Why do some people need to take a biopsy during gastroscopy? Does it hurt?

Author: Jin Mulan, Chief Physician, Beijing Chaoyang Hospital, Capital Medical University

Reviewer: Yao Shukun, Chief Physician, China-Japan Friendship Hospital

Gastric mucosal biopsy is mainly a method of obtaining gastric mucosal tissue through gastroscopy for pathological diagnosis.

In recent years, as gastroscopy equipment has become more and more advanced and the diagnostic level of endoscopists has improved, endoscopic examination can detect and diagnose early lesions of the gastric mucosa. However, endoscopic examination alone is sometimes unable to clearly characterize the lesions, and it is necessary to clamp the mucosal tissue and send it to the pathology department. The pathologist observes under a microscope to further diagnose the lesion. The pathologist diagnoses the disease based on histological morphology, and pathological diagnosis is the gold standard.

Figure 1 Original copyright image, no permission to reprint

1. Does gastric mucosal biopsy cause serious damage to the stomach? Does it hurt?

The tissue taken for gastric mucosal biopsy is very superficial and very small, so the damage is very small, almost no damage at all. Generally, the mucosa can return to normal in 1-2 weeks.

Occasionally, a biopsy may cause vomiting blood or black stools, which can usually be relieved on their own. If a large amount of bleeding occurs, you need to see a doctor as soon as possible.

The so-called "painless gastroscopy" means that on the basis of ordinary gastroscopy, a certain dose of short-acting anesthetic is first given intravenously to help the patient quickly enter a state of sedation and sleep, and complete the gastroscopy without any consciousness. Therefore, there will basically be no obvious pain, which is acceptable to the public.

2. Why is immunohistochemistry sometimes performed on gastric mucosal biopsy?

During a gastroscopy, if the endoscopist feels that there is something abnormal in the gastric mucosa, he will take a piece of mucosal tissue and send it to the pathology department for further diagnosis to determine whether it is a tumor lesion.

The gastric mucosa is often irritated and will continuously regenerate and repair itself. However, well-differentiated cancers, especially highly differentiated cancers, are sometimes difficult to distinguish from regenerative changes. In this case, immunohistochemical staining such as Ki67 and P53 may be necessary to assist in the diagnosis of whether the lesion is a tumor or a non-tumor lesion.

Some cancers, such as signet ring cell carcinoma, sometimes resemble histiocytes in morphology. Whether they are histiocytes or true cancer cells, special staining such as PAS, immunohistochemical staining of CK, CD68, etc. may be needed to assist in diagnosis.

Therefore, immunohistochemical staining is often used to assist in making a clear diagnosis.

In addition, the biopsy tissue specimens are dehydrated and wax-immersed, then embedded in paraffin and made into wax blocks. The wax blocks can be preserved for a long time and re-sectioned based on the wax blocks for immunohistochemical staining and special staining without the need for additional biopsies.

3. Can gastric mucosal biopsy determine the type and stage of gastric tumors?

Gastric mucosal biopsy can basically determine the type of tumor, but it cannot determine the stage of the tumor.

Because gastric mucosal biopsy only takes a small piece of mucosal tissue, pathological examination can only qualitatively determine whether it is a neuroendocrine tumor, signet ring cell carcinoma, poorly differentiated cancer, well-differentiated cancer, or lymphoma.

Tumor staging must be analyzed using surgical specimens. Tumor staging includes depth of invasion, lymph node metastasis, and distant metastasis. Biopsy pathological diagnosis cannot see the depth of invasion, nor does it know whether there is lymph node metastasis, so biopsy specimens cannot be used to stage tumors.

4. How long does it usually take for the gastric mucosal biopsy pathology report to be available?

Generally speaking, the report will be issued within 3-5 working days; if immunohistochemistry or special staining is required for auxiliary diagnosis, the report time will be longer.

After the biopsy specimen is sent to the pathology department, the pathologist will take the sample, put the tissue into an embedding box, and then put it into a dehydrator for at least 10 hours. Then it will be embedded and placed in paraffin to form a wax block. The technician will slice it into 3-4 micron thin wax films, put them on glass slides for staining, and only after the tissue sections are made can they be carefully observed under a microscope for diagnosis.

Figure 2 Original copyright image, no permission to reprint

The resident doctor will make the initial diagnosis, and the attending doctor or chief physician will make the follow-up diagnosis. At least two or three level doctors will make the diagnosis. For some difficult cases, the department needs to discuss and get the results. The time required is about 5 working days. If it is a special case, deep cutting, special staining, immunohistochemistry and other methods are required, so the time to issue the report will be extended accordingly.