Forceps Sizes

The most common pinch biopsy forceps used worldwide is one that fits through a 2.8-mm biopsy channel. Infants and very young children often have biopsy specimens taken with a smaller forceps that fits through a 2.2-mm biopsy channel. Pediatric gastroenterologists generally use narrow-bore instruments for routine diagnostic biopsy if the child weighs less than 10 kg.

The aim with pinch biopsy forceps is to obtain a biopsy specimen that contains the full thickness of the mucosa in disorders not associated with a large increase in mucosal thickness, such as hypertrophic gastropathies. The 2.8-mm channel biopsy forceps can generally obtain a full-thickness mucosal specimen except for the greater curve of the gastric body, where the folds are normally thickest.

Larger Capacity Forceps

The large-cup (“jumbo” or “max capacity”) forceps requires a large channel, a so-called therapeutic endoscope (biopsy channel 3.6 to 3.7 mm). Some newer designs are intended to provide larger biopsy specimens with the conventional 2.8-mm channels and intermediate-sized channels such as pediatric colonoscopes.¹ Larger capacity biopsy forceps are highly desirable to optimize the diagnostic yield. Part of the reason that only a few endoscopists have used the large-cup forceps is the reluctance to use larger capacity forceps that require the larger channel. There is also a puzzling antipathy toward the use of a larger forceps that obtains superior sized specimens. Studies have been done to show that a larger forceps is unnecessary, as if the larger forceps represented a serious threat or a “ploy.”²

Larger capacity forceps biopsies yield two to three times the surface area but are not generally much deeper (Fig. 5.1).The main objective with biopsy is not to obtain more representative sampling of a whole organ but to enable the histotechnologist to see the biopsy specimens to orient them (see Fig. 5.1). Histotechnologists cannot orient small to tiny specimens. The resultant sections with larger capacity forceps are infinitely superior. Proper orientation during paraffin embedding is impossible with often delivered “fleabite”-sized specimens as part of a group of biopsies in a tissue block.

Fig. 5.1 The advantage of a larger capacity forceps is not to sample more terrain (e.g., in surveillance in Barrett’s esophagus and ulcerative colitis) but to provide larger sized biopsy specimens so that the histotechnologist can orient the specimens for embedding, on edge. That is more difficult with small specimens. With tiny biopsy specimens, it is impossible.

Orientation for embedding in paraffin is the key to maximizing the diagnostic yield from mucosal biopsies. Orientation with crypts and villi are lined up and not cross cut like a stack of doughnuts. This orientation permits assessment of the amount of lamina propria inflammation, focal lesions such as granulomas, and intraepithelial lymphocytes (especially small bowel). In the colon, oriented sections permit assessment of crypt branching (architectural distortion) for differential diagnosis regarding chronicity and assessment of lesser grades of dysplasia by being able to use crypt architectural disorganization as opposed to only cytologic change in cross-cut sections. Oriented sections are required to maximize the yield for focal lesions.

Biopsy specimens taken with larger capacity forceps usually contain very little submucosa or none at all. It is sometimes difficult to obtain specimens with sufficient submucosa when the objective is to diagnose amyloid or rule out or hunt for vasculitis in submucosal blood vessels.

Multiple Biopsy Specimen Forceps

Multibite forceps are designed to obtain multiple specimens with a single pass. They may be judged as adequate by some pathologists, but for what purposes? Biopsy specimens are generally tiny and pale compared with the quality of specimens of other forceps biopsies. The aggregate tissue is considered one advantage, but that does not guarantee any higher yield when the aggregate nets multiple tiny cross-cut sections.

How Close to the Biopsy Site the Endoscope Should Be Positioned

After biopsy targeting of focal lesions in disorders such as mucosa-associated lymphoid tissue, Barrett’s esophagus, and ulcerative colitis, random biopsy specimens can be taken using landmarks or measurements. In these biopsy “mapping” circumstances, it is unnecessary to be close to biopsy sites or to clean each putative biopsy site of mucus or blood that has seeped over from adjacent biopsy sites. The biopsy specimens can in a sense be taken blindly based on measurements or position, after the area has been cleared by biopsy of focal lesions.

Pressure against the Wall

Less tension on the wall helps obtain better-quality biopsy specimens. After the opened forceps is pressed against the wall, it is almost a reflex action to give it a second push into the wall. This unnecessary stretch may result in a shallower or traumatized biopsy specimen. The endoscopist should try to take specimens of folds or valvulae or partially deflate the lumen beforehand or after applying the forceps to the mucosa. Deflation can be achieved very quickly with a few bursts of staccato suction before clamping down on the tissue.

Snapping the Forceps Back Quickly after It Is Closed on the Tissue

There is often an inclination (or urge) to pull back to tent the mucosa surrounding forceps with the trapped biopsy specimen. This urge should be resisted, and the forceps should be snapped back quickly. A delay in snapping the forceps closed and pulling out the forceps quickly may provoke more crush artifact of the tissue.

