Primary Chondrosarcomas of the Skull Base: A Systematic Review

Introduction: Primary skull base chondrosarcomas (SBCs) are rare intracranial neoplasms that can show invasive growth patterns. Surgical resection is the current standard but poses several risks. Photon and proton-based radiotherapy represent additional feasible treatments.

Objective: To systematically review clinical characteristics and management strategies of patients with primary SBCs.

Methods: We searched PubMed, EMBASE, Scopus, Web-of-Science, and Cochrane upon the PRISMA statement. Studies reporting clinical outcomes data of patients with primary SBCs were included. Clinical characteristics, management strategies, and treatment outcomes were analyzed.

Results: We included 32 studies comprising 1,288 patients. Median age at diagnosis was 42.5 years (range, 18–85). Tumors mostly infiltrated the middle fossa (72.1%), involving the petrous bone (36.9%), the clivus (22%), and the petroclival synchondrosis (20.7%). Less frequently, SBCs infiltrated the anterior fossa (12.8%), involving the supra/parasellar region (7.1%) and/or the orbit (2.1%), and the posterior fossa, extending to the jugular foramen (3%) and/or the foramen magnum (1.3%). Tumors invaded the cavernous sinus in 41.6% patients and caused extra-axial compression of the brainstem and the optic apparatus in 50.7% and 39.6% cases. Median duration of symptoms was 16 months (range, 0.1–312), with diplopia (28.3%) and headache (22.1%) being the most common. Cranial neuropathies were reported in 791 patients (61.4%). The fifth (19.7%) and the sixth (30.8%) cranial nerves were most commonly involved, and 161 patients (20.3%) had multiple neuropathies. 29 patients (3.7%) presented with hypopituitarism. Median tumor volume was 24.3 cm³ (range, 1.6–88.4). At histopathology, conventional SBCs were the most common (86.6%), followed by myxoid (7.7%), mesenchymal (5.7%), and undifferentiated (0.4%) tumors. Surgical resection (93.2%) was preferred over biopsy (6.8%), with subtotal and gross-total resection obtained in 46.6% and 36.7% patients, respectively. The most frequent open surgical approaches were the frontotemporal orbitozygomatic (18.3%) and the pterional (12.4%) approaches. A total of 92 patients (7.7%) underwent endoscopic resection through an endonasal route, and 17 patients (1.4%) received combined endoscopic plus open surgical resection. Postoperative cerebrospinal fluid leaks occurred in 35 patients (2.7%). Transient post-surgical complications were described in 85 patients (7.1%), mostly new cranial neuropathies (64.7%) and meningitis (18.8%), while persistent complications were reported in 59 patients (4.9%), mostly new cranial neuropathies (62.7%) and intracerebral hemorrhages (13.6%). A total of 1014 patients (78.7%) received radiotherapy: photon-based in 417 (41.1%), proton-based in 654 (64.5%), and carbon-based in 133 (13.1%). 261 patients (25.7%) experienced post-radiotherapy complications, with hypopituitarism (48.3%), hearing loss (22.2%), and radionecrosis (11.5%) being the most common. At posttreatment follow-up, symptomatic improvement was described in 46.7% patients, and most radiotherapy-treated lesions showed radiological stable volumes (58.3%) or tumor shrinkage (27.1%). Median follow-up was 67 months (range, 0.1–376). SBCs recurrences were reported in 210 cases (16.3%), with 5-year and 10-year local control rates of 84.3% and 67.4%, respectively. Most patients were alive at last follow-up (88.8%), with 5-year and 10-year overall survival rates of 94% and 84%, respectively.

Conclusion: Primary SBCs can severely impair clinical status and quality-of-life. Both surgical resection and radiotherapy are effective treatments, with low rates of complications and favorable rates of local tumor control.

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Artikel online veröffentlicht:
15. Februar 2022