Oral biopsy definition,types and procedure

What is an Oral Biopsy?

Oral Biopsy is a surgical procedure to obtain tissue from the patient’s oral cavity, for microscopic examination, usually to perform a diagnosis.

A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disease.

The French dermatologist Ernest Besnier introduced the word biopsie to the medical community in 1879

The term biopsy reflects the Greek words, "life," and, "a sight." Vision of life

A tissue sample can be taken from almost anywhere on or in your body, including the skin, organs and other structures.

The term biopsy is often used to refer to both the act of taking the sample and the tissue sample itself.

When we need a biopsy ?

A biopsy can be used to investigate abnormalities, which can be:

functional – such as kidney or liver problems

structural – such as swelling in a particular organ

When the tissue sample is examined under the microscope, abnormal cells may be identified, which can help to diagnose a specific condition.

An Oral Biopsy can be performed for several reasons. Sometimes:

If there are inflammatory changes in the oral cavity of unknown cause that persist for long periods;

an oral lesion interferes with proper oral function;

for bone lesions that are not specifically identified by clinical examination and X-rays, or any oral lesion that has the characteristics of a malignancy.

If a condition has already been diagnosed, a biopsy can also be used to assess its severity (such as the degree of inflammation) and grade (such as the aggressiveness of a cancer).

Examples of conditions where a biopsy may be helpful include:

cancer

inflammation, such as in the liver (hepatitis) or kidney (nephritis)

infection, such as in lymph nodes – for example, tuberculosis

various skin conditions

It's not usually possible to tell whether a lump or growth on your skin or inside your body is cancerous (malignant) or non-cancerous (benign) by clinical examination alone, which is why a biopsy is often required.

Types of biopsy

Depending on the characteristics of the target lesion, the biopsy is defined as direct (located superficially, with easy access) or indirect (when the lesion lies in depth and is covered by normally appearing mucosa or tissue) . However, biopsies can also be classified according to the technique used, the material employed, the clinical timing, the location of the target lesion, processing of the sample, and the purpose of the biopsy.

1) The technique employed:

. The incisional technique

Such an approach is indicated in the case of suspected malignancy or precancerous lesions. Likewise, such a multiple sample biopsy should be performed when the target lesion is difficult to remove due to its large size or complicated location. It is also indicated for establishing the diagnosis of a systemic disease process.

Controversy exists as to the possibility that incisional biopsies of malignant lesions may increase the risk of metastasis, by disrupting the barrier preventing migration of the neoplastic cells and thus favoring invasion of the bloodstream at the site of the surgical wound .

In certain tumors such as hemangioma or melanoma, the biopsy should be performed with complete and extensive resection of the lesion, in order to avoid severe bleeding or metastatic spread, respectively .

An excisional biopsy in turn involves total removal of the lesion, with slight peripheral and in-depth safety margins, applicable to papillomas, fibromas or granulomas . Such biopsies play a diagnostic and therapeutic role, since complete removal of the lesion is carried out, ensuring the inclusion of a peripheral margin of normal tissue .

2) The material used :

A number of cutting instruments can be used when performing a biopsy: a conventional scalpel, a punch, and the so-called B-forceps.

On the other hand, while the electroscalpel has the advantage of causing no bleeding, since it cauterizes the vessels, its main inconvenience is the induction of thermal damage. Although similar, the laser scalpel produces less extensive thermal damage and less postoperative pain. However, in the same way as the electroscalpel, it is currently not advised for obtaining oral biopsies.

3) Clinical timing of sampling:

Depending on the clinical timing of the biopsy, the procedure can be classified as intraoperative or extraoperative.

4) Sampling location:

Depending on the topography involved, the biopsy can be obtained from the oral mucosa in its different locations , the salivary glands, bone, lymph nodes, and other head and neck tissues. A biopsy of the oral mucosa is simple to perform, and is used to distinguish among different types of lesions, in order to define adequate treatment or conduct follow-up over time. A conventional biopsy is usually indicated

Regarding the salivary glands, it is very common and easy to obtain a biopsy of the lesser salivary glands of the lips for diagnosing or confirming an autoimmune condition such as Sjögren’s syndrome

On the other hand, when biopsying the greater salivary glands, and specifically the parotid gland, fine-needle aspiration biopsies (FNAB) are increasingly used

5) Processing of the sample:

Depending on the processing procedure involved, the sample can be analyzed frozen, or embedded in paraffin or methacrylate, and can be examined under the electron microscope, or as a fresh sample. Molecular analyses are also possible.

6) Purpose of the biopsy:

Biopsies can be performed for diagnostic or experimental purposes.

a punch biopsy – a special instrument punches a small hole in the skin to obtain a skin sample to investigate a skin condition

a needle biopsy – a special hollow needle, guided by X-ray, ultrasound, CT scan or MRI scan, is used to obtain tissue from an organ or from tissue underneath the skin

an endoscopic biopsy – an endoscope is used to remove tissue, such as from the stomach during a gastroscopy

an excision biopsy – surgery is used to remove a larger section of tissue

How a biopsy is carried out will depend on where the tissue sample is being taken from.