Double Bites

The term double bites refers to taking two specimens with a single pass of the biopsy forceps. With conventional-sized forceps, this double-bite technique often yields a tiny second biopsy specimen, or a “macrocytology” (Fig. 5.2). However, the double-bite technique may be used successfully in the colon in ulcerative colitis biopsy surveillance and in the small bowel using a larger capacity forceps. In the esophagus, the double-bite technique is difficult because of the need for angulation and risk of loss of the first biopsy specimen obtained. In the stomach, the size of the specimens is often so generous with the first pass that there is scant room for a second biopsy.

Fig. 5.2 Double-bite inadequate-sized biopsy specimens in Barrett’s esophagus. A, Specimen at the lower left is the only one that can be oriented, and it is superficial. The others are scrapings. B, One of the fragments (inset in A enlarged) shows high-grade dysplasia.

To perform this technique, after the first biopsy specimen is obtained, the closed forceps is placed with slight pressure on the wall where the next specimen is to be taken and is opened against a bit of wall pressure. This pressure helps prevent the first specimen from falling out into the lumen. After opening the forceps poised to biopsy, a few staccato bursts of suction are applied, and then the forceps is closed quickly to obtain the second specimen. One does not always obtain two biopsy specimens. I usually obtain two specimens about once in three to five times.

Turn-in Technique

In areas where one has to perform a biopsy at an oblique angle, as in the esophagus or for gritty lesions, it helps enormously to use the turn-in technique. The opened forceps is first drawn back flush with the endoscope tip. The tip of the endoscope is then deflected 90 degrees against the wall, allowing the forceps to be advanced en face by moving the endoscope in, rather than extending the forceps. It is advanced until resistance is met, then suction is applied briefly, and the forceps is closed. It is not necessary to see what is being biopsied if any targeted areas were cleared with biopsies as in Barrett’s esophagus surveillance. In the case of a focal lesion, the endoscope is positioned right over the lesion and turned into it using the large up-down hand control knob on the endoscope. For endoscopists who want experience with the turn-in technique, the best way to obtain it is to try it in more spacious areas, such as the stomach, in the course of performing gastric biopsies.

6 O’clock Position and Biopsies of Gastroesophageal Junction (Cardia) Lesions

When areas are difficult to get at, rotation of the endoscope to the 6 o’clock position makes it infinitely easier to obtain biopsy specimens and to target more accurately (Fig. 5.3). This position is especially invaluable in biopsy surveillance of Barrett’s esophagus where the 12 o’clock position tends to be ignored for visualization and biopsy targeting. The endoscope is rotated so that what was at 12 o’clock is now at 6 o’clock.

Fig. 5.3 Value of viewing cardia lesions on retroflexion from the gastric side and positioning at 6 o’clock. A, End-on view of eccentric Z line. B, Retroflexion view in the stomach. Eccentric part is positioned at 6 o’clock. Biopsy, if indicated, is easier from this aspect. C, Small gastroesophageal junction mass as viewed from the stomach on retroflexion and rotated to the 6 o’clock position for biopsy.

For lesions at the gastroesophageal (GE) junction, it is often invaluable to visualize the area on turnaround in the stomach and target biopsy or endoscopic resection from this perspective (see Fig. 5.3C). This maneuver works only if the patient has a hiatal hernia. After the turnaround is done in the stomach, air insufflation is set on high. The endoscope is advanced by slowly withdrawing until the endoscope tip advances right to the GE junction. In this way, there is end-on visualization of a lesion. Additionally, the endoscope can often be torqued slightly to place the lesion in or near the favored 6 o’clock position (see Fig. 5.3). If torque is required for biopsy positioning, the endoscopy assistant maintains it while the biopsy forceps is targeted to the lesion. In the turnaround position from the stomach, some lesions cannot be accessed despite torquing or twisting.

Reducing the Number of Uninterpretable Biopsy Specimens

Independent of which forceps or technique is used, one key way to reduce the uninterpretability rate of biopsy is to have the endoscopy assistant indicate when a biopsy specimen is nearly invisible or when there is only blood or mucus. Such specimens should be discarded. In the process of taking biopsy specimens in our unit, the endoscopy assistant calls out whether a specimen is adequate or otherwise. Apart from size, superficial shallow specimens can be identified by the endoscopy assistant as translucent. Even the most experienced “biopsy veterans” have to go back every five or six biopsies. Unless endoscopists look at the biopsy specimens with the pathologist, they never know how many specimens of a group are interpretable. Histologic diagnoses are sometimes made by piecing together several uninterpretable fragments in the “mind’s eye.”

