Cryoablation of a polylobulated dedifferentiated liposarcoma in right femur

Cryoablation of a polylobulated dedifferentiated liporsarcoma of 12 x 7 cm of the quadriceps muscle. Treatment using eight ablation needles required great precision due to proximity of the tumour to the femoral nerve. Tumour debulking intends to reduce symptoms by size reduction and softening of the tissue to mobilize the patient and improve quality of life.

Planning of eight cryo probes
Verification of probe position
Imaging of freezing cycle also showing a sterile glove filled with warm water to protect the skin of the patient

Name: Dr. Robyn M. Benz 

Institution: Inselspital, Bern (Switzerland)

Patient age and sex: 94 years, male

Initial condition:

  • Initial diagnosis 2019 (N0, cM0)
  • Radiation treatment in 2019 with initial reduction of size of the tumour
  • Tumour regrowth in autumn 2021 with recurring symptoms of pain and skin tension over the tumour, inhibiting walking and reducing quality of life of a patient in an otherwise good physical condition
  • Repeated radiation was not indicated
  • Clinical exam showed increase of diameter of right thigh and soft tissue induration and pain upon pressure in the area of the tumour. Tension of skin over the tumour was also clearly visible
  • Indication for percutaneous tumour treatment as the patient refused surgery and systemic therapy


  • Accurate placement of all eight needles at first go with an average lateral error of 1,7 mm
  • Probe placement was completed within 70 min including two control scans


  • Planning, navigation and verification of eight probes resulted in a complex clinical scenario
  • Preplanning of the intervention started one week prior to treatment
  • Access to the trajectories by avoiding previously placed probes is narrow but possible. Diligent planning and execution required
  • Overall intervention time was four hours. The patient tolerated the intervention well
  • Treatment can be considered a technical success, as most of the tumour volume was covered with the cryo ablation 
  • Follow-up is yet to be conducted

Learn more about the stereotactic navigation system CAS-One IR.

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