Biopsy Techniques and Mass Removal
Fine needle aspirate
20 or 22 gauge needle 5-12 cc syringe Insert needle into mass Aspirate
Abdominocentesis
Also called abdominal paracentesis Purpose is to obtain sample of peritoneal effusion Equipment: 1 inch, 22g needle IV extension tubing 6 cc syringe Surgical scrub
Excisional biopsy
Also referred to as surgical biopsy Involves removal of the entire mass and often times serves as treatment Cut "Early, Deep, and Wide"
Needle Punch Biopsy
Area is clipped and aseptically prepped Area skin and muscle is blocked with a local anesthetic Small stab incision is made over area to be biopsied End of needle is inserted into stab incision & instrument is fired advancing the inner needle into the mass
Punch Biopsy
Area to be biopsied is clipped and aseptically prepped Ask whether DVM prefers alcohol or chlorhexidine scrub for prep Local anesthesia is injected SQ and given 3-5 minutes to take effect General anesthesia usually needed for nasal region or foot pads
Transtracheal Lavage
Aspirate repeatedly from the catheter With each aspirate, disconnect the syringe and release the air before beginning aspirate again Repeat procedure with the other ½ saline Monitor patient for signs of respiratory distress 1 hour post procedure
CSF Collection
Cerebral Spinal Fluid Collection Locations: Cerebellomedullary cistern and lumbar cistern Purpose is to collect CSF for laboratory tests, measure CSF pressure, or access the subarachnoid space for myelography Equipment 20-22 g needle with 1 ½ - 2 ½ spinal needle with stylet Manometer with 3-way stopcock Sterile scrub
Sample Handling
Containers must be labeled! --Date, Time, Patient's name, location of sample History and signalment are vital --Clinical findings and lab work should be provided Provide tentative diagnosis
CSF Collection
Drape area with sterile drapes DVM will locate area to puncture by intersecting imaginary lines crossing wings of the atlas and external occipital protuberance Stylet is advanced and routinely checked for presence of CSF
Impression Smears
Easy to perform and requires no sedation Allows for cytological evaluation; Can be stained and read in-house. Performed on ulcerated surfaces of tumors as well as freshly cut surfaces. Surface of the mass should be blotted to remove excess blood or debris.
Sample Handling
Excisional samples can be "painted" prior to fixing in formalin so pathologist can determine if margins are "clean" India ink Alcian blue
Transtracheal Lavage
Find cricothyroid ligament using your index finger. The ligament is between the thyroid cartilage and the cricoid cartilage and palpates semi-soft along the ventral surface of the larynx Clip and scrub the area Line block with lidocaine (0.25-0.5 ml)
Histopathology
If multiple samples, use multiple jars each with full ID on label, including location (Biopsy diagrams) Requisition form - fill out completely and be detailed --Histo labs deal with thousands of samples so it's crucial to have all patient, owner, clinic information completed --Description of mass is needed for correct DX ----Size, shape, color, texture, duration, signalment
Histopathology
Important to paint margins so pathologist can orient the tumor and check for clean vs dirty margins Surgeon can drop sample into an open jar you are holding - stay away from living tissue in case of splashing Or, sample can be handed off - wear exam gloves. Asepsis is not necessary
Transtracheal Lavage
Insert catheter bevel side down through the cricothyroid ligament and into the trachea Use caution don't want to lacerate the dorsal aspect of the trachea Thread the catheter into the trachea while stabilizing the catheter at the same time
Transtracheal Lavage- Complication
Laceration of trachea or larynx Pulmonary aspiration of catheter Pneumothorax Respiratory distress
Trephine
Larger smaple and greater diagnostic yield, but increases risk of fracture.
Bone biopsy needle
Less invasive but smaller sample size.
Histopathology
Losing a biopsy sample is malpractice. Pay careful attention Preparation of sample for pathologist will greatly enable an accurate diagnosis Formalin is 10% Formaldehyde. It "freezes" tissues and preserves architecture; It's also dangerous to living tissue.