Minimizing Biopsy Surveillance Antipathy and Biopsy Exhaustion or Boredom

It is likely nearly impossible to reach a state of “joy of biopsy” even when the reason for the endoscopy is tissue-is-the-issue. Examples include surveillance for dysplasia and cancer in ulcerative colitis and Barrett’s esophagus. Part of the antipathy to surveillance biopsies is that the “drudgery effect” is eagerly passed on to fellows from one generation to the next by the endoscopy attending physicians.

When multiple biopsies are required, it helps enormously to have a second assistant in the room to operate the forceps and handle the tissue while the other assistant monitors the patient. For upper endoscopic procedures such as Barrett’s esophagus surveillance, a well-sedated patient who does not keep bolting upright helps. The use of an anticholinergic before the procedure may reduce saliva and gastrointestinal secretions, and is routine in some practices.

Transferring Biopsy Specimens from Forceps to Fixative

The best way to remove biopsy specimens from the forceps is to use a blunt probe to push the specimen out from the base of the opened forceps cups. If one pushes the specimen out by pressing it from the top of the opened forceps or picking at it, the specimen becomes squashed.

Shaking biopsy specimens off the forceps into a fixative bottle may traumatize the tissue and cause denudation of the epithelium, especially from the gastric body. Endoscopists who use the shake technique should alert the pathologist to look for detached epithelium in biopsy specimens from different parts of the gastrointestinal (GI) tract and give feedback. Most pathologists are so used to seeing detached epithelium that they assume it is a default feature (norm) from the trauma of the scope or the forceps.

When exudative lesions are biopsied for diagnosis, shaking specimens into the fixative may peel off the exudate that contains the evidence for the presence of organisms, especially Candida and herpes simplex. These organisms reside in the surface exudate or epithelial slough. Cytomegalovirus does not, and it requires biopsy for diagnosis.

Orientation of biopsy specimens on support materials in the endoscopy unit is not required in clinical practice and in inexperienced hands may lead to more tissue trauma. The key to having well-oriented, high-quality biopsy specimens for histologic examination rests with the pathology histotechnologist’s ability and motivation to embed the tissue “on its edge” in paraffin and obtain sections through the central core of the specimens.⁶ That depends on providing the histotechnologist with specimens of adequate size.

Number of Biopsy Specimens in a Fixative Bottle

Most histotechnologists cannot line up more than four biopsy specimens in a tissue block during embedding and section them so that all are represented in optimal orientation for interpretation (Fig. 5.4). Endoscopists claim that they put 10 or more specimens in a single bottle to reduce the costs. They do not usually get feedback, however, and if they did, they would learn that only half or less of those 10 specimens may be fully interpretable (see Fig. 5.4). In one regional community pathology laboratory, the pathologists separate the biopsy specimens themselves for embedding at four or five per cassette.

Fig. 5.4 Too many biopsy specimens placed into one fixative bottle and in one tissue block. Fragments of variable sizes cannot be positioned en bloc, and each biopsy specimen is not oriented. Dark lines represent tissue wrinkling in sectioning. The hallmark of grossly misoriented biopsy specimens is shown at the bottom as cross-sectioned circles (“doughnut effect”) with no clue as to the real architecture.

Polyps: Identifying the Stalk Region

When snare polypectomy is used for the removal of pedunculated or sessile polyps, the key part of the specimen for cancer diagnosis is in the stalk region or the base in the case of sessile polyps (Fig. 5.5). Stalks retract right after removal of the polyp and often shrink further and disappear after fixation. The best way to identify the stalk is to impale it with a short (1-inch) 25-gauge needle, right to the hub with the needle point emerging at the most convex part of the tip of the polyp (see Fig. 5.5). An alternative is to ink the polyp stalk after removal. After fixation for a few hours, the polyp is bisected with a scalpel or razor blade in the pathology laboratory. The two bisected halves are embedded facedown, and this way the first sections to come off are those that show the stalk region in its best orientation.⁶ Larger specimens should go right to the pathology laboratory to be assessed as gross specimens.

Fig. 5.5 Polypectomy, first preinked. The base of the polyp has a needle inserted through to the tip of the polyp. In the laboratory, the polyp is bisected along the needle path, and the central halves of the polyp are embedded facedown so that the base or stalk zone is represented in the first sections to be collected.

Small Polyps

Small polyps may be retrieved into a suction trap; this does not seem to damage the tissue. One key to using a suction trap without getting the polyp stuck in the suction channel is to have the polyp in a pool of liquid before suctioning. If there is no liquid, saline can be instilled first.

Shave Biopsy

Shave biopsy of larger polyps is to be shunned. The diagnosis of cancer or its exclusion requires that the muscularis mucosae and upper submucosa be visualized. If multiple fragments are submitted with no orientation, the pathologist often cannot provide reassurance that invasion is not present. If there is no choice but to submit two or three pieces of the lesion, each should be marked with ink to show the cut side. This marking permits the pathologist to know where the submucosa is located if present in the specimen. The removal of large specimens requires the same principles that surgeons use in resections.