Rationale: Neurofibromatosis type one (NF1) is characterized by cutaneous and nervous lesions, and the tendency to form plexiform neurofibromas (PNFs). PNFs may undergo malignant transformation into a malignant peripheral nerve sheath tumors (MPNSTs). MPNSTs often carry an significant morbidity and mortality.
Patient concerns: A 17-year-old man with gradually increased multiple subcutaneous soft lesions. He also presented with numerous lentigines and multiple café-au-lait macules on his body.
Diagnoses: These were collagen neurofibroma, which were definitively diagnosed by pathology. NF1 was eventually diagnosed.
Interventions: These lesions were abnormal uptake of radiotracer, when he underwent positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) scanning. Standard uptake value (SUV) and other parameters can help to distinguish benign and malignant lesions in patient with NF1. He was underwent serials F-FDG PET/CT examinations to followed up, in order to monitor these lesions malignant transformation.
Outcomes: So far, these subcutaneous soft lesions were not malignant transformation.
Lessons: F-FDG PET/CT is being increasingly used as an imaging modality to discover the systemic lesions and to discriminate between benign and malignant plexiform neurofibromas.