Background: Cavernomas of the third ventricle are rare entities that provide significant therapeutic challenges. Because of the better view of the surgical field and the possibility to achieve a gross total resection (GTR), microsurgical approaches are more commonly used to target the third ventricle. Endoscopic transventricular approaches (ETVA), on the other hand, are minimally invasive procedures that can afford a straight corridor trough the lesion, avoiding bigger craniotomies. Moreover, these approaches have shown lower infectious risks and shorter hospitalization times. Case Description: A 58-year-old female patient accessed the Emergency Department complaining of headache, vomiting, mental confusion, and syncopal episodes for the past 3 days. An urgent brain computed tomography scan revealed a hemorrhagic lesion of the third ventricle, conditioning triventricular hydrocephalus, so an external ventricular drainage (EVD) was placed in an emergency setting. An magnetic resonance imaging (MRI) showed a 10 mm diameter hemorrhagic cavernous malformation originating from the superior tectal plate. An ETVA was performed for the cavernoma resection, followed by an endoscopic third ventriculostomy. After proving shunt independence, the EVD was removed. No clinical nor radiological complications were assisted in the postoperative period, so the patient was discharged 7 days after. The histopathological examination was consistent with cavernous malformation. An immediate postoperative MRI showed GTR of the cavernoma with a little clot around the surgical cavity, which appeared completely reabsorbed 4 months later. Conclusion: ETVA provides a straight corridor to the third ventricle, excellent visualization of the relevant anatomical structures, safe resection of the lesion, and treatment of the concomitant hydrocephalus by ETV.