title: Prevalence of synchronous second primary malignancy: identification using whole body PET/CT imaging.
abstract: OBJECTIVE
  To describe the prevalence of synchronous second primary malignancy detected by PET/ CT in our clinical practice and its differentiating features from metastatic lesion.
  
  
  METHODS
  All PET/CT scans from 1st October 2009 to 30th September 2010 were reviewed. The suspected cases of synchronous second primary malignancy detected by PET/CT were selected, and the histologically confirmed ones were being illustrated. Metachronous second primary cases were excluded.
  
  
  RESULTS
  A total of 1522 scans were reviewed. sixty-eight cases were suspected to have a synchronous second primary while 8 were histologically confirmed. Seven (0.4%) of them were malignant and 1 was a benign tumor. These 7 cases were illustrated, and we found a significant difference in SUV(max) values and site of occurrence unusual to metastasis that were the two main radiological features differentiating them from metastatic lesion.
  
  
  CONCLUSIONS
  Synchronous second primary malignancy could be missed without the use of whole body imaging. Its diagnosis is of utmost importance to prevent erroneous upstaging of disease and subsequent palliative treatment instead of curative surgery.
authors.affiliation: Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. Electronic address: drcswong@gmail.com.
authors.forename: Wong
authors.initials: W
authors.lastname: Chun-Sing
authors.affiliation: Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Gong
authors.initials: G
authors.lastname: Nan-Jie
authors.affiliation: Department of Radiology, Kwong Wah Hospital, Hong Kong.
authors.forename: Chu
authors.initials: C
authors.lastname: Yiu-Ching
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009369:Neoplasms / Q000473:pathology*; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging* / Q000453:epidemiology; D049268:Positron-Emission Tomography; D015995:Prevalence; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: PET/CT; Synchronous second primary