Malignant Tumors of the Anterolateral Skull Base

Abstract

Malignancies of the anterolateral skull base are clinically and pathologically distinct from those of the central anterior skull base and the temporal bone. The purpose of this report is to describe the outcomes and complications after skull base surgery and multimodality therapy in a group of patients with anterolateral skull base malignancies. PATIENT DATA AND METHODS: The mean duration of follow-up for living patients was 57.2 months (median, 56.8 months). The median age of the 52 patients who met the inclusion criteria for this study was 47 years (range, 1-81 years). The most common presenting feature was cranial nerve palsy (60%). Of these cranial nerve palsies, trigeminal neuropathies causing facial numbness were the most common, with V2 being affected in 35%, V3 affected in 33%, and V1 affected in 17%. Abducens neuropathy was present in 14% of patients. The most frequently occurring pathologies after the various sarcomas were squamous cell carcinoma (SCC) and adenoid cystic carcinoma (ACC) in 23% and 14% of patients, respectively. Of the 30 sarcomas, 16 were classified as low grade and 14 were classified as high grade. Complications of treatments were identified in 16 patients (31%). Ten patients had a single complication, whereas 6 patients experienced multiple complications. The most common complications were a new or worsened cranial nerve deficit (n = 4), pneumonia (n = 4), and flap necrosis (n = 3). Recurrence after the treatment associated with the index surgery occurred in 37 patients (71%). The recurrence was local in 30 patients (58%), both local and distant (metastatic) in 4 patients (8%), and only distant in 3 patients (12%). The median progression-free survival (PFS) was 2.1 years (range, 1.2-3.0 years). Median PFS times of 0.6 and 1.6 years were noted for patients with high-grade sarcoma (HGS) and low-grade sarcoma (LGS), respectively. The mean PFS (median not reached) for the patients with SCC was 4.6 years, whereas the median PFS for patients with ACC was 3.3 years. The overall 2- and 5-year survivals for all patients were 81% and 53% (median, 5.0 years; 95% confidence interval, 3.9-6.1 years), respectively. The median survival for patients with nonsarcomas was 6.9 years, the 2-year survival was 82%, and the 5-year survival was 55%. Patients with HGS survived the shortest time (median, 3.3 years; 2-year, 64%; 5-year, 27%), whereas those patients with LGS had an intermediate survival (median, 5.3 years; 2-year, 94%, 5-year, 72%). It is our belief that anterolateral skull base malignancies comprise a distinct group of tumors. These lesions should be analyzed separately from central anterior skull base lesions and temporal bone malignancies. With a multimodality treatment protocol, acceptable survivals may be obtained that are comparable to results that have been reported for tumors involving less difficult areas of the skull base.