Mesenchymal tumors are the most common mesenchymal-derived tumors of the GI tract. Most believe that it originates from a type of mesenchymal stem cells (Cajal cells) with multiple differentiation potential, which are found not only in the lining of the GI tract but also in some extra-gastrointestinal structures, such as the omentum and mesentery, so mesenchymal tumors can occur in all parts of the GI tract as well as the mesentery and omentum. Because the tumor cells are mostly spindle cell type (also epithelial and mixed type) under light microscopy, it has been thought to be smooth muscle tumor or nerve sheath tumor in the past. The specific expression of CD117 and CD34 immunomarkers is characteristic of mesenchymal tumors, but CD117 may be negative in the presence of genetic mutations, but DOG-1 is often positive. Ultrasound manifestations 1. Substantial masses of gastric or intestinal wall origin, mostly round or round-like, protruding into or out of the lumen, with a size of several millimeters to more than ten centimeters; 2. Movable masses with moderate to low internal echogenicity, not very homogeneous, and liquid dark areas inside larger masses, occasionally with foci of strong echogenic calcification; 3. The mass may be located outside the submucosal strong echogenic line, indicating that it is of muscular origin, and it is more important to consider the possibility of mesenchymal tumor. 5, intrahepatic metastases are prone to liquefaction necrosis.