Fig 1.
Example of a 19-year-old woman with rapidly growing peripheral neurofibroma in the upper right thigh ("at-risk" score = 25).
(A) Maximum intensity projection. (B) CT image in axial view. (C) PET/CT fusion. (D) 18F-FDG PET images after drawing a spherical volume-of-interest around the intramuscular tumour: the metabolic volume corresponds to the sum of voxels above a 41% SUVmax threshold (green color). (E) Contrast-enhanced MRI. Metabolic measures suggest MPNST transformation (SUVmax = 12.5, TMTV = 389 cm3, TLG = 2323, T/L ratio = 6.2), confirmed by histopathological study (sarcoma grade 3). To note, intratumoral heterogeneity is present in the right thigh mass (black arrow) although whole-body heterogeneity index is below the predictive threshold (HIsuv = 1.68). Patient was treated with m-TOR inhibitors and died 6 months later.
Table 1.
Clinical characteristics.
Fig 2.
Box-plot repartition of SUVmax (A), TMTV (B) and TLG (C) in the three histopathological groups of tumours.
Table 2.
Univariate analyses of all population.
Table 3.
Performance of PET/CT metabolic parameters to distinguish sarcoma from benign NF, dysplastic NF and no sign of transformation at follow-up (n = 49).
Fig 3.
Kaplan-Meier estimates of overall survival with number of patients at risk at different time points depending on histopathology (A) and metabolic measures: T/L ratio (B), SUVmax (C), TLG (D), TMTV (E), HIsuv (F) calculated in the whole population (n = 49, median follow-up 50 mo).