Ultrasound-guided needle biopsy in children

General

Ultrasound-guided biopsy is sometimes used to diagnose possible pathology in suspect lesions/changes. Fine-needle biopsy is always used initially. The cell smear is immediately stained and assessed by a cytologist. In most cases, a histological pistol biopsy is also performed (Tru-Cut®). It is often necessary to wait 2-6 days for the result before starting treatment. 

Indication

• Ambiguous lesions detected with radiological testing.

Goal

• Confirm or rule out malignant histology of suspect lesions.

Equipment

Biopsy equipment    

 

Preparation

• For ultrasound-guided puncture under general anesthesia, the child must fast for the last 4-6 hours before the test.
• Depending on the localization and accessibility of the lesion, precautions should be taken regarding bleeding parameters (hemoglobin, thrombocytes, INR, and Cephotest).
• The child and parents are informed about the procedure.
• The biopsy is performed under general anesthesia.

Implementation

Ultrasound-guided biopsy is performed under general and local anesthesia depending on the depth and localization.

• Localize the lesion with the ultrasound probe.
• Determine the best point and direction for puncture.
• Mark the puncture point so the canal is easy to remove later.
• Wash the puncture point with colored chlorhexidine 1 mg/ml.
• Allow the skin to dry.
• Inject local anesthesia if necessary.
• Puncture the spinal needle quickly through the skin.
• Guide the needle through the peritoneum using ultrasound and further into the lesion.
• Remove the stylet.
• Aspirate. 
• When the material is visible at the top, the needle is retracted.
• Deposit the material on a slide.

Smear for cytology

• Smear the material on to the slide.
• Allow the material to air dry.
• Staining: fixing fluid with methanol + Hemacolor + rinsing in water
  • 5 dips in fixing fluid. Allow the solution to drop onto paper. 
  • 3 dips in staining solution 1.
  • 6 dips in staining solution 2. Allow the solution to drop onto paper.
  • Rinse in 2 baths of clean water.
• Examine the specimen under the microscope with 10x or 20x objective.

The microscopic assessment of the cell material should be performed by a cytologist to determine if there is adequate tissue or if there should be supplementary testing.

Histological biopsy (pistol biopsy)

• Inject the local anesthesia in the skin.
• Make a small incision in the skin.
• Insert the biopsy needle on to the lesion and gently into it, depending on the size of the lesion and the type of tissue in front and behind the lesion.
• Trigger the pistol to retrieve the material.
• Retract the needle and open it. 
• Place the piece of tissue onto a slide with medium, for example formalin or 0.9% NaCl.

Follow-up

• The child will often remain in the hospital until the following day.
• Depending on the location of the biopsy, bleeding can sometimes occur after taking the specimen.
• For pain or bleeding, the patient must be observed at the ward or intensive unit depending on the severity. Necessary measures must be initiated.
• After a biopsy of parenchymatous organs, an ultrasound examination is made, and hemoglobin is checked possibly the following day.