[Stepwise improvement of visual field after preoperative embolization and tumor resection of cerebral metastasis of alveolar soft part sarcoma].

We report a patient with a brain metastasis from an alveolar soft part sarcoma (ASPS) of the thigh whose visual field defect was resolved in a stepwise manner after preoperative embolization and tumor resection. A 29-year-old man who had undergone surgery to remove an ASPS situated in the thigh developed headaches and homonymous hemianopsia. His visual field defect was evaluated using a Goldmann perimeter. He was found to have a large, well-circumscribed mass in the right occipital lobe. This mass was visible on brain computed tomography and magnetic resonance imaging and was strongly and homogeneously enhanced following contrast administration. Selective angiography revealed a hypervascular mass supplied by branches of the right middle cerebral artery, and preoperative particulate embolization was performed to reduce intraoperative bleeding. A tumor-supplying branch of the middle cerebral artery was superselectively catheterized. For embolization, polyvinyl alcohol (PVA) particles of 90-180 μm in diameter were used. The visual field defect partially improved soon after the preoperative embolization. Surgical resection was performed 3 days after embolization, and the tumor was completely excised by a right occipital craniotomy. Preoperative embolization made the surgical resection easier. Intraoperative bleeding was easily controlled. The pathological diagnosis was ASPS. The intratumoral-embolized vessels were filled with PVA particles. After resection, the patient progressed well with further improvement in visual field function. Rapid improvement of the visual field can be used as an indicator of successful embolization without complications. (Received: July 16, 2013, Accepted: September 5, 2013).