Before the procedure, CT or MRI scanning is often used as a guide to help with this decision.

After the tissue sample is taken, it will be examined under a microscope to help identify the nature of the problem. This often means that a definite diagnosis can be made.

The type of stains and tests that are used when the tissue is examined under the microscope will depend on the medical condition being investigated.

Punch biopsy

A punch biopsy can be used to investigate a variety of skin conditions.

During a punch biopsy, a special surgical instrument is used to make a small hole in the skin and remove samples of the top layers of tissue.

If you have a punch biopsy, you'll usually be given local anaesthetic to numb the area.

Alternatively, a scalpel (a sharp medical knife) may be used to remove a small amount of surface skin. The wound will be closed using stitches.

The oral mucosal punch is a rapid, simple, safe and inexpensive technique for obtaining a representative sample of most oral zones. The technique and usefulness are similar to those of the skin punch.

The punch is grasped between the index and thumb, supporting the cylinder over the target lesion. If a small-diameter cylinder is obtained, suturing of the residual wound is usually not necessary, and the bleeding can be contained by simply applying a piece of gauze or surgical dressing. The wound heals by second intention, with good esthetic results. In other cases, primary wound closure can be performed with sutures.

Punches are typically made of plastic or metal. The metal presentations can be reused, and are to be sterilized before use. In contrast, the plastic variants are less expensive, weigh less and are destined for single use .

The punch is able to obtain several samples at the same time, and at different points, and generates less patient anxiety than the conventional scalpel

However, the punch is unable to remove large lesions, and cannot be used in intensely vascularized or innervated areas. It is likewise not applicable to deep lesions, and is limited to epithelial or superficial mesenchymal target tissues. Caution is moreover required when using the punch to sample lesions located over important submucosal structures such as the mental or nasopalatine foramen. On the other hand, the instrument is difficult to use in the region of the soft palate, maxillary tuberosity or floor of the mouth, due to the lack of firm tissue fixation or support, and the mobility of the target zone

Needle biopsy

A fine-needle aspiration (FNA) biopsy is often used to take cell samples from organs or from lumps that are below the surface of the skin.

If a larger sample is needed, a core needle biopsy (CNB) will be used instead.

For core biopsies, after local anaesthetic has been given, a hollow needle is inserted through the skin and into the area being examined.

X-ray, ultrasound, CT or MRI scanning will often be used to help guide the needle to exactly the right place.

When the needle is in position, it'll cut out a small sample of tissue. For core biopsies, local anaesthetic is usually used to numb the area, so you won't experience any pain or discomfort.

A core needle biopsy (CNB) is often used to obtain a larger tissue sample. In some cases, when a cyst (a benign fluid-filled swelling) is suspected, a fine needle will be used to drain the fluid and the cells are sent for examination (cytology).

Types of Oral Biopsy

There are six main types of Oral Biopsy. These are:

Cytology: This type of Oral Biopsy can be used to diagnose lesions in the oral cavity due to post-radiation changes, herpes, and fungal infections. Cytology allows examination of individual cells but cannot necessarily result in an accurate and definitive diagnosis. It is recommended that this type of Oral Biopsy be performed along with an Excisional or Incisional Biopsy.

Aspiration Biopsy: In this type of Oral Biopsy, the oral surgeon uses a needle and syringe to remove a sample of cells or contents of a lesion. If the oral surgeon is not able to withdraw fluid or air it probably means that the lesion is solid.

Incisional Biopsy: This type of Oral Biopsy is performed only to sample a representative portion of the oral lesion. If the lesion is large or has many differing characteristics, it may require sampling of more than one area.

Punch Biopsy: This is done with a punch tool for both incisional and excisional purposes. This type of Oral Biopsy is best suited for the diagnosis of oral manifestations of mucocutaneous and ulcerative conditions of the oral cavity, such as lichen planus.

Brush Biopsy: In this type of Oral Biopsy, firm pressure with a circular brush is applied, and rotated give to ten times, causing light abrasion. The cellular material picked up by the brush is transferred to a glass slide, preserved and dried.

Excisional Biopsy: This type of Oral Biopsy is performed for small oral lesions, usually less than 1 cm. On clinical exam, the lesion appears benign. This type of Oral Biopsy results in complete removal of the lesion.

How to perform an oral biopsy ?

Prior to performing an Oral Biopsy, the oral and maxillofacial surgeon should be fully aware of the patient’s medical status. This would involve a thorough review of the patient’s medical and dental history, including previous surgeries, medications, allergies, and any social behaviors, such as smoking, alcohol use, and illicit drug use. The oral surgeon should also perform a thorough clinical and radiographic exam.

An Oral Biopsy is usually performed under either a local anesthetic, applied locally with infiltration near the lesion, or then, regionally, with a nerve block technique. However, the anesthetic should not be applied directly into the lesion, or superficially in and around the lesion, as this may result in a false diagnosis by the oral pathologist.

Once the local anesthetic is applied, the oral surgeon should firmly retract the soft tissues surrounding the lesion, and should make an elliptical incision around the lesion, with a minimum of a 1 mm margin.

