title: An old enemy not to be forgotten during PET CT scanning of cancer patients: tuberculosis.
abstract: OBJECTIVE
  Positron emission tomography-computed tomography (PET CT) scan is commonly used in current medical oncology practice as an imaging method. In this study we present data from cancer patients who were followed at our clinic and suspected of having tuberculosis during PET CT scanning. After the biopsy, they were diagnosed with concomitant tuberculosis.
  
  
  METHODS
  In this study, 14 patients who applied to our clinic and followed up due to cancer, and had PET CT scanning for the preliminary staging or further evaluation, were included. The patients were diagnosed with metastatic or recurrent disease, and their biopsy results revealed tuberculosis.
  
  
  RESULTS
  The mean age was 57.8 years with SD (standard deviation) 13.1 years and gender distribution of 78.6% (n = 11) females and 21.4% (n = 3) males. None of the patients had tuberculosis in their personal history (0%). Among the patients, 5 (35.7%) were diagnosed with tuberculosis during the preliminary staging, whereas 9 (64.3%) were diagnosed during the follow-up after the treatment. The median time to tuberculosis diagnosis was 11 months (min-max: 3-24 months) after the treatment. The most commonly involved lymph nodes during PET CT scanning were mediastinal in 8 (64.3%), axillary in 3 (21.4%) and para-aortic in 3 (21.4%) patients. The mean SUVmax (maximum standardised uptake value) of lymph node involved by PET CT scanning was defined as 8.5 (SD 2.6).
  
  
  CONCLUSIONS
  Despite all improvements in modern medicine, tuberculosis is still a serious public health problem. It should always be considered in differential diagnosis while evaluating PET CT scanning results of cancer patients, because it may cause false positive results.
authors.affiliation: Department of Medical Oncology, Medical Faculty, Mustafa Kemal University, Antakya, Turkey.
authors.forename: Ahmet Taner
authors.initials: AT
authors.lastname: Sümbül
authors.affiliation: Department of Medical Oncology, Medical Faculty, Baskent University, Ankara, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Sezer
authors.affiliation: Department of Medical Oncology, Medical Faculty, Baskent University, Ankara, Turkey.
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Abali
authors.affiliation: Department of Microbiology, Medical Faculty, Bezmialem University, Istanbul, Turkey.
authors.forename: Bilge
authors.initials: B
authors.lastname: Gültepe
authors.affiliation: Department of Pathology, Medical Faculty, Baskent University, Ankara, Turkey.
authors.forename: Emrah
authors.initials: E
authors.lastname: Koçer
authors.affiliation: Department of Nucleer Medicine, Medical Faculty, Baskent University, Ankara, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Reyhan
authors.affiliation: Department of Medical Oncology, Medical Faculty, Mustafa Kemal University, Antakya, Turkey.
authors.forename: Önder
authors.initials: Ö
authors.lastname: Tonyalı
authors.affiliation: Department of Medical Oncology, Medical Faculty, Baskent University, Ankara, Turkey.
authors.forename: Özgür
authors.initials: Ö
authors.lastname: Özyilkan
keywords: PET CT; cancer; tuberculosis