title: Sarcoidosis mimicking lymphoma on positron emission tomography-computed tomography in two patients treated for lymphoma: two case reports.
abstract: BACKGROUND
  Sarcoidosis is a granulomatous disease that mostly involves the lungs. Its association with malignancies has been well documented. Several mechanisms have been proposed that may underlie this concurrence including triggering tumour antigens and defective cellular immunity.
  
  
  METHODS
  We briefly review the literature on malignancy associated sarcoidosis and report two female lymphoma patients of 49 and 56 years of age who, during their course of disease, developed sarcoidosis that was misinterpreted as a lymphoma relapse on positron emission tomography-computed tomography.
  
  
  CONCLUSIONS
  We hypothesise that T cell dysfunction and exposure to tumour associated antigens might be the underlying mechanisms of development of sarcoidosis in patients with lymphoma. Positron emission tomography-positive lesions do not always indicate malignancy and therefore a tissue biopsy is always mandatory to confirm the diagnosis.
authors.forename: Ozden
authors.initials: O
authors.lastname: Ozer
authors.forename: Ahmet Emre
authors.initials: AE
authors.lastname: Eskazan
authors.forename: M Cem
authors.initials: MC
authors.lastname: Ar
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Beköz
authors.forename: Fehmi
authors.initials: F
authors.lastname: Tabak
authors.forename: Gül
authors.initials: G
authors.lastname: Ongen
authors.forename: Burhan
authors.initials: B
authors.lastname: Ferhanoglu