Biopsies Flashcards
Biopsy
Biopsy is the surgical removal of a tissue specimen from a living organism for microscopic examination and final diagnosis.
A biopsy is a minor surgical procedure and, depending on whether the entire pathologic lesion or part of it is removed, is either an excisional biopsy or incisional biopsy.
Principles for Successful Outcome of Biopsy
• In clinically suspicious lesions, biopsy must be carried out as soon as possible.
• The choice of the biopsy technique to be employed is determined by the indications of each case.
. The tissue specimen taken should be representative.
• Immediately after its removal, the tissue specimen should be placed in a container with fixative.
• Keeping the tissue specimen outside of the container for a prolonged period dries the specimen, while there is a risk of it falling or being misplaced.
• The fixative solution to be used is 10% formalin, and not water, alcohol, or other liquids that destroy the tissues.
• It is recommended that the container to be sent to the laboratory is plastic to avoid risk of breakage during its transfer and subsequent loss of the specimen.
• The label with the name of the patient and date should be placed on the side of the container, and not on the lid.
• This way the possibility of mix-up at the laboratory after opening is avoided.
Instruments and Materials
The materials considered necessary for biopsy are: local anesthetic cartridge and needle for anesthesia, sutures, surgical dressing, gauze, and vial containing 10% formalin solution for placement of specimen.
As for aspiration biopsy, the necessary instruments and materials include the following:
- trocar needle or a simple low gauge needle
- plastic disposable syringe
- glass slides
- fixative material.
EXCISIONAL BIOPSY
This technique entails removal of the entire lesion, along with a border of normal tissues surrounding the lesion.
The indications for employing excisional biopsy are the following:
- Small lesions, whose size ranges from a few millimetres to one or two
centimetres. - Specific clinical indications that the lesion is benign.
- The surgical procedure may be performed at the dental clinic with the usual armamentarium
- The surgical procedure may be performed if the operation is within the scope of the general practitioner
Procedure for performing the excisional biopsy
• Administration of local anesthesia , which is performed at the periphery of the lesion and not directly inside the lesion
• Two elliptical incisions are made on normal tissue surrounding the lesion, which are joined at an acute angle.
• The lesion is then removed
• The mucosa is undermined using blunt scissors
• The wound margins are re-approximated and suturing is performed
• Healing is achieved by primary intention
EXAMPLES OF LESIONS THAT MAY BE REMOVED WITH EXCISIONAL BIOPSY FROM DIFFERENT INTRAORAL SITES
TRAUMATIC FIBROMA
PERIPHERAL GIANT CELL GRANULOMA
HEMANGIOMA
PERIPHERAL FIBROMA OF GINGIVA
LEUKOPLAKIA
EXAMPLES OF LESIONS THAT MAY BE REMOVED WITH EXCISIONAL BIOPSY FROM DIFFERENT INTRAORAL SITES
TRAUMATIC FIBROMA
PERIPHERAL GIANT CELL GRANULOMA
HEMANGIOMA
PERIPHERAL FIBROMA OF GINGIVA
LEUKOPLAKIA
INCISIONAL BIOPSY
Incisional biopsy involves removal of only a portion of a relatively more extensive lesion, so that histopathological examination may be performed and a diagnosis made.
• It is indicated in cases where the lesion is larger than 1 or 2cm and when there is suspicion that the lesion is malignant.
• With incisional biopsy, besides diagnosis, other characteristics of the neoplasm are defined as well, such as differentiation, invasiveness
The incisional biopsy technique involves the following:
• Local anesthesia
• Wedge-shaped portion of the most representative part of the lesion is removed
• Usually from the periphery of the lesion and
• Extending into normal tissue as well
• When the lesion is located in deeper tissues, surgical access is accomplished after an incision on the mucosa.
ASPIRATION BIOPSY
• Aspiration biopsy is indicated in cases where lesions are not accessible for histopathological examination, e.g., tumors of the parotid gland, lymph nodes, cysts
• It is performed using a trocar needle or fine needle (21-gauge to 23-gauge) adapted to a glass syringe or plastic disposable syringe
• The aspirated material is smeared on a glass slide and immersed in Hoffman solution (95% ethyl alcohol solution and 5% ether solution) in equal parts or it is fixed with hair spray.
• Cytological examination is performed.
• A histological examination may be performed if a specimen is sucked into the needle tip, usually with a trocar needle, and expressed onto a glass slide.
SPECIMEN CARE
• The tissue specimen removed with biopsy is placed in a vial containing an aqueous solution of 10% formalin (4% formaldehyde) and sent to the laboratory, along with the biopsy data sheet containing all the necessary clinical information.
• The pathology laboratory will send the dentist the pathology report that includes a histological description and diagnosis
EXFOLIATIVE CYTOLOGY
• This method is to be used as an additional aid to, and not a substitute for, biopsy, mainly providing bacteriological information.
• The reason for this is that it is considered unreliable due to lack of pathologist expertise in the field of exfoliative cytology.
• Individual cells are examined, rather than the lesion as a whole, which represents a drawback.
• The lesion is scraped using a cement spatula or tongue depressor.
• The superficial cells scraped from the area are smeared evenly on a glass slide.
• The fixation procedure that follows is the same as that for aspiration biopsy, after which the cells are stained.
TOLOUIDINE BLUE STAINING
• This method is used most often to indicate the most appropriate biopsy location, even though it does not indicate tumors present under normal epithelium.
• A 1% tolouidine blue staining solution is applied to the epithelial surface, whereupon rinsing with a 1% acetic acid solution leaves no stain on normal epithelial surfaces or benign erythematous lesions.
• On the contrary, the stain remains on the surface of premalignant and malignant erythematous lesions.
• Benign lesions usually have well-defined stain margins, whereas premalignant or malignant lesions have more diffuse margins.
