Ultrasound-guided fine-needle aspiration and biopsy from the pelvisMedical editor Gunnar B. Kristensen MD
Oslo University Hospital
MRI or CT is often used to assess possible spreading of different cancer types. A cytological or histological assessment of a tumor is often needed. If the lesion can be seen by vaginal ultrasound, ultrasound-guided biopsy is the optimal method for this. For localized tumor, for example a well-limited ovarian tumor without sign of spreading, the risk for spread in connection with the biopsy procedure must be taken into consideration. For probable stage I ovarian cancer, biopsy is generally contraindicated due to the risk of spread. For suspicion of sarcoma, the indication must be done by a sarcoma treatment specialist. For cytological examination, it is possible to obtain the result already the same or the following day while a histological examination requires a few days.
- Unknown type of lesion in the pelvis
- To confirm or exclude metastases from suspect lesions in the pelvis.
- Ultrasound specimen with transducer for the procedure
- Syringe (20 ml and syringe holder)
- Needle for cytology material. (22 G B&D spinal needle)
- 4 slides for the specimen
For histological biopsy (pistol biopsy) this is used in addition:
- Separate 18 G or 16 G needle + gun
- Slide for fixing histology material (formalin, Ringer solution, McCoy, dry glass for freezing etc. - depending on tentative diagnosis)
- Sterile condom for ultrasound probe
Depending on the localization of the lesion and availability, routine blood tests must be ordered regarding bleeding parameters (hemoglobin, thrombocytes, possibly INR).
- Make sure the patient is well situated on the examination table.
- Inform the patient during the procedure.
Ultrasound-guided biopsy from the pelvis is taken usually under general anesthesia, but fine-needle aspiration for cytology examination can be taken without anesthesia.
Cytology sample (fine-needle aspiration)
- Wash the vagina with chlorhexidine 1 mg/ml
- Localize the lesion with the ultrasound probe
- Determine the best point of puncture and direction. Use a puncture line.
- Puncture the spinal needle quickly through mucous membrane.
- Insert the needle into the lesion using ultrasound.
- Pull out the mandrin.
- Insert the needle into the lesion.
- Aspirate while the needle moves back and forth 2-3 times per second until the material is visible in the upper part of the needle.
- Retract the suction and pull the needle out.
- Deposite the specimen onto the slide
Spread for cytology
- Spread the specimen onto the slide.
- Dry the specimen under a fan or hairdryer.
- Alternative 1: send the specimen unfixed to the cytologist.
- Alternative 2: Immediate staining and assessment.
- Fixation solution with methanol + haemacolor + rinse in water
- 5 dips in fixer. Allow the solution to drip off onto paper.
- 3 dips in stain solution 1.
- 6 dips in stain solution 2. Allow the solution to drip onto paper.
- Rinse in 2 baths of clean water.
- Examine the specimen under the microscope with 10x or 20x objective.
- Microscopic assessment of the cell material should be done by a cytologist to determine if supplementary samples are needed.
Histological biopsy (pistol biopsy)
- For pistol biopsy, general anesthesia is used.
- Insert the biopsy needle up to the lesion and insert slightly, depending on the size and type of the tissue in front and behind the lesion.
- The needle moves 2.5 cm forward when released.
- Retract the pistol such that the sample is taken.
- Retrieve the needle out and open it.
- Place the piece of tissue on a slide with transfer medium, for example formalin.
- After uncomplicated biopsies, outpatients must remain at the hospital for 1 hour before going home.
- Depending on localization of the lesion and nature, bleeding may occur after biopsy procedure.
- For intense pain or bleeding, the patient must be observed at the post or intensive unit dending on severity while necessary measures are taken.