Minimizing cortical disturbance to access ventricular subependymoma - A novel approach utilizing spinal minimally invasive tubular retractor system

Lateral ventricle subependymoma resected with a transcallosal approach: illustrative case

BACKGROUND

Subependymomas are World Health Organization grade I tumors, and 30% occur in the lateral ventricles. Surgery is the mainstay of treatment, and the transcallosal or transcortical/transsulcal approaches are preferred for those tumors occurring near the foramen of Monro or atrium. Visualization, proximity to the fornix and basal ganglia, hydrocephalus, and brain retraction during surgery make these operations challenging. The authors present the case of a 65-year-old male with a subependymoma located in the left lateral ventricle. The tumor was completely resected using an interhemispheric/transcallosal approach.

OBSERVATIONS

The authors analyze the anatomopathological features of subependymoma, along with the clinical behavior and therapeutic options. The authors discuss in detail the advantages and disadvantages of the interhemispheric/transcallosal approach for resection of these tumors.

LESSONS

Subependymomas are slow-growing lesions with an indolent yet complicated course making surgical removal challenging yet feasible using the correct techniques. The interhemispheric transcallosal approach offers an excellent route for the resection of large subependymomas, but there is still a significant risk for postoperative complications.

Tumor characteristics and surgical outcomes of intracranial subependymomas: a systematic review and meta-analysis

OBJECTIVE

The tumor characteristics and surgical outcomes of intracranial subependymomas are poorly defined. In this study the authors aimed to provide a comprehensive review of all clinical, pathological, radiological, and surgical aspects of this important neoplasm to inform future management strategies.

METHODS

A systematic review and meta-analysis of MEDLINE, EMBASE, Cochrane, and Google Scholar databases adherent to PRISMA guidelines was conducted.

RESULTS

Of the 1145 articles initially retrieved, 24 studies encompassing 890 cases were included. The authors identified 3 retrospective cohort studies and 21 case series, but no controlled trials. Mean age at presentation was 46.7 ± 18.1 years with a male predominance (70.2%). Common sites of tumor origin were the lateral ventricle (44.5%) and fourth ventricle (43.1%). Cumulative postoperative mortality and morbidity rates were 3.4% and 24.3% respectively. Meta-analysis revealed that male sex (HR 3.15, 95% CI 1.39-7.14, p = 0.006) was associated with poorer 5-year overall mortality rates. All-cause mortality rates were similar when performing subgroup meta-analyses for age (HR 0.50, 95% CI 0.03-7.36, p = 0.61), smaller subependymoma size (HR 1.51, 95% CI 0.78-2.92, p = 0.22), gross-total resection (HR 0.65, 95% CI 0.35-1.23, p = 0.18), and receipt of postoperative radiation therapy (HR 0.88, 95% CI 0.27-2.88, p = 0.84). Postoperative Karnofsky Performance Index scores improved by a mean difference of 1.62 ± 12.14 points (p = 0.42). The pooled overall 5-year survival rate was 89.2%, while the cumulative recurrence rate was 1.3% over a median follow-up ranging from 15.3 to 120.0 months. The pure subependymoma histopathological subtype was most prevalent (85.6%), followed by the mixed subependymoma-ependymoma tumor variant (13.7%).

CONCLUSIONS

Surgical extirpation without postoperative radiotherapy results in excellent postoperative survival and functional outcomes in the treatment of intracranial subependymomas. Aggressive tumor behavior should prompt histological reevaluation for a mixed subependymoma-ependymoma subtype. Further high-quality controlled trials are still required to investigate this rare tumor.