I. Origin of gastrointestinal mesenchymal tumors
Gastrointestinal stromal tumors (GIST) are tumors that originate from mesenchymal stem cells in the gastrointestinal tract and are positive for c-kit gene, CD117 and CD34. GIST can also occur outside the gastrointestinal tract, such as the greater omentum, mesentery and pelvis.
Second, how to determine the benignity and malignancy of gastrointestinal mesenchymal tumor
Nowadays, GIST can be classified as benign, potentially malignant, and malignant. Malignant indicators include.
1.Tumor is infiltrative, i.e. invade the surrounding organs;
2. The tumor has metastasis to distant organs;
3. The maximum diameter of the tumor reaches or exceeds 10 cm.
Indicators of potential malignancy include.
1. Gastric mesenchymal tumor is larger than 5 cm in diameter and intestinal mesenchymal tumor is larger than 4 cm in diameter;
2. 5 nuclear schizograms/50 HPF for gastric mesenchymal tumor and ≥1 nuclear schizogram/50 HPF for intestinal mesenchymal tumor;
3.Tumor appears necrosis;
4.Tumor cells have obvious heterogeneity;
5.Tumor cells are actively growing and densely arranged. When the tumor has 1 malignant index or 2 or more potentially malignant indexes, it is malignant GIST; when there is only 1 potentially malignant index, it is junctional GIST, otherwise it is benign GIST. the maximum diameter of the tumor shown in the attached figure is greater than 10 cm, the tumor has necrosis, and the tumor is found to invade the small intestine, sigmoid mesentery and bladder during surgery.
3. How to diagnose gastrointestinal mesenchymal tumor?
Before surgery, the main diagnosis relies on CT and other imaging diagnosis (see Figure 1 and Figure 2), and after surgery, the malignancy of tumor mainly relies on conventional pathological diagnosis, immunohistochemical staining and genetic diagnosis.
What are the treatments for gastrointestinal mesenchymal tumor?
The complete resection of GIST tumor is a very important factor that affects the survival time of patients. The complete resection of the tumor depends on many factors, such as the size of the tumor, the presence of distant metastases or intra-abdominal implants, and whether it infiltrates the surrounding tissues and organs. Therefore, for tumors that cannot be completely resected for the first time due to various reasons, targeted therapy can be used preoperatively and surgical resection can be performed after the tumor shrinks, thus improving the complete resection rate of the tumor. Rupture of tumor is one of the factors of poor prognosis. Giant GISTs are highly susceptible to rupture during surgery, so excessive traction or squeezing of the tumor should not be done to avoid rupture or intra-abdominal implantation of the tumor.
Molecularly targeted drugs have greatly changed the prognosis of mesenchymal tumors. Currently, the main molecularly targeted drugs for the treatment of mesenchymal tumors are imatinib and sunitinib. Their indications include: surgically unresectable or recurrent mesenchymal tumors; preoperative neoadjuvant therapy with the aim of shrinking the tumor to achieve complete resection; and adjuvant therapy after surgery for highly aggressive tumors.
Figure 1. Coronal view, seen with tumor blood supply from the ileocolic artery and tumor with necrosis.
Figure 2. Cross-sectional view, the tumor is closely related to the posterior abdominal wall and the maximum diameter of the tumor is greater than 10 cm.