Purely endoscopic transventricular approach for resection of a pineal region epidermoid cyst with third ventricle extension in a pediatric patient: a case-based review and literature analysis.

Background: Epidermoid cysts of the pineal region with posterior third ventricular extension are exceptionally rare, especially in the pediatric population. Despite their benign histology, their deep location near critical neurovascular structures poses considerable surgical challenges. We present the first reported pediatric case of a pineal epidermoid cyst extending into the posterior third ventricle successfully managed through a purely endoscopic transventricular approach, and analyze the literature.

Case Presentation: A 12-year-old boy presented with a three-week history of progressive headache, vomiting, and somnolence. Brain MRI revealed a well-defined, lobulated, non-enhancing lesion centered in the pineal region, extending into the posterior third ventricle, with marked diffusion restriction and no contrast enhancement-features consistent with an epidermoid cyst. Obstructive hydrocephalus was also noted. A pure endoscopic ventricular approach was performed, allowing complete tumor resection and simultaneous endoscopic third ventriculostomy (ETV) to treat the hydrocephalus. Histopathological analysis confirmed the diagnosis of an epidermoid cyst. Postoperatively, the patient developed a pyoventriculitis that required the placement of a ventriculoperitoneal shunt. No neurological deficits were observed. Follow-up with annual MRI over a six-year period showed no recurrence.

Conclusion: This case demonstrates the safety and efficacy of a purely endoscopic transventricular approach in selected pediatric patients with pineal region epidermoid cysts extending into the posterior third ventricle. This minimally invasive technique enables simultaneous management of both tumor and hydrocephalus, avoiding cortical transgression and reducing morbidity. It may represent a valuable alternative to traditional microsurgical approaches in appropriately selected cases.