Performing and Processing FNA of Anterior Fat Pad for Amyloid

This video demonstrates fine needle aspiration, biopsy of the anterior fat pad, and a procedure for processing the biopsy specimens for microscopy. The skin in the lower quadrant area of the abdomen lateral to the midline and below the umbilicus is cleaned and a rhomboid shaped area is designated with a marking pen. The local area is anesthetized and a biopsy of the anterior fat pad is performed by fine needle aspiration.

Five to six fragments of the fibro adipose tissue are transferred from the biopsy syringe into glutaraldehyde solution, and the remaining material is allowed to clot in the syringe. 10%formalin is aspirated into the syringe and the plunger is removed to transfer the clotted fibroadipose tissue into 10%formalin. Hi, I'm Dr.Ham from Department of Pathology at Medical College of Wisconsin Milwaukee.

I am Dr.Parri. I'm from the division of Neoplastic Disorder and related Diseases at Medical College of Wisconsin. Today we are demonstrating a procedure how to perform a fine needle aspiration biopsy for fat pad, aspiration for studying AMY amyloidosis.

This is a protocol that we use for sampling fibroadipose tissue from the anterior abdominal fat for demonstration and ruling out amyloidosis. So let's get started. When properly performed the fine needle aspiration biopsy or FNAB procedure for anterior fat pad aspiration can be completed in one prick.

However, maneuvering an 18 gauge needle back and forth in the subcutaneous fat tissue is relatively distressing. The anesthetization method described here achieves the effect in only two pricks with a 25 gauge needle and diverts pain resulting in improved tolerance to the procedure. Prepare for the procedure by gathering all of the materials needed, including a one to one mixture of 1%lidocaine and 1%sodium bicarbonates alcohol swabs, gauze pads, a marking pen, two 10 milliliter syringes, two 18 gauge, one and a half inch needles, a 25 gauge, one and a half inch needle, an FNA syringe holder or gun, a bandage, a vial of glutaraldehyde for electron microscopy, and a biopsy container of 10%Four.

Using alcohol swabs, clean the skin on the lower quadrant area of the abdomen, lateral to the midline and below the umbilicus marker. Roid shaped area about two by two inches with a marking pen. Using an 18 gauge needle and a 10 milliliter syringe aspirate approximately 10 milliliters of the 1%lidocaine, 1%sodium bicarbonate solution to use as a local anesthetic.

Although 1%lidocaine may be used alone, the added sodium bicarbonate will prevent the initial brief burning sensation. After installation, detach the lidocaine filled syringe from the 18 gauge needle still in the lidocaine vial. Attach the syringe with a 25 gauge one and a half inch needle holding the syringe upright.

Press the plunger and tap the syringe barrel to remove any trapped air from the syringe anesthetize along the borders of the roid area. Start by inserting the 25 gauge needle just under the skin at point A.Then carefully push the needle subcutaneously and tangentially parallel to the overlying skin surface towards point X.At point x. Pull back on the syringe plunger to ensure that the needle is not within a vessel.

Then while withdrawing the needle to point a slowly push the plunger to infiltrate up to 2.5 milliliters of lidocaine. Do not allow the needle to come out of the skin. Now change the direction and push the needle subcutaneously to point Y.As before, confirm that the needle is not in a vessel by pulling back on the syringe plunger and dispense up to 2.5 milliliters of lidocaine while slowly withdrawing the needle through Point A after withdrawing the needle, prevent bleeding by firmly applying sterile gauze.

Next, starting from point B, repeat this process dispensing lidocaine subcutaneously from point X to point B.Then from point B to point Y.Again, apply gauze to prevent bleeding. Now, check that the area is anesthetized by lightly touching the skin within the rhomboid with the corner of a cotton gore's piece and comparing it with the adjacent un anesthetized skin. Attach an 18 gauge one and a half inch needle to a 10 milliliter syringe.

Mount the syringe needle assembly in the syringe grip FNAB grip gun to assist in proper application and release of vacuum. Insert the tip of the needle into the subcutaneous fat within the cleansed and anesthetized rhomboid area, and fully retract the plunger of the syringe to generate vacuum. Maintaining the vacuum maneuver the needle back and forth within the subcutaneous fat.

Each stroke should be as long as possible without letting the needle come out of the skin. Maximum sampling is achieved by changing direction with each stroke. It's important to keep the direction of the needle tangential to the serosa and parallel to the skin surface to avoid puncturing of the peritoneal cavity.

Once approximately one milliliter of fibroadipose tissue fragments has accumulated in the syringe, release the vacuum and remove the needle. Have the patient apply firm pressure on the area of procedure with a pad of gauze to minimize subcutaneous excavation of blood. The specimen can now be processed for submitting to the laboratory.

For further testing, remove the syringe needle and transfer five to six fragments of fiber adipose tissue into 2%glutaraldehyde solution through the nozzle of the syringe. Dispense additional small fragments of tissue through the nozzle of the syringe onto a glass slide spread between two slides. To prepare smears, allow the remaining material to clot in the syringe.

This may take five to seven minutes. Next, aspirate 10%formalin in the syringe so that the clotted fibro adipose tissue material is dislodged from the wall of the syringe and free floating. Now, remove the plunger from the syringe and transfer the clotted fibro adipose tissue into the labeled 10%formula in container from the open end of the syringe opposite the nozzle end.

The collected samples can now be submitted for electron microscopy, cell block preparation and paraffin embedding or fluorescent microscopy, fibro adipose tissue obtained and formal and processed using the method Shown in this video was paraffin embedded stained with Congo red and examined by polarizing light microscopy. Amyloid in the wall of small blood vessels in the fibro adipose tissue. Fragments show apple green by ence as indicated by the yellow arrow.

The apple green by ence is absent in tissues from a different patient without amyloidosis. Blue by ence indicated by the yellow arrow head of collagen fibers are usually present in almost all specimens. In our experience, this collagen related blue birefringence may be difficult to differentiate from apple green birefringence of amyloid.

This is a significant pitfall during the interpretation of Congo. Red stain specimens under polarizing microscope. This electron micrograph shows straight non branching, randomly scattered eight to 10 nano micron diameter fibrile consistent with amyloid in a blood vessel wall.

So we just demonstrated you how to perform fin needle aspiration, biopsy of anterior fat pad for amyloid. When doing this and other similar FNAB procedures, it's very important to apply and release the vacuum in proper sequence. Also, for very obvious fear of entering the peritoneal cavity, the needle should never be directed obliquely.

Therefore, it's important to maintain the direction of the back and forth strokes parallel to the skin in the subcutaneous plane of the fibrous tissue. These are very important points. So that's it.

Thanks for watching. Thank you.