Once the lesion has been freed from the remaining soft tissues, it should be immediately placed into a sterile pathology specimen jar, containing 10% buffered formalin for fixation. The container must be labelled with accurate patient information, such as patient name, birthdate, date, and site of biopsy.

After the Oral Biopsy, firm manual pressure should be applied to the biopsy area to stem any bleeding. Finally, the incision should be closed using either resorbable or non-resorbable sutures. Sterile gauze should again be applied to the surgical site to assist with blood clotting and to prevent the swallowing of blood by the patient.

Due to the slight oozing of blood from the surgical site for about 24 hours, the patient should be provided with a packet of gauze to change every 20 to 30 minutes over the course of a day. The gauze should not be kept in the mouth overnight.

The materials and instrumentation required to perform an oral biopsy are simple . The necessary instruments are buccal mirror, probe, toothless dissection forceps, mosquito forceps, scalpel handpiece and number 15 blade, syringe for anesthesia, pressure forceps, scissors, periostotome, separators, needle holder and suture .

Most target lesions are found in soft tissues such as the tongue, cheek mucosa or lips, or in more adhered regions such as the palate and gums. Anaesthesia with a vasoconstrictor to minimize bleeding should not be applied in the actual biopsy target zone but rather at a certain distance 3-4mm, to avoid alterations.

Traction suture or tissue forceps are to be used to fix the tissue to be removed. Traction sutures offer the advantage of orienting at least one lesion surface for the pathologist. Surgery is moreover facilitated, and compression or destruction of the specimen (as tends to occur when using puncture or cutting instruments) is avoided .

The specimen should be obtained by means of a clean and deep cut, taking care in extraction to avoid tearing or compression, as this could cause alterations. In excisional biopsies, the lesion is to be palpated carefully, determining its depth, and the incisions should slightly exceed the total depth of the lesion. In incisional biopsies, any depth within the lesion allowing the obtainment of sufficient material for study is considered acceptable. The incision should include a significant portion of the suspect tissue, though also a part of adjacent normal tissue .

The wound margins are subjected to debridement, with control of bleeding, and the lips of the wound are joined with suture. When a sample of gingival tissue or palate is obtained, and closure of the incision proves difficult, it can be left to heal by second intention. Oxidized and regenerated cellulose can be applied, together with gauze impregnated with tranexamic acid, to avoid bleeding .

After obtaining the sample, washing with physiological saline is indicated, followed by fixation. Sample processing begins once the specimen has been obtained, with the purpose of allowing tissue study under magnification. The steps comprise fixation, cutting into fragments or blocks, embedding, sectioning, staining and examination. The most common procedure is staining with hematoxylin-eosin, followed by examination under the light microscope .

Light microscopic studies generally involve the use of 10% formaldehyde solution in water; the concentration must be sufficient to ensure correct fixation of the tissue.

On the other hand, for electron microscopic preparations, the specimen is immersed in 3% glutaraldehyde in the refrigerator for 24 hours, followed by transfer to a 0.1 M buffer solution until study .

Testing the tissue sample

After a tissue sample has been taken, it'll be sent to a laboratory to be examined under a microscope.

Closely examining the cells in the tissue sample enables histologists (doctors who specialise in studying the structure of tissues) to determine whether they're normal or abnormal.

For instance, cancerous cells look and behave differently from normal cells.

As well as looking at the tissue sample, chemical or genetic tests may also be carried out, if needed.

In cystic fibrosis, for example, a chemical test can be used to help diagnose the condition.

Contraindications

On the other hand, a biopsy is contraindicated in very seriously ill patients, in those subjects with some systemic disorder that may worsen, or where secondary complications may develop

Likewise, a biopsy should be avoided in the case of lesions located in very deep regions or in areas of difficult access where the surgical technique proves complicated or hazardous, with the risk of damage to neighboring structures.

Biopsy is not advised in the case of multiple neurofibromas, due to the risk of neurosarcomatous transformation, or in tumors of the greater salivary glands.

Biopsy complications

Bleeding may occur in the first 24 hours after the procedure, as a result of clot disruption during the early healing period, or secondary to suture loosening. Minor bleeding responds to local pressure application, while more important bleeding requires ligation, cauterization or the closure of some bleeding point

Dehiscences are infrequent, however. Such problems may develop 5-8 days after biopsy. The implicated local factors comprise bleeding, infection, excess suture material or excessively tightened sutures that tend to strangle local vascularization

On the other hand, infection is also rare and is attributable to a deficient surgical technique. Treatment in such situations consists of drainage of the infectious material, and antibiotic medication.

Another possible complication of oral biopsies is sensory impairment. This type of problem may result from a defective surgical technique, and can be avoided. Sensory defects are secondary to sensory nerve damage during the biopsy procedure.

The specimens obtained with oral biopsy procedures are typically small, and the risk of artifacts is considerable. These artifacts, which are sometimes seen under the microscope, may pose a problem for establishing a correct histopathological diagnosis.

Oral biopsy definition,types and procedure