gms | German Medical Science

Objective: Chondrosarcomas of the skull are very rare tumors originating typically from the petrooccipital fissure. Complete surgical resection is the most effective treatment, since photon radiotherapy and chemotherapy are not effective in most subtypes. Depending on the exact tumor extension and consistency, median and lateral skull base approaches can be suitable for function preserving resection.

Method: Between 2008 and 2010 3 female patients (age 37, 60, 73 years) with chondrosarcomas of the skull base were treated. Two of these patients presented with double vision, one with hoarseness. Two patients underwent previous surgery, one via a lateral suboccipital approach, the other patient via an anterolateral high cervical approach. A pure endoscopic transnasal approach was used in 2 of these patients and an anterosigmoidal, infralabyrinthine approach in the other case. All surgeries were performed with neuronavigation (BrainLAB AG, Feldkirchen, Germany).

Results: Gross total resection was achieved in 2 and subtotal resection in another case. During the lateral approach, the posterior semicircular canal was opened, resulting in surditas and vertigo. No further new cranial nerve deficit was noted. In both cases via the endoscopic transnasal approach the resection was extended after postoperative images showed residual tumor accessible via the same approach. In one of these cases, a small tumor remnant was left medial to the inner auditory canal. One case was sent for proton beam (37 year old patient), one for heavy ion therapy beam 73 year old patient), in the third patient did not undergo any additional treatment. During follow-up, no tumor progression was found (range of progression free survival: 24–48 months).

Conclusions: Chondrosarcomas are paramedian tumors of the skull base. Nevertheless, the pure endoscopic transnasal approach seems feasible as an alternative to lateral approaches. Curettage of soft tumor in the petrous apex can be achieved, but drilling of tumor invaded bone is only possible dorsal but not lateral of the internal carotid artery.