title: The incidence of secondary central nervous system involvement in patients with non-Hodgkin's lymphoma as detected by 18F-FDG PET/CT.
abstract: OBJECTIVE
  Secondary central nervous system (CNS) involvement is a devastating and usually fatal complication of non-Hodgkin's lymphoma (NHL). We aimed to evaluate the incidence of secondary CNS involvement and the value of (18)F-FDG PET/computed tomography (CT) imaging in the detection of secondary CNS involvement in patients with NHL.
  
  
  METHODS
  A total of 123 immunocompetent patients (58 men, 65 women; mean age: 56.5±19.2) with biopsy-proven NHL who underwent (18)F-FDG PET/CT for primary staging (n=68) and restaging (n=55) of recurrent disease were reviewed retrospectively. Those with secondary CNS involvement as diagnosed on PET/CT were identified. CNS involvement was confirmed by MRI and cerebrospinal fluid cytology.
  
  
  RESULTS
  The clinical Ann Arbor stages of the patient population were as follows: stage I - 10 patients; stage II - 44 patients; stage III - 32 patients, and stage IV - 37 patients. PET/CT detected CNS involvement in six patients. The ages of patients with CNS disease ranged from 23 to 68 (mean: 47.2) years. Three patients presented with CNS involvement associated with systemic disease manifestation at initial diagnosis; one patient had isolated CNS relapse and two had relapsed systemic NHL with progression to CNS involvement. Relapse interval was 8-12 months following initial diagnosis. The types of CNS involvement in patients were as follows: parenchymal (n=2), leptomeningeal (n=2), both parenchymal and leptomeningeal (n=1), and pituitary gland involvement (n=1), which is an uncommon manifestation. Median duration of survival was 2.5 months after the diagnosis of CNS involvement.
  
  
  CONCLUSIONS
  The incidence of secondary CNS involvement was 4.4% at initial diagnosis and 5.4% among patients with relapse of lymphoma in our study. PET/CT is a sensitive, objective, and valuable method for the diagnosis of secondary CNS involvement in patients with NHL. In addition, pituitary gland involvement, as a very rare manifestation of secondary CNS lymphoma, has been shown.
authors.affiliation: Department of Nuclear Medicine, Ankara Oncology Research and Training Hospital, Ankara, Turkey. burcuesen@yahoo.com
authors.forename: Burcu E
authors.initials: BE
authors.lastname: Akkas
authors.forename: Gulin U
authors.initials: GU
authors.lastname: Vural
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002493:Central Nervous System Diseases / Q000150:complications* / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D015994:Incidence; D008228:Lymphoma, Non-Hodgkin / Q000150:complications* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18