1. What is the relationship between gastrointestinal mesenchymal tumors and smooth muscle tumors of the gastrointestinal tract?
Gastrointestinal mesenchymal tumors and gastrointestinal smooth muscle tumors as well as gastrointestinal neurogenic tumors are all gastrointestinal mesenchymal-derived tumors.
About 73% of the gastrointestinal mesenchymal-derived tumors are gastrointestinal mesenchymal tumors.
2.Is there any benign and malignant gastrointestinal mesenchymal tumor?
The World Health Organization (WHO) classifies gastrointestinal mesenchymal tumors as benign, potentially malignant and malignant.
There are no obvious criteria to distinguish benign from malignant.
most consider gastrointestinal mesenchymal tumors to be non-benign, or at least of low malignancy
Although less than 2cm is mostly benign, the diagnosis needs to be carefully made and relates to how much scope of resection.
3.Is gastrointestinal mesenchymal tumor suitable for needle aspiration biopsy?
It is generally not advocated because of its susceptibility to rupture.
The amount of needle aspiration tissue cannot meet the requirements, and it is difficult to identify benign and malignant (50 high magnification fields of nuclear splitting phase are required).
However, without preoperative biopsy, immunohistochemical examination cannot be performed and the diagnosis cannot be confirmed
Frozen section cannot confirm the diagnosis, but can only clarify the general tissue cell characteristics.
4. What are the general morphological features of gastrointestinal mesenchymal tumors?
Tumors vary in size, 0.8-20 cm in diameter, and can be solitary or multiple.
Mostly located in the submucosa (60%), subplasma layer (30%) and muscle wall layer (10%) of the gastrointestinal tumor.
The boundary is clear, without envelope or with pseudo-envelope.
5.What is the relationship between different sites of gastrointestinal mesenchymal tumors?
Stomach 60%-70%, small intestine 20%-30%, colorectum <5%, esophagus <5%.
The prognosis of extragastric (small intestine, colorectal) mesenchymal tumor is worse than that of gastric mesenchymal tumor.
6.What is the difference between GIST metastasis and general gastrointestinal cancer?
Lymph node metastasis is less common (3% to 4%) – different from the lymphatic metastasis predominant feature of gastrointestinal cancer.
metastasis is more common with abdominal implantation and liver metastasis.
Generally, lymphatic dissection is not done, and joint organ resection is not done, and a cut margin of more than 2 cm is sufficient.
7.Characteristics of GIST imaging?
Gastroscopy: the tumor is seen as a spherical or hemispherical bulge, and routine gastric mucosal biopsy is often negative.
Endoscopic ultrasound (EUS): can clarify the tumor site and size.
X-ray examination: round-like filling defects and niches can be seen.
CT and PET-CT examination can find small lesions of 1cm in diameter, and can also determine whether there are metastases.
8.Surgery for GIST?
Surgical resection is the only curative method for GIST due to the extremely poor results of conventional chemotherapy and radiotherapy (less than 5%).
The surgical goal is to try to achieve R0 resection , 85% of patients with primary GIST can receive radical surgical resection.
confined GISTs greater than 2 cm are, in principle, amenable to surgical resection.
While complete resection of the tumor, tumor rupture and intraoperative dissemination should be avoided.
9.What about GIST recurrence, metastasis and unresectable?
High rate of postoperative recurrence and metastasis, with 50% recurring within 5 years after surgery.
About 3/4 local recurrence, half with simultaneous peritoneal metastasis and liver metastasis.
For tumor recurrence and controllable risk, secondary surgery is possible.
10.Molecular targeted drug therapy for gastrointestinal mesenchymal tumor?
Gastrointestinal mesenchymal tumors with recurrent metastases that cannot be resected are treated with imatinib (standard first-line therapy) – resulting in clinical benefit in 84% of patients
10-15% of GISTs with primary resistance to imatinib.
? Sunitinib is a second-line molecularly targeted therapy for gastrointestinal mesenchymal tumors.