Gastrointestinal clear cell sarcoma, AKA malignant gastrointestinal Neuroectodermal tumor: an uncommon entity in a young patient presenting with Anemia, Intraabdominal mass and subsequent liver metastasis.

Gastrointestinal clear cell sarcoma is a rare tumor with neuroectodermal differentiation that affects the gastrointestinal tract and involves gene fusion translocations of EWSR1. These tumors predominantly occur in young adults and often display aggressive behavior, with metastases to lymph nodes and the liver. Histologically, the tumor comprises uniform round cells with round nuclei and pale eosinophilic or clear cytoplasm. It exhibits variable mitotic activity and demonstrates positive immunohistochemical staining for S100 and SOX10, while specific melanocytic markers are negative. Currently, no tailored chemotherapy regimen has been identified for this entity. Due to the limited number of reported cases, effective management strategies remain unclear. Here, we present the case of a young adult patient diagnosed with CCS/GNET using immunohistochemistry. The diagnosis was confirmed by next-generation sequencing (NGS), which detected the characteristic EWSR1-ATF1 gene fusion, and liver metastases were identified during follow-up.