Needle Punch Biopsy
Minimally invasive; performed under sedation Commercial "needle punch biopsy "instrument used to obtain small piece of tissue Sent for histopathology (not cytology) Relative large size of sample allows for better DX and staging Can be used on many different organs in addition to dermal masses
CSF Collection
Once fluid appears, attach manometer Record CSF pressure
Bone Biopsy
Painful! Requires general anesthesia Two methods
CSF Spinal Collection
Prepare patient under general anesthesia Patient is placed in lateral recumbency - which side determined by DVM's dominant hand Clip the dorsal cranial cervical spine from external occipital protuberance to below the wings of the atlas Position patient so cervical spine is place along the edge of the table
Thoracocentesis - Complications
Pulmonary lacerations -Pleural hemorrhage -Pulmonary hemorrhage -Pneumothorax Myocardial puncture -Hemorrhage -Arrhythmia
Punch Biopsy
Punch tool is rotated in one direction over mass with moderate downward pressure until punch is pushed to the base into the mass or lesion Punch tool is removed with a twisting action Scissors can be used to snip any tissue still attached to the mass. Sample is placed in a tissue cartridge or mounted on a piece of cardboard before being placed in formalin
Transtracheal Lavage
Purpose is to collect a sterile sample of fluid and/or cells from the trachea Equipment: Through-the-needle catheter 12 cc syringe Saline 0.12 ml/kg of body weight Sterile scrub Possibly endoscope
Thoracocentesis
Purpose is to obtain sample of thoracic fluid for analysis Equipment: 3 - way stopcock 12, 20, or 60 cc syringe IV extension tubing (butterfly cath for cats) 1 inch, 22 g needle Sterile scrub
Punch Biopsy
Quick, easy and relatively non-invasive and a-traumatic Performed under general or local anesthesia Doesn't penetrate deeply but provides a large surface sample Used for skin or oral masses Disposable punch biopsy tools are available in sizes that can be cold-sterilized and reused a few times
Fine needle aspirate
Simplest method of cytology evaluation of a mass. Easy to perform, no sedation needed, low cost Low diagnostic yield- small needle into large mass - may miss neoplastic cells if you inject into area where normal cells are located ...lab will report "inconclusive" findings
Thoracocentesis
Sternal recumbency is often the most comfortable position for these patients Clip and scrub site Prefer to enter at 7th or 8thintercostal space Insert needle into patient along the cranial aspect of the rib Aspirate as you enter the thorax to create negative pressure
Abdominocentesis
Submit or do in-house evaluation of fluid for cytology and/or culture & sensitivity Complications include laceration of abdominal intestines or organs
Histopathology
Take great care not to spill formalin; ESPECIALLY on living tissue In general formalin can only penetrate 1 cm into tissue samples --Maximum 2 cm wide --Larger masses should be sliced into (but not through) to allow for greater surface area for formalin penetration
Needle Punch Biopsy
The instrument is withdrawn from the pet revealing a tubular section of tissue Specimen is gently removed from sample chamber with cotton swab or needle to avoid crushing injury to the cells of the sample Sample placed in 10% formalin container and sent to lab
Incisional Biopsy
This is removing a wedge section from a larger tumor or mass Usually used with tumors located deep within the body Fixed in 10% formalin and sent to lab for histopathology
Impression Smears
Touch the surface of the mass or ulcerated area with a glass slide Do not press too firmly or may damage cells causing artifacts
Bone Biopsy Two Methods:
Trephine Bone biospy needle
CSF Collection
Unsuccessful collection Hemmorrhage Herniation of brain Puncture of medulla Infection
Sample Handling
Vital that samples are handled gently! Cellular damage can lead to great difficulty in obtaining an accurate diagnosis Detailed history and signalment is crucial Fixative choice is 10% formalin at 10 parts formalin to 1 part tissue Formalin only penetrates 1 cm so samples should be at most 2 cm thick. Larger samples can be sliced like a loaf
Thoracocentesis
When syringe is full, close the stopcock Empty the syringe, saving a sample for the lab Repeat until no more fluid or air can be evacuated Be sure to count the volume of air or fluid collected
Fine needle aspirate
Withdraw needle from mass & remove syringe from needle hub Fill syringe with air then reattach syringe to needle hub. Push air out of syringe resulting in fluid & cells from mass being evacuated onto a microscope slide. Make smear of contents After smear is dry, slide may be stained for in-house reading or sent out to a lab for histopathology
Transtracheal Lavage
Withdraw the needle of the catheter and place cover guard Attach the syringe with saline to the catheter end Flush half the saline into the catheter quickly Reattach a dry (empty) syringe to the catheter end
Biopsy
are performed to determine the cause of the lesion, the presence of cancer cells, establish tumor grading, and provide more information for treatment
Biopsy
is a diagnostic procedure in which a piece of tissue and/or cells are removed to be examined under a microscope by a pathologist, or in-house by a veterinarian.
