Surgery for mesencephalic cavernoma: case report

Intrinsic midbrain tumor has been one of the most challenging therapeutic tasks in neurosurgery because of its prognosis and risks associated with surgical procedures. We encountered a rare case of cavernoma located in the anterior-mesencephalic region presented as parkinsonism tremor.

A 42-year-old woman had a resting tremor for 10 years. This tremor involved the left shoulder and the proximal and distal limb, which was exacerbated by any attempted movement and became grossly uncontrollable. She showed a partial right ophthalmoplegia with mydriasis. Her right upper and lower extremities had normal strength, but her left extremities had three-fifth strength. Her sensation was intact. Magnetic resonance imaging demonstrated a popcorn-like rounded lesion in the right ventral midbrain adjacent to the medial cerebral peduncle. To access this anterior-medial portion of the midbrain, we chose a frontotemporal transsylvian route via an orbitozygomatic craniotomy. With a longitudinal pial incision between the frontopontine fibers and the pyramidal tracts in the peduncle, the cavernoma was totally removed en bloc. After the operation, the tremor dramatically disappeared. The muscle strength of her left lower extremity improved to four fifths, whereas the upper extremity was still the same. The preoperative left oculomotor palsy seemed to have no improvement.

Clinically manifested cavernoma due to repeated hemorrhage needs surgical intervention. With an optimal surgical approach, fairly safe entry zones on the anterior face of the rostral brainstem may be accessible, which provides a successful resection of a mesencephalic cavernoma without postoperative complications.