Citations

BACKGROUND Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration caused by disruption of the dentato-rubro-olivary pathway (Guillain-Mollaret triangle). It is most described following surgical intervention or acute hemorrhagic injury affecting that pathway. However, longitudinal imaging documenting the natural progression of HOD in patients with brainstem cerebral cavernous malformations (CCMs) remains sparsely described at the individual patient level. OBSERVATIONS The authors present the case of a 70-year-old woman with a pontine CCM followed longitudinally over 4 years. Initial imaging demonstrated a right-sided pontine lesion with unilateral HOD in the absence of symptoms. Over time, the CCM enlarged and extended across the midline, coinciding with the development of bilateral HOD and delayed onset of gait imbalance and palatal myoclonus. No surgical intervention was performed. LESSONS In this case, the radiographic evolution from unilateral to bilateral involvement occurred concurrently with the delayed clinical manifestation of HOD. https://thejns.org/doi/10.3171/CASE26577

OBJECTIVE The aim of this study was to elucidate the long-term morbidity associated with untreated cerebral cavernous malformation (CCM). METHODS From a prospectively maintained database of patients with CCM, we assessed functional outcome as measured using the modified Rankin Scale (mRS) score at baseline and the last untreated follow-up evaluation. Disability was defined as an mRS score ≥ 3. Kaplan-Meier curves were used to assess the time to disability, and Cox proportional hazards models were used to determine risk factors for disability. Furthermore, the predictive performance of a previously published nomogram for morbidity in CCM was assessed. RESULTS The cohort consisted of 332 patients (58.4% female, mean age at diagnosis 44.5 years), with 19.8% having the familial form and 28.0% having a CCM located in the brainstem. Of 48 patients who presented with symptomatic hemorrhage (SH) and who did not undergo surgery or have a prospective SH, 27.1% had an mRS score ≥ 3 at diagnosis. By 1 year and 5 years, this improved to 6.2% and 4.7%, respectively. Over a mean follow-up duration of 6.6 years, 103 of 332 patients (31.0%) had one prospective SH and 48 (14.5%) had multiple prospective SHs. Patients with brainstem-located CCM had an 18.8% 5-year and 35.4% 10-year risk of disability compared with 4.1% and 7.5%, respectively, in patients with a nonbrainstem location (p < 0.0001). Multivariate analysis showed that a brainstem location, history of self-reported psychiatric disorder, and ≥ 2 SHs were predictive of disability at the last follow-up. External validation of a published nomogram demonstrated high specificity but limited sensitivity for predicting disability, with an area under the receiver operating curve of 0.687 for mRS scores ≥ 2 and 0.783 for mRS scores ≥ 3. CONCLUSIONS Most patients improved after a first hemorrhage, with the most improvement occurring in year 1. Disability increased with each SH. Disability was associated with 2 or more SHs, a brainstem location, and a self-reported psychiatric diagnosis. Ten-year disability risk with a nonbrainstem CCM location was < 8%.

OBJECTIVE This study evaluated the utility of routine versus symptom-driven MRI to detect hemorrhage in patients with sporadic cerebral cavernous malformations (CCMs) and assessed associated radiographic changes at the first clinical follow-up. METHODS The authors analyzed a prospective, single-center cohort of patients with sporadic, brain-only CCMs who underwent at least 1 follow-up MRI after diagnosis. Clinical and radiological data were obtained from a longitudinal registry. Follow-up findings included lesion growth (≥ 3 mm), changes in Zabramski classification, persistent T1-weighted hyperintensity, edema, and hemorrhage. MRI indications were categorized as routine surveillance or symptom driven (e.g., new or worsening focal neurological deficit [FND], headache, or seizure). Univariate and multivariate analyses were performed to assess predictors of symptomatic hemmorhage (SH). RESULTS Of 236 included patients, 59.3% were female, and 39.8% initially presented with SH. At the first follow-up MRI, radiographic hemorrhage was observed in 13 of 68 patients (19.1%) imaged for new or worsening neurological symptoms (FND, headaches, or seizures), compared to 2 of 168 patients (1.2%) during routine or non–CCM-related surveillance. Among these 168 patients, 17 (10.1%) showed radiological progression—including lesion growth (n = 11 [6.5%]), a change to a more aggressive Zabramski type (n = 10 [6.0%]), and radiological evidence of acute hemorrhage (n = 2 [1.2%]). Most of these events (88.2%) occurred within 2 years. SH was characterized by lesion growth, moderate-to-severe T1-hyperintensity, and edema. Baseline lesion size and location did not predict hemorrhage. New or worsening FND predicted hemorrhage, whereas seizure and headache alone did not. In the multivariate analysis, only the presence of new or worsening FND remained independently associated with hemorrhage (OR 13.73, p < 0.001). CONCLUSIONS In patients with known CCM, MRI should be performed in case of new or worsening FND, as this was the strongest predictor of hemorrhage. Routine surveillance had limited diagnostic yield in asymptomatic patients but may be appropriate in select cases.

