Central Nervous System Solitary Fibrous Tumor: En Bloc Resection with Transverse Sinus Sacrifice Through a Combined Occipital and Infratentorial Approach: Surgical Video.

Introduction: Central nervous system solitary fibrous tumors (CNS-SFTs), previously classified as hemangiopericytomas, are rare and highly vascular mesenchymal neoplasms characterized by an aggressive biological behavior, high recurrence rates, and propensity for venous sinus invasion. Gross-total en bloc resection remains the cornerstone of treatment whenever technically feasible. We present the microsurgical management of a recurrent CNS solitary fibrous tumor invading the transverse sinus. Case Report: A 30-year-old man previously underwent microsurgical resection of a central nervous system solitary fibrous tumor two years earlier. He presented with recurrent headaches associated with visual photopsias. Magnetic resonance imaging demonstrated tumor recurrence centered at the left occipital region with extensive invasion of the left transverse sinus. Preoperative digital subtraction angiography confirmed complete occlusion of the left transverse sinus, allowing safe planning for sinus sacrifice during tumor resection. Microsurgical treatment was performed through a combined left occipital supratentorial and infratentorial craniotomy. To maximize exposure of the transverse-sigmoid junction, a retrosigmoid mastoidectomy was performed, permitting complete skeletonization of the transverse and sigmoid sinuses and facilitating vascular control. Following extradural exposure, the proximal transverse sinus was ligated near the torcular Herophili under direct microscopic visualization after confirming intraluminal tumor extension. Distal ligation was subsequently completed, and the tumor was removed en bloc together with the invaded segment of the transverse sinus, achieving gross-total resection while preserving the surrounding neurovascular structures. Results: The immediate postoperative neurological examination demonstrated no new neurological deficits. During the postoperative period, the patient developed communicating hydrocephalus, cerebrospinal fluid leakage, and bacterial meningitis. These complications were successfully managed with direct surgical repair of the cerebrospinal fluid fistula, implantation of a programmable ventriculoperitoneal shunt, and targeted intravenous antibiotic therapy. The patient recovered without permanent neurological sequelae. Postoperative magnetic resonance imaging confirmed gross-total tumor resection, and follow-up imaging demonstrated no evidence of residual disease. Conclusion: Complete microsurgical resection remains the treatment of choice for recurrent CNS solitary fibrous tumors involving the dural venous sinuses. When preoperative angiography confirms complete venous sinus occlusion, en bloc resection of the involved transverse sinus can be safely performed. A combined occipital supratentorial-infratentorial approach with adjunctive mastoidectomy provides excellent exposure of the transverse-sigmoid junction, facilitating vascular control and radical tumor removal while minimizing neurological morbidity.