Continuous ictal discharges with high frequency oscillations confined to the non-sclerotic hippocampus in an epileptic patient with radiation-induced cavernoma in the lateral temporal lobe

Radiation-Induced Cerebral Cavernous Malformations: A Single-Center Experience and Systematic Literature Review

OBJECTIVE

Radiation was first demonstrated to be associated with cavernomagenesis in 1992. Since then, a growing body of literature has shown the unique course and presentation of radiation-induced cavernous malformations (RICMs). This study summarizes the literature on RICMs and presents a single-center experience.

METHODS

A prospectively maintained single institution vascular malformation database was searched for all cases of intracranial cavernous malformation (January 1, 1997-December 31, 2021). For patients with a diagnosis of RICM, information on demographic characteristics, surgical treatments, radiation, and surgical outcomes was obtained and analyzed. A comprehensive literature search was conducted using PubMed, Embase, Cochrane, and Web of Science databases for all reported cases of RICM.

RESULTS

A retrospective review of 1662 patients treated at a single institution yielded 10 patients with prior radiation treatment in the neck or head region and a subsequent diagnosis of intracranial RICM. The median (interquartile range) latency between radiation and presentation was 144 (108-192) months. Nine of 10 patients underwent surgery; symptoms improved for 5 patients, worsened for 3, and were stable for 1. The systematic literature review yielded 64 publications describing 248 patients with RICMs. Of the 248 literature review cases, 71 (28.6%) involved surgical resection. Of 39 patients with reported surgical outcomes, 32 (82%) experienced improvement.

CONCLUSIONS

RICMs have a unique course and epidemiology. RICMs should be considered when patients with a history of radiation present with neurologic impairment. When RICMs are identified, symptomatic patients can be treated effectively with surgical excision and close follow-up.

Natural history and treatment options of radiation-induced brain cavernomas: a systematic review

Radiation-induced cavernous malformations (RICMs) are delayed complications of brain irradiation during childhood. Its natural history is largely unknown and its incidence may be underestimated as RCIMS tend to develop several years following radiation. No clear consensus exists regarding the long-term follow-up or treatment. A systematic review of Embase, Cochrane Library, PubMed, Google Scholar, and Web of Science databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, was performed. Based on our inclusion/exclusion criteria, 12 articles were included, totaling 113 children with RICMs, 86 were treated conservatively, and 27 with microsurgery. We were unable to precisely define the incidence and natural history from this data. The mean age at radiation treatment was 7.3 years, with a slight male predominance (54%) and an average dose of 50.0 Gy. The mean time to detection of RICM was 9.2 years after radiation. RICM often developed at distance from the primary lesion, more specifically frontal (35%) and temporal lobe (34%). On average, 2.6 RICMs were discovered per child. Sixty-seven percent were asymptomatic. Twenty-one percent presented signs of hemorrhage. Clinical outcome was favorable in all children except in 2. Follow-up data were lacking in most of the studies. RICM is most often asymptomatic but probably an underestimated complication of cerebral irradiation in the pediatric population. Based on the radiological development of RICMs, many authors suggest a follow-up of at least 15 years. Studies suggest observation for asymptomatic lesions, while surgery is reserved for symptomatic growth, hemorrhage, or focal neurological deficits.

Nonconvulsive status epilepticus associated with Alzheimer's disease mimicking symptomatic focal epilepsy following the resection of a frontal parasagittal meningioma

Background

Epilepsies are frequent in patients with Alzheimer's disease (AD); however, epilepsies in AD can easily go unrecognized because they usually present as focal impaired awareness seizures or nonconvulsive status epilepticus (NCSE) and can overlap with other symptoms of AD.

Case Description

We performed an epilepsy surgery in a 69-year-old woman with progressive cognitive impairment and consciousness disorder, who was diagnosed with focal NCSE related to the resected meningioma in the right frontal parasagittal region. Intraoperative electrocorticography revealed localized periodic paroxysmal discharges with beta and gamma activities in the neighboring cortex where the meningioma existed. The histopathological diagnosis of AD was first made from the resected epileptogenic cortex.

Conclusion

Even when there is a suspected epileptogenic lesion that could cause focal NCSE, AD should be ruled out in elderly patients with progressive cognitive decline.