OBJECTIVE Brain arteriovenous malformations (bAVMs) are rare but potentially devastating cerebrovascular lesions. Activating KRAS mutations are common in sporadic bAVMs, but their clinical implications remain unclear. The aim of this study was to investigate a novel therapeutic strategy for hemorrhagic bAVMs based on dual inhibition of the mitogen-activated protein kinase (MAPK) and vascular endothelial growth factor (VEGF) pathways using an engineered mouse model with a titratable KRAS G12V - GFP transgene. METHODS The AAV-BR1-CAG vector was used to deliver a KRAS G12V - GFP transgene specifically to cerebral endothelial cells. Mice received 5 × 10 7 to 5 × 10 10 genome copies of the vector, and bAVM formation, intracerebral hemorrhage (ICH), and overall survival were assessed. Mice with established hemorrhagic bAVMs were subsequently treated with trametinib (MEK inhibitor) or RMC-7977 (RAS inhibitor), with or without an anti–mouse VEGF antibody, starting 4 weeks after viral delivery. Overall survival was assessed. RESULTS Selective overexpression of KRAS G12V - GFP in cerebral endothelial cells led to the formation of bAVMs in a dose-dependent manner. Mice that received the highest transgene dose developed significantly more bAVMs, exhibited a higher ICH burden, and had worse overall survival compared with those that received lower transgene doses. In mice receiving the highest transgene dose, trametinib alone modestly improved the median overall survival (8.4 weeks vs 6.4 weeks, p = 0.049), while single-agent RMC-7977 showed no significant benefit. Anti-VEGF therapy alone reduced survival (6.9 weeks vs 9.6 weeks, p = 0.044). However, combination therapy with trametinib or RMC-7977 and anti-VEGF antibody significantly prolonged survival, with the most pronounced benefit seen in the RMC-7977 plus anti-VEGF group (13.1 weeks vs 6.7 weeks in controls, p = 0.024). CONCLUSIONS Our findings suggest that, in addition to promoting bAVM formation, KRAS mutations in cerebral endothelial cells might be causally implicated in bAVM rupture. Additionally, concomitant inhibition of the MAPK and VEGF pathways could be a promising novel therapeutic strategy for KRAS -mutated bAVMs.

BACKGROUND AND OBJECTIVES: This study aimed to evaluate predictors of hypertrophic olivary degeneration (HOD) in patients with brainstem cerebral cavernous malformations (CCMs) and to examine its association with functional outcomes. METHODS: A cohort of 120 patients with brainstem CCM was analyzed using prospectively collected registry data and retrospective chart reviews. Demographic, clinical, radiological, and surgical data were evaluated. Predictors of HOD and poor functional outcomes were identified through univariate and multivariate analyses. RESULTS: The cohort included 54 females (45.0%), with a mean age at diagnosis of 43.8 years (SD = 16.5). Symptomatic hemorrhage was present in 70.8% of patients at diagnosis, and 28.3% underwent surgical intervention. Radiographic HOD was observed in 20% of patients (n = 24), with 87% of cases involving lesions within the Guillain–Mollaret triangle (GMT). Larger lesion size (odds ratio [OR] = 1.09, 95% CI: 1.01-1.19, P = .027), pontine location (OR = 19.81, P = .006), and GMT involvement (OR = 25.24, P < .001) were significantly associated with HOD. Repeated symptomatic hemorrhage and surgery, including the extent of resection, did not predict the development of HOD. Patients with HOD had worse functional outcomes at last follow-up ( P = .012), with GMT involvement remaining the sole independent predictor of mRS ≥3 (OR = 3.44, P = .040). CONCLUSION: HOD reflects trans-synaptic degeneration within the GMT and is strongly associated with lesion location and size. It serves as a radiological marker of cumulative damage to the brainstem. Preoperative imaging and risk stratification focusing on GMT involvement are critical for guiding management and counseling patients with brainstem CCM.

BACKGROUND AND OBJECTIVES: This study aimed to investigate the clinical presentation, natural history, and long-term outcome of sporadic cerebral cavernous malformations (CCMs) based on initial Zabramski classification. METHODS: A prospective cohort of 285 patients with sporadic CCMs was analyzed. Patients were classified into Zabramski Types I-IV based on diagnostic MRI. Clinical presentation, lesion size, location, and developmental venous anomaly presence were recorded. Prospective symptomatic hemorrhage (SH) (censored at first hemorrhage, surgery, or last follow-up) and functional outcomes were assessed using Kaplan-Meier and Cox regression analyses. Functional outcomes were measured with the modified Rankin Scale (mRS) at baseline, annually, and at the last follow-up. RESULTS: The cohort included 58.9% women and 41.1% men, with a mean age at diagnosis of 44.5 years. Zabramski Types I-IV (n = 113, 125, 40, and 7, respectively) differed significantly in clinical presentation ( P < .001). Type I lesions were symptomatic in 97.3%, Types II and III in 34.4% and 22.5%, respectively, while all Type IV lesions were asymptomatic. Type I lesions had the highest annual hemorrhage rate (13.9% per year) and a 5-year cumulative risk of 50.6%. Types II and III had lower rates (2.9% and 1.8%), whereas no hemorrhages occurred in Type IV lesions. At baseline, 70.8% of Type I patients had mRS ≥2, which decreased to 35.4% at the last follow-up. Type III lesions had favorable outcomes, with 7.5% of patients having mRS ≥2 at the last follow-up. Type IV lesions remained asymptomatic throughout. Severe SH significantly increased the odds of poor outcomes (mRS ≥3; P < .001), whereas Zabramski type was not predictive of outcomes after adjustment. CONCLUSION: Zabramski classification aids in stratifying hemorrhage risk and guiding management in CCMs. Severe SH is a critical determinant of functional outcomes, underscoring the need for comprehensive risk assessments and individualized patient care strategies.