Primary intradural Ewing's sarcoma of the spine: a systematic review of the literature

The incidence of extraosseous Ewing's sarcoma, a highly malignant mesenchymal mass, is rare in the spinal cord and its clinical outcomes unknown. To date, few cases of primary intradural extramedullary Ewing's sarcoma (PIEES) have been reported, with varying follow-up. Herein, we aimed to perform a comprehensive review of all cases published in the literature and update previously reported cases from our institution. Institutional medical records were searched for cases of PIEES of the spine managed at our institution between the years 2005 and 2018. We performed a systematic search of two electronic databases (Ovid Medline and Embase) from inception to August 2018 to obtain all published cases of primary intradural extraosseous Ewing's sarcoma (PIEES).We used our institutional medical records to update cases reported from our institution. We identified a total of 44 cases with pIEES reported in the existing literature of which 5 have been from our department. Of the 41 cases, the median age of diagnosis was 31 years. The most common presentation pattern was PIEES in the lumbar/sacral region (61%, n = 27), with a majority (59%, n = 25) presenting initially with pain. The most common modality of treatment reported was surgery (41/41, 100%), followed by adjuvant chemotherapy (31/44, 70%) and local radiation therapy (29/44, 66%). Overall, recurrence was reported in 17/36 (46%) cases, with median progression free survival (PFS) of 12 months (range, 1-72). There were 12/37 (32.4%) deaths reported, with median overall survival (OS) of 14 months (range, 1-72). Hence, we present the most updated review of all reported cases of PIEES. While surgical resection is the mainstay of treatment, tumor recurrence is a great concern given the adhesive nature of the lesion preventing complete resection. Adjuvant chemotherapy and radiotherapy should be carefully considered to prevent recurrence and improve survival outcome.