Abstract
Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare soft tissue sarcoma, previously referred to as clear cell sarcoma-like gastrointestinal tumor (CCSLGT) and also commonly reported in the literature as clear cell sarcoma of the gastrointestinal tract (CCS-GI). The current study reports a case of GNET arising in the stomach of a 17-year-old male, who presented with symptoms of fatigue, anemia and low temperature. Examination with positron emission tomography-computed tomography revealed a soft tissue mass in the gastric antrum. Subsequently, radical distal gastric resection was performed, and the mass measured 6.0×4.0×3.5 cm3. Histopathological analysis revealed that the tumor cells were arranged in nests and focally formed fascicular, pseudopapillary, pseudoalveolar and rosette-like growth patterns. Osteoclast-like giant cells were also observed. Immunohistochemically, the tumor cells were positive for S-100 protein, vimentin and BCL-2, and negative for HMB45, Melan-A, CD117, CD34 and CD99. Additionally, the osteoclast-like giant cells were positive for CD68. Fluorescence in situ hybridization demonstrated EWSR1 gene rearrangement. After 10 months of follow-up, no evidence of recurrence or metastasis was observed. As GNET is currently classified differently and under various names in the literature, the information provided by this case study and review is predicted to be useful towards the accurate diagnosis, treatment and prognosis of this rare tumor type.
Highlights
Malignant gastrointestinal neuroectodermal tumor (GNET), named by Stockman et al [1] in 2012, is a rare tumor of the gastrointestinal tract
The current study reports a case of GNET in the stomach and reviews the literature, focusing on similar cases and tumor classification
In a review of the literature, the majority of clear cell sarcoma of the gastrointestinal tract (CCS‐GI) cases were found to be cases of GNET; we hypothesize that GNET and Clear cell sarcoma (CCS) represent two distinct tumor types
Summary
Malignant gastrointestinal neuroectodermal tumor (GNET), named by Stockman et al [1] in 2012, is a rare tumor of the gastrointestinal tract. Researchers have demonstrated that the tumor has obvious characteristics of melanocytic differentiation, but differs from malignant melanoma with respect to clinical, genetic and biological factors. A number of CCS cases in the gastrointestinal tract were reported successively, the majority of which lacked melanocytic differentiation features, and were commonly reported as CCSLGT. Positron emission tomography‐computed tomography examination revealed a soft tissue mass in the gastric antrum, which exhibited increased fluoride deoxidization glucose. The gastroscopy results revealed irregular hyperplasia at the gastric antrum, as well as ulcers and signs of necrosis Due to these observations, a radical distal gastric resection was performed. The tumor cells were negative for HMB45 and Melan‐A, which are markers of melanocytic differentiation (Fig. 2B). The proportion of cells exhibiting an abnormal signal indicating the genetic disruption of EWSR1 was 71% (Fig. 2D)
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