Evaluation of Percutaneous Cryotherapy in the Treatment of Plexiform Neurofibromas and Unresectable Neurofibromas in Neurofibromatosis Type 1

Inclusion Criteria:

* Age ≥18 years;
* Patient with neurofibromatosis type 1 according to NIH criteria ;
* Patient with a benign neurofibromatous lesion that is painful and/or generates functional discomfort and is unresectable or with unacceptable scarring ;
* Neutrophils \> 1 G/l in the 14 days prior to inclusion;
* Adequate coagulation test with normals values (as judged by the investigator);
* Signed and dated informed consent document indicating that the patient has been informed of all aspects of the trial prior to enrolment
* Covered by a medical insurance;

Exclusion Criteria:

* Patient treated with concomitant chemotherapy and/or targeted therapies ;
* Any contraindication to a percutaneous cryotherapy procedure, including the need for ice formation within 1 cm of the spinal cord, brain or other critical nerve structures, bowel or bladder (unless active or passive thermal protective maneuvers are performed);
* Patient with malignant neurofibroma or MPNST ; CT scan without abnormality and if tumor presents a max SUV T/F\>1.5 ratio, targeted biopsy is required to confirm benign or malignant histology.
* Patient with neurofibroma in areas at risk for neurological sequelae;
* Patient with cold urticaria with history of angioedema;
* Any cognitive impairment or condition that may limit the use of numerical scales and quality of life questionnaires;
* Patient for whom follow-up does not seem feasible even in the short term;
* Participation in another clinical trial that may interfere with the evaluation of the primary endpoint;
* Patient under tutorshio, curatorship or deprived of liberty;
* Pregnant or breast-feeding woman;
* Any contraindication to the performance of an MRI
* Patient with dysplastic neurofibroma