Three Common Methods of Endoscopic Biopsy and Cytology

Three Common Methods of Endoscopic Biopsy and Cytology

No.1 Direct Biopsy

 

Biopsy under direct vision of endoscope should be performed after observation photography to avoid affecting the effect of observation and photography.

 

The biopsy forceps should be brought into the field of vision.

 

Generally, it is most appropriate to make biopsy with the pliers head extended 1-2cm, and the direction of the head should be perpendicular to the target tissue.

 

Generally, take 2-3 pieces tissues from inflammatory lesions, and take 4-6 pieces tissues from ulcer and tumor lesions. The first piece of tissue has the highest successful rate in pathological meaning. Do not take tissues from the necrotic tissue. Generally mucosal tissue around the lesion should be taken.

 

No.2. Cytological examination

 

When the lumen is severely narrowed or the lesion is relatively limited, the positive rate of biopsy can be affected, while the microscopic cytology can make up for the above deficiencies. All cytological examinations should be performed after endoscopic observation and biopsy. The methods of cytology under endoscopy are as follows.

1. The method of cell brush inspection under direct vision: remove the biopsy valve on the endoscope and replace it with a cell brush valve (in which the rubber pad hole is large enough to pass through the cell brush). Extend the cell brush to the lesion through the endoscope channel. Brush it gently on the lesion.

The scope of brush test can be larger and wider. Constantly rotate the spring steel wire of the cell brush during the sampling, so that all sides of the brush head can obtain cells.

Brush strength should not be too large so as not to hurt the gastric mucosa,or lead to hidden bleeding and other complications.

After brushing, gently pull the cell brush to the exit of the endoscope, exit the device with endoscope. Extend the brush head, and smear the brush from left to right in the center of the glass slide from top to bottom. If there were too much blood and mucosa on the head, use cotton to clean before smearing it on the slide.

Simultaneously rotate the direction of the brush head, general smear 4-6 pieces. Fix the slide immediately after the sample is dry. (The solution used for fix is 95% ethanol and half ether)

 

 

2. Inspection of tissue plates

This method is relatively simple. Small tissue blocks obtained from biopsy are placed on the glass slide, make several times gentle pressure before fixation.

Then fix it and stain it.

The positive rate of the plate examination is slightly lower than that of the biopsy, but the cell morphology examination can make up for the deficiency of the biopsy.

 

 

No. 3 . Large mucosa biopsy

 

 

Endoscopic diagnosis depends on the accuracy of histology, and then conventional biopsy forceps technology often cannot meet the requirements of accurate diagnosis. For suspected malignant lesions, when general biopsy and cytological examination cannot be clear, large mucosal biopsy technology should be adopted.

 

Reliable large mucosal biopsy techniques can also be used to treat early gastrointestinal cancers. Various large mucosal biopsy techniques are collectively referred to as endoscopic mucosal resection. (Endoscopic mucosal resection, EMR)

 

1. Principles of large mucosal biopsy

The purpose of large mucosal biopsy is to obtain enough target tissue safely without causing serious complications. Therefore, saline should be injected into the sub mucosal of the biopsy site in advance to separate the mucosa from the underlying tissues. This reduces the effect of high-frequency currents on the underlying tissues. In addition, for sunken or flat lesions, sub mucosal injection can elevate the tissue for ease of operation.

 

 

2.Operation methods: 3~5ml normal saline (or 1:10,000 adrenalin normal saline) was injected into the sub mucosal layer of the target lesion through an endoscopic injection needle to make the lesion uplift. Due to the infusion pressure, the sub mucosal muscular mucosa layer and the intrinsic membrane on the intrinsic muscle layer were separated.

Fix the snare on the proper position, use biopsy forceps to grasp the protruding mucosa and tighten the snare. The mucosa layer could be dissected by high-frequency current. Double-cavity endoscopy (OLYMPUS gif-2t10 or git-2t200) is usually used to safely remove all the mucosa and a considerable part of the sub mucosal tissues as long as 2-3 cm.

 

If the lumps are too large to be completely removed at one time, this operation may be performed in several times. The suction tube was installed at the front end of the endoscope is for this purpose of operation. Conventional single-channel endoscopy could also be used. However, in this way, the size of the resected tissues was not significantly improved. The needle with insulated tip can remove large lesions, but the perforation rate is high.

 

Common complications include bleeding, ulcers, and perforation. Ulcers left after large mucosal biopsies are usually not at risk of perforation unless the duration of the current time is too long. In order to prevent bleeding, thrombase could be sprayed under the endoscope on the wound surface. Masahiro Tada, a Japanese scholar, conducted 3000 cases large mucosal biopsies, only one of which was perforated, and bleeding accounted for 1% (30/3000). All the bleeding cases were controlled well with hemostasis clips. To prevent bleeding, ulcers can also be clamped with titanium clips, which also helps ulcers heal. For small perforations, titanium clamps can also be used.

 

Therefore, large mucosal biopsy becomes routine endoscopic surgery. Perform routine treatment methods of anti - ulcer therapy after operation. H2 antagonist or proton pump inhibitor can be used. Patients should rest in bed for 1 day after the operation.

 

Endoscopic Diagnosis and Treatment Key Points by Chinese Endoscopic Journal.