Clear cell sarcoma of the ileum: report of a case and review of the literature.

Introduction: Clear cell sarcoma of the gastrointestinal tract (CCS-GI) is an extremely rare and aggressive tumor, which often mimics other neoplastic processes. Because of this feature, its real incidence may have been underestimated, especially in the past when genetic tests were less available than nowadays. To date, less then 30 cases have been described in the literature on the GI tract.
Case Presentation: We report the case of a 69-year-old woman who presented with active rectal bleeding. After a negative colonoscopy, the patient underwent a video-capsule endoscopy. The latter detected an ileal mass that was surgically resected. The microscopic appearance was consistent with a malignant mesenchymal neoplasm; immunohistochemistry was positive for S100 protein, CD56, and INI1. Fluorescence in situ hybridization showed a translocation involving the EWSR1 (Ewing sarcoma 1) gene region. All these findings were consistent with a CCS-GI.
Conclusion: Herein we present a case of CCS-GI, discuss its clinical and pathological features, and review the literature on the subject.