant tumors several years post-SRS, with one patient having confirmed histological transformation.

CONCLUSIONS

SRS is equally effective for younger and older patients. Complications other than hearing deterioration are uncommon. However, malignant transformation is possible, and long-term post-SRS surveillance MRI is important. These data are useful for decision-making involving young adults with VSs.

Giant intracranial aneurysm following radiation therapy: literature review with a novel case discussion

BACKGROUND

The aim of this paper is to report the results of our review of the literature of published cases of intracranial aneurysms appearing after radiotherapy, and to present our case to add it to the current literature, in order to discuss the role of inflammation.

METHODS

We searched the PubMed database using combinations of the following MeSH terms: intracranial aneurysm, radiosurgery, radiotherapy, inflammatory changes in aneurysmal walls from 1967 to 2019.

RESULTS

51 studies, for a total cohort of 60 patients, are described. The median latency between the radiation treatment and the diagnosis was 9,83 years, ranging from a minimum of 0,33 to a maximum of 33. The modality of rays' administration was variable, and the dosage ranged from a minimum of 12 grays to a maximum of 177,2 grays. The anterior circulation appeared to be more frequently involved, and the most compromised vessel was the internal carotid artery. Radiation-induced vascular diseases have already been described in literature as well as RT-induced cellular and structural changes such as necrosis, macrophage or mononuclear cell infiltration, and several data support the role of inflammation in the development and remodelling of intracranial aneurysms, that, on one hand, favours them and, on the other, is necessary to their healing after endovascular treatment.

CONCLUSIONS

Our team suggested a new insight in the management of these vascular lesions, which corresponds to a lower threshold when deciding whether or not to treat, and a longer and stricter follow-up.

The Iatrogenic Development of an Anterior Cerebral Artery Pseudoaneurysm during Lamina Terminalis Fenestration-Genesis, Diagnosis and Therapy: Lessons Learned

Intracranial pseudoaneurysms (PSA) are scarcely presented in the literature. We describe the case of an intracranial PSA on the right anterior cerebral artery, which developed during the complicated surgical treatment of a ruptured right middle cerebral aneurysm. The pseudoaneurysm grew over time and was co-incidentally diagnosed 3 months after the original surgery. The PSA was successfully treated by coiling. In cases of vascular injuries during complicated brain surgery, the timely and careful radiological diagnosis of such a lesion is necessary to allow its fast and proper treatment and thus prevent the patient from potential risks.

Internal carotid artery aneurysms diagnosed after stereotactic radiosurgery for a growth hormone-secreting pituitary adenoma: a case report and literature review

Radiation therapy is associated with the subsequent development of cerebral aneurysms; however, stereotactic radiosurgery (SRS)-associated aneurysm cases have not been well documented, with only 18 cases reported to date. We present a case of intracranial aneurysms with the rupture occurring 20 years after SRS for a growth hormone-producing pituitary adenoma. This is the first report of aneurysms diagnosed following transsphenoidal surgery and SRS for pituitary adenoma. We believe that the aneurysm reported here is a consequence of the SRS treatment, and thus this may be a very rare long-term complication following radiation treatments.

Ruptured Pseudoaneurysm after Gamma Knife Surgery for Vestibular Schwannoma

Ruptured aneurysms of anterior inferior cerebellar artery (AICA) after radiotherapy for vestibular schwannoma (VS) are rare, and no definite treatment has been established for distal AICA pseudoaneurysms. We describe a 61-year-old man who underwent Gamma Knife surgery (GKS) for left VS. Follow-up magnetic resonance imaging (MRI) revealed partial regression of the tumor. Twelve years after GKS, he suffered from subarachnoid hemorrhage. Initial angiogram showed no vascular lesions; second left vertebral angiogram, 10 days after admission, demonstrated a pseudoaneurysm in the lateral pontine segment of the left AICA. The proximal portion of the AICA was occluded by a coil. Postoperative MRI revealed an infarction on the left side of the pons and brachium pontis. Although the patient suffered from mild postoperative cerebellar ataxia and facial and abducens nerve palsy, he was discharged 1 month postoperatively requiring no assistance with activities of daily living. Twelve months later, he recovered satisfactorily with a modified Rankin Scale grade of 1, and no recanalization of the aneurysm was found on MR angiography. Endovascular parent artery occlusion for ruptured aneurysms at distal AICA carries the risk of brain stem infarction, but should be considered when no other option is available such as after radiotherapy for VS.