Malignant Gastrointestinal Neuroectodermal Tumor: A Case Report and Literature Review

Introduction: The gastrointestinal neuroectodermal tumor (GNET) is a rare mesenchymal tumor mainly arising in the gastrointestinal tract. Case Presentation: Herein, we describe a case of GNET that had been previously diagnosed as metastatic primitive neuroectodermal tumor (PNET) to the lung and liver and received 30 cycles of adjuvant chemotherapy. The physical exam showed a palpable mass in the lower right quadrant of the abdomen. The tumor mass was composed of diffuse sheets of epithelioid tumor cells, in which osteoclast-like giant cells scattered unevenly. Immunohistochemically, the tumor cells were diffusely positive for SOX10, CD99, and CD56, patchy positive for pan-CK, and negative for desmin, HMB-45, Melan-A, and chromogranin. Conclusions: Consistent with previous studies that reported a secondary GNET following chemotherapy, we assume that the chemotherapy might trigger the tumorigenesis of GNET in this case.