Complete excision of a giant chondrosarcoma within the cavernous sinus: a case report and literature review.

Background: Primary skull base chondrosarcoma (SBC) is a rare malignant central nervous system tumor, often involving the cavernous sinus. Complete excision of tumors invading this region is exceptionally challenging due to the presence of the internal carotid artery and numerous nerves within the cavernous sinus, particularly in cases with substantial tumor volume.

Case presentation: This report describes a rare case of a massive primary SBC pushing the lateral wall of the cavernous sinus, measuring approximately 6.6 cm × 4.5 cm × 4.4 cm. Utilizing neurophysiological monitoring and intraoperative navigation, we successfully achieved complete tumor resection along the membranous structure via a left modified pterional approach (pterional-zygomatic arch-subdural-infratemporal approach), employing tools such as a cavitron ultrasonic surgical aspirator (CUSA) and piezosurgery. During the excision, localized rupture and bleeding of the internal carotid artery occurred, but prompt repair and anastomosis were performed. Postoperatively, the patient's symptoms markedly improved, and good reperfusion of the internal carotid artery was observed without new severe complications. The postoperative pathological diagnosis, according to the World Health Organization classification, was Grade 1 chondrosarcoma; therefore, radiotherapy was not administered. Magnetic resonance imaging at the 8-month follow-up showed no residual tumor or recurrence.

Conclusions: This case highlights that surgical complete excision of large intracavernous SBCs, while preserving vital neurovascular functions, is feasible and paramount for achieving favorable outcomes, particularly for Grade 1 and 2 SBCs, which comprise 82.4% of all subtypes. The use of a modified left pterional approach, intra-capsular tumor resection techniques, alongside CUSA and piezosurgery, provides valuable insights and serves as a reference for achieving complete excision of SBCs within the cavernous sinus.