title: FDG-PET for preoperative differential diagnosis between benign and malignant soft tissue masses.
abstract: OBJECTIVE
  To evaluate the standardized uptake value (SUV) of [(18)F]2-deoxy-2-fluoro- d-glucose at positron emission tomography (FDG-PET) for preoperative differential diagnosis between benign and malignant soft tissue masses.
  
  
  METHODS
  One hundred and fourteen soft tissue masses (80 benign, 34 malignant) were examined by FDG-PET prior to tissue diagnosis. The SUVs were calculated and compared between benign and malignant lesions and among different histologic subgroups which included three or more cases.
  
  
  RESULTS
  There was a statistically significant difference in SUV between benign (1.80+/-1.42 [SD]) and malignant (4.20+/-3.16) soft tissue masses in total (P<0.0001). However, a considerable overlap in SUV was observed between many benign and malignant lesions. Liposarcomas (2.16+/-1.72) and synovial sarcomas (1.60+/-0.43) did not show significantly higher SUV than any benign lesions. Metastases (4.23+/-2.35) showed no statistically significant difference in SUV as compared with schwannomas (1.75+/-0.84), desmoids (2.77+/-1.32), sarcoidosis (3.62+/-1.53), or giant cell tumors of tendon sheath (GCT of TS; 5.06+/-1.63). Even malignant fibrous histiocytomas (5.37+/-1.40) could not be differentiated from sarcoidosis or GCT of TS, based on the SUV.
  
  
  CONCLUSIONS
  A large accumulation of FDG can be observed in both benign and malignant histiocytic, fibroblastic, or neurogenic lesions. SUV at conventional FDG-PET is limited to differentiating benign from malignant soft tissue masses, when all kinds of histologic subtypes are included.
authors.affiliation: Department of Diagnostic Radiology, Gunma University School of Medicine, 3-39-22 Showa-machi, 371-8511 Maebashi, Japan. junaoki@showa.gunma-u.ac.jp
authors.forename: J
authors.initials: J
authors.lastname: Aoki
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Shinozaki
authors.forename: K
authors.initials: K
authors.lastname: Takagishi
authors.forename: M
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Y
authors.initials: Y
authors.lastname: Koyama
authors.forename: N
authors.initials: N
authors.lastname: Sato
authors.forename: K
authors.initials: K
authors.lastname: Endo
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging*; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18