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