Endoscopic Endonasal Approach to Mesencephalic Cavernous Malformations

Background: Symptomatic cavernous malformations involving the brainstem are difficult to access by conventional approaches, which often require dramatic brain retraction to gain adequate operative corridor. Here, we present a successful endoscopic endonasal transclival approach for resection of a hemorrhagic, symptomatic mesencephalic cavernous malformation.

Case description: A 20-year-old woman presented with acute onset of headache, nausea, and vomiting. Computed tomography scan revealed a ventral midbrain hemorrhage. On day 3 of admission, the patient developed left-sided hemiparesis, restriction of medial and lateral left-eye movements, and loss of left pupillary light reflex. Subsequent magnetic resonance imaging demonstrated an increase of the midbrain lesion to 1.2 cm × 1.7 cm. Diffusion tensor imaging showed compression and lateral displacement of the right corticospinal tract near the thalamus and cerebral peduncle. Given the patient's clinical presentation and the findings on imaging, we suspected a mesencephalic cavernous malformation.

Conclusions: The patient underwent an endoscopic endonasal transclival resection of a ventral midline mesencephalon cavernous malformation. A dark red lesion was directly visualized under the endoscope. After a small cortiectomy, the pial and perforator vessels were dissected, and dark-brown blood was drained from the cavernoma cavity. Using a biopsy forceps and with careful attention to the cavernoma borders, the lesion was removed and hemostasis was achieved. Pathologic examination confirmed cavernous malformation. One week after the operation, magnetic resonance imaging demonstrated total resection of the lesion. A 3-month follow-up revealed improved neurologic symptoms with minimal surgical morbidity.