Resection of a thalamomesencephalic cavernous malformation via a retrosigmoid supracerebellar transtentorial approach: illustrative case.

BACKGROUND

Thalamomesencephalic cavernous malformations are deep lesions located near sensory, motor, and visual pathways as well as the deep venous system, making surgical treatment challenging. Careful corridor selection is essential to minimize injury to eloquent structures.

OBSERVATIONS: A 35-year-old man presented with progressive left facial and hemibody numbness and low-frequency tinnitus. MRI showed a right thalamomesencephalic lesion adjacent to the posterior third ventricle but separated from the ventricular system by functional parenchyma. Tractography demonstrated anterior displacement of the corticospinal tract and lateral displacement of the optic radiations. The lesion was resected through a right retrosigmoid supracerebellar transtentorial approach in the left lateral decubitus position. Gross-total resection was achieved. Postoperative MRI at 7 days, 3 months, and 1 year showed no residual or recurrent lesion. One-year tractography demonstrated preservation of the corticospinal tract and optic radiations.

LESSONS: A tailored retrosigmoid supracerebellar transtentorial corridor may enable safe resection of selected thalamomesencephalic cavernous malformations while preserving eloquent tracts and deep neurovascular structures. https://thejns.org/doi/10.3171/CASE26210.