Abstract General Information

Title

ROLE OF NEOADJUVANT CHEMOTHERAPY IN REDUCING SURGICAL MORBIDITY IN A YOUNG CHILD WITH A RARE PRIMARY SKULL BASE EWING’S SARCOMA

Case Presentation, Discussion, and Final Comments.

Ewing’s Sarcoma is an aggressive form of childhood cancer that is the second most common bone tumor in this population. Skull base Sarcoma is very rare and account for only 1% of all Ewing’s Sarcoma. There are no established treatment protocols.
Case presentation: We present a case of a three year of age female diagnosed with an infiltrative bone lesion in the cribriform plate extending into the nasal cavity and left orbit, causing proptosis and visual acuity loss. Due tumor fast-growing rate we decided to perform an endonasal-transethmoidal biopsy confirming a primary skull base Ewing sarcoma. The patient was submitted to “off-label” neoadjuvant chemotherapy, according to the protocol of the South American study for the treatment of patients with non-metastatic Ewing tumors (2016) that mixed vincristine, adriamicine, ciclosfosfamide, ifosfamide, etoposide and vimblastine. A significant tumor reduction was achieved after 6 cycles of chemotherapy, with a small residual lesion in the cribriform plate. To avoid radiotherapy, the patient was submitted to a combined (endonasal and transcranial) approach with extensive removal of the anterior skull base, dura mater, olfactory bulb with additional decompression of the left orbit and optic nerve. Pathology confirmed free margins at the resection cavity and periorbita. The patient was treated with adjuvant chemotherapy (8 cycles cycles) and radiotherapy was precluded. At present date, she has one year of follow up free of progression disease, presenting normal vision and only anosmia as permanent neurological deficits.
Discussion: Ewing sarcoma is a rare type of cancer that make up 1% of all kinds of cancer in childhood and only 1% of them are located at the skull. It is classified as a primitive neuroectodermal tumor, and prompt diagnosis and treatment are essential for long term survival. Resection of the tumor should be as radical as possible to achieve negative margins, minimize tumor mass and enhance the effect of adjuvant therapy.
Final comments: this case report demonstrate a potential benefit of neoadjuvant chemotherapy for skull base Ewing's sarcoma, and its importance in reducing the surgical morbidity and mortality by allowing free margin resection. No standard treatment are current available. However, as sinonasal undifferentiated carcinoma, neoadjuvant chemotherapy may have an important role this challenging cases.

Keywords

Ewing sarcoma, Skull base, Pediatric neurosurgery, Pediatric oncology.