Two rare presentations and treatments of Ewing's sarcoma: A need for a standard treatment approach.

Abstract

e21000 Background: We describe two Caucasian boys with rare presentations of non-metastatic Ewings sarcoma (ES) with atypical primary sites. One was extradural but FISH negative for 22q11.2. Another was intradural but extramedullary, and FISH positive. Literature search showed few publications which describe such cases, and there is currently no standard of care. Methods: MG, an 11 year old male, presented with a frontal skull mass, with an intracranial epidural extension of about 5 mm. Biopsy confirmed ES. MG was treated with Vincristine, Doxorubicin, and Cyclophosphamide, alternating with Ifosfamide and Etoposide every 2 weeks, for 6 weeks. He underwent tumor excision for local control with good response. Chemotherapy continued, completing 14 cycles total. He is in remission 15 months after completion. AH, a 13 year old male, presented with lower back pain and paraesthesias of feet. MRI revealed an intradural, extra-medullary L1-L3 mass. Intra-operatively, all visible tumor peeled off readily, except for the L2 nerve root. The tumor was FISH positive for EWSR1. He was treated with the same regimen as MG for 6 cycles. Local control was done with radiation. He then continued chemotherapy, completing a total of 14 cycles. MRI scans 3 months later revealed enhancing intradural lesions along the spinal cord (involving C5, T5 and T8) and two lesions along the cerebellum. He was started on cyclophosphamide and topotecan and has completed 8 cycles without disease progression. Results: MG was diagnosed based solely on histo-pathological diagnosis. While MG’s lesion was extra-osseus in nature, more unusual presentations demonstrate the importance of molecular diagnostic techniques. AH was diagnosed based on chromosomal analysis. Progression is presumably from microscopic residual disease in intradural space that invaded CSF. He is presently on salvage chemotherapy. Nine months after relapse, disease is stable, with plans to minimize disease and consolidate. Conclusions: Intradural tumors tend to progress rapidly, maybe more so than extradural tumors. Future suggestions include developing a standard approach that will improve both treatment of Ewing’s sarcoma and prognostic outcomes for rare initial presentations.