Direct puncture Onyx embolization of a large calvarial metastasis with intracranial extension: Case report.

We report a case of renal cell carcinoma (RCC) metastasis to the calvarium and describe a strategy for percutaneous embolization of hypervascular calvarial tumors with intracranial extension. An elderly patient with history of RCC presented with left-sided weakness. Imaging studies showed a large right frontoparietal calvarial mass with intra- and extracranial extension. The tumor was devascularized by direct puncture tumor embolization using Onyx 18, allowing subsequent operative resection without significant blood loss or the need for flap reconstruction of the scalp. Compared to more common endovascular approaches, direct-needle puncture embolization of transcalvarial masses may offer lower risk of injury to scalp vessels and underlying brain parenchyma.