Long-term Outcomes in the Treatment of Pediatric Skull Base Chordomas in the Endoscopic Endonasal Era

Objective: Pediatric skull base chordoma is a rare entity that is traditionally considered to display aggressive behavior with an increased risk of recurrence. There is an absence of literature examining outcomes in the pediatric population in general and using the endoscopic endonasal approach (EEA).

Methods: The authors retrospectively reviewed all patients with skull base chordomas presenting by the age of 18 years to the Children's Hospital of Pittsburgh or the University of Pittsburgh Medical Center from 2004 to 2019. Clinical outcomes, the number and location of recurrences, and progression-free survival time were determined.

Results: Twenty patients met the study criteria. The most common presenting complaints were diplopia (n = 7), headache (n = 6), and swallowing difficulty (n = 4). Three cases were incidentally discovered. Twelve patients underwent single-stage EEA alone, 2 patients had two-stage EEA, and 6 patients had combined EEA with open far-lateral or extreme-lateral approaches. Fourteen patients underwent gross-total resection (GTR), and 6 patients had near-total resection. Larger tumors were more likely to require staging or a combined approach (86% vs 7%) and were less likely to receive GTR (33% vs 86%) but had comparable recurrence and mortality rates. Five patients developed CSF leaks requiring reoperation, 2 patients developed a permanent abducens nerve palsy, 1 patient suffered an internal carotid artery injury, 1 patient developed an epidural hematoma, and 1 patient developed a subdural empyema. Four (20%) patients had recurrence during follow-up (mean radiographic follow-up 59 months and mean time to local recurrence 19 months). Two patients with recurrence underwent further resection, and 1 patient elected to stop treatment. Both patients who underwent repeat resection experienced a second recurrence, one of whom elected to stop treatment. Both patients who died had an elevated Ki-67 (p = 0.039), one of whom developed de-differentiated histology. A third patient died of progressive spinal metastases without local recurrence and is one of 2 patients who developed postoperative spinal metastases. Both patients whose tumors became de-differentiated progressed from tumors with an initial Ki-67 of 15 or greater (p = 0.035) and received prior radiotherapy to the bulk tumor (p = 0.03).

Conclusions: The majority of pediatric skull base chordomas, when managed at a specialized center with a goal of GTR, may have a better outcome than traditionally believed. Elevated Ki-67 rates may predict poor outcome and progression to de-differentiation.