Tumeur neuroectodermique gastro-intestinale (GNET) : à propos d'un cas de tumeur du grêle avec métastases hépatiques

The gastro-intestinal neuroectodermal tumor (GNET) is a rare sarcoma of the digestive tract, which was recently recognised. The knowledge of the morphological, immunohistochemical and molecular diagnostic criteria is necessary to not mistake it for the metastasis of a melanoma or for another sarcoma of the digestive tract as the gastro-intestinal clear cells sarcoma or the malignant peripheral nervous system tumor (MPNST). We report the case of a 41-year-old patient with a GNET of the small intestine with hepatic metastasis. The histological examination showed a diffuse proliferation of epithelioid cells, which only express PS100. The presence EWSR1-ATF1 gene fusions with any melanocytic differentiation leads to the diagnosis of GNET.