Olfactory schwannomas are rare tumors of the anterior skull base that are possibly derived from ectopic Schwann cells, perivascular neural tissue, or sensory nerves of the meninges. The authors report the case of a 14-year-old boy with an olfactory schwannoma that extended inferiorly through the cranial base and superiorly into the frontal lobe. Because of the growth characteristics of the tumor and the significant overlying frontal lobe edema, the lesion was approached via an endonasal endoscopic route, as a strategy to minimize brain retraction. This tumor was characterized radiographically as contrast-enhancing with cystic areas and erosion into bone. The tumor showed immunoreactivity for S100 protein and leukocyte antigen 7 (CD57) but not epithelial membrane antigen, supporting the diagnosis of olfactory schwannoma. A gross-total resection was achieved. This approach represents a novel application of endoscopic endonasal surgery to the pediatric neurosurgical context, as well as a favorable outcome in an extremely unusual tumor type, that should be applicable to other appropriately selected pediatric brain tumors.
Hilal A. Kanaan, Paul A. Gardner, Gabrielle Yeaney, Daniel M. Prevedello, Edward A. Monaco III, Geoffrey Murdoch, Ian F. Pollack and Amin B. Kassam
Amin Kassam, Ajith J. Thomas, Carl Snyderman, Ricardo Carrau, Paul Gardner, Arlan Mintz, Hilal Kanaan, Michael Horowitz and Ian F. Pollack
The authors reviewed their experience with endoscopic approaches to determine their safety and efficacy in the treatment of pediatric patients who harbor skull base lesions. Although they were interested in ascertaining outcomes after surgery as well as validating and defining indications and limitations of these approaches, the authors recognized that the follow-up duration was inadequate to assess long-term outcomes.
The authors conducted a retrospective review of all endoscopic procedures performed at their institution between January 2000 and September 2005. The procedures were categorized into a series of anatomical modular approaches.
Twenty-five patients 18 years of age or younger were identified. The surgical goals were individualized and included gross-total resection, partial resection, biopsy, decompression of neural structures, and repair of a cerebrospinal fluid (CSF) leak. One patient required an open procedure in addition to the expanded endonasal approach for definitive therapy. No patient suffered a neurological deficit, vascular injury, or central nervous system infection. A CSF leak was the most common complication and occurred in two (8%) of the 25 patients.
In well-selected patients, the expanded endonasal approach represents a safe, effective, and minimally invasive technique for the treatment of skull base lesions in children. Incremental experience is needed for acquiring the skills with endoscopic techniques to progress to the more complex modular approaches.