Malignant gastrointestinal neuroectodermal tumor, presenting as a second malignancy after gastric adenocarcinoma: a case report and literature review

Malignant gastrointestinal neuroectodermal tumor (GNET), previously known as clear cell sarcoma-like tumor of the gastrointestinal tract (CCSLT-GT), is a rare mesenchymal tumor mainly occurring in gastrointestinal tract (1). In 1985, a tumor in jejunum characterized as “malignant neuroendocrine tumor with osteoclast-like giant cell” was firstly reported (2). Then in 2003, six cases of clear cell sarcomas in gastrointestinal tract were collected and its common features of pathological entity were concluded (3). Microscopically, it is characterized by epithelioid cells with clear or eosinophilic cytoplasm that grow in nest and presence of osteoclast-like giant cells. Immunohistochemically, it usually shows diffuse and strong reactivity for S100 and is negative for cytokeratin, HMB-45, A103. Recently, the translocation of EWSR1 has been documented, and identi？cation of this genetic derangement is useful for diagnosis. Biologically, GNET is extremely malignant and prone to local recurrence and metastasis (4). Nevertheless, its etiology is still not clear. Here we described a case of a 30-year-old woman, who received chemotherapy for gastric adenocarcinoma and subsequently developed a new neoplasm of GNET in the small bowel wall