Giant cell tumors of the skull base: case series and current concepts.

OBJECTIVE To study the clinical features, tumor characteristics and outcomes of giant cell tumors (GCTs) in the skull base based on long-term follow-up. We also report the largest series of GCTs in the temporal bone and the lateral skull base. MATERIALS AND METHODS A retrospective study was conducted of all GCTs managed at the Gruppo Otologico, a quaternary referral skull base institute, in Italy from 1993 to 2013. The clinical features, investigations, surgical management and follow-up were recorded. The surgical approaches used were infratemporal fossa approach (ITFA) type B and D and middle cranial fossa (MCF) approaches. RESULTS AND OBSERVATIONS A total of 7 patients with GCTs of the skull base were treated at our institution. The principal complaints were hearing loss reported in 6 (85.71%) patients, tinnitus in 5 (71.43%) and swelling in 3 (42.9%). Pure-tone audiometry showed conductive hearing loss in 5 (71.43%) patients. High-resolution CT scan and MRI with gadolinium enhancement were done in all patients. Radiology showed involvement of the ITF and middle ear in 6 (85.71%) patients each, temporomandibular joint in 4 (57.14%) patients, invasions of the squamous part of the temporal bone, mastoid, MCF and greater wing of sphenoid in 3 (42.9%) patients each and the petrous bone in 2 (28.6%) patients. ITFA type B was applied as an approach for tumor removal in 5 (71.43%) patients, including a case where an additional MCF approach was employed, and ITFA type D and the transmastoid approach were applied in 1 (14.3%) patient each. Total tumor removal and successful cure was achieved in 6 (85.71%) patients. Subtotal removal leading to recurrence and eventual mortality was the result in 1 (14.3%) patient. CONCLUSIONS A thorough knowledge of the anatomy of the skull base and the various skull base approaches is necessary to tackle GCTs. ITFA type B and D combined with MCF approaches provide good exposure of the tumor with minimal postoperative sequelae and good locoregional control. Recurrence due to either subtotal removal or suboptimal treatment may have disastrous consequences for the patient.