title: Early 2'-deoxy-2'-[18F]fluoro-D-glucose PET metabolic response after corticosteroid therapy to differentiate cancer from sarcoidosis and sarcoid-like lesions.
abstract: OBJECTIVE
  We aimed at investigating whether early metabolic response to corticosteroid therapy may be used as a diagnostic tool to discriminate between cancer and sarcoidosis, a well-known cause of false-positive 2-deoxy-2-[F-18]fluoro-D: -glucose-positron emission tomography (FDG-PET) findings in oncology.
  
  
  METHODS
  Two cancer patients with biopsy-proven sarcoidosis or sarcoid-like reaction had multiple thoracic FDG foci. After infectious disease had been excluded, patients received oral corticosteroids for 16 and 14 days, respectively, and underwent posttherapeutic FDG-PET examination.
  
  
  RESULTS
  Posttreatment PET revealed a complete metabolic response in both patients, and clinical and imaging follow-up showed no sign of cancer progression.
  
  
  CONCLUSIONS
  Early metabolic response to systemic corticosteroid treatment may be used as a tool in the establishment of final diagnosis when sarcoidosis is suspected in a cancer patient and could be capable of differentiating cancer from sarcoidosis in the case of coexisting diseases.
authors.affiliation: Nuclear Medicine Department, François Baclesse Comprehensive Cancer Centre, Caen, France. n.aide@baclesse.fr
authors.forename: Nicolas
authors.initials: N
authors.lastname: Aide
authors.forename: Djelila
authors.initials: D
authors.lastname: Allouache
authors.forename: Yann
authors.initials: Y
authors.lastname: Ollivier
authors.forename: Sixtine
authors.initials: S
authors.lastname: de Raucourt
authors.forename: Odile
authors.initials: O
authors.lastname: Switsers
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bardet