Bektas, Delal

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

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.