title: Bone marrow involvement in diffuse large B-cell lymphoma: correlation between FDG-PET uptake and type of cellular infiltrate.
abstract: OBJECTIVE
  To assess, in patients with diffuse large B-cell lymphoma (DLBCL), whether the low sensitivity of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for bone marrow assessment may be explained by histological characteristics of the cellular infiltrate.
  
  
  METHODS
  From a prospective cohort of 110 patients with newly diagnosed aggressive lymphoma, 21 patients with DLBCL had bone marrow involvement. Pretherapeutic FDG-PET images were interpreted visually and semiquantitatively, then correlated with the type of cellular infiltrate and known prognostic factors.
  
  
  RESULTS
  Of these 21 patients, 7 (33%) had lymphoid infiltrates with a prominent component of large transformed lymphoid cells (concordant bone marrow involvement, CBMI) and 14 (67%) had lymphoid infiltrates composed of small cells (discordant bone marrow involvement, DBMI). Only 10 patients (48%) had abnormal bone marrow FDG uptake, 6 of the 7 with CBMI and 4 of the 14 with DBMI. Therefore, FDG-PET positivity in the bone marrow was significantly associated with CBMI, while FDG-PET negativity was associated with DBMI (Fisher's exact test, p=0.024). There were no significant differences in gender, age and overall survival between patients with CBMI and DBMI, while the international prognostic index was significantly higher in patients with CBMI.
  
  
  CONCLUSIONS
  Our study suggests that in patients with DLBCL with bone marrow involvement bone marrow FDG uptake depends on two types of infiltrate, comprising small (DBMI) or large (CBMI) cells. This may explain the apparent low sensitivity of FDG-PET previously reported for detecting bone marrow involvement.
authors.affiliation: Department of Nuclear Medicine, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris 12, F-94000 Créteil, France.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Paone
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Itti
authors.forename: Corinne
authors.initials: C
authors.lastname: Haioun
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaulard
authors.forename: Jehan
authors.initials: J
authors.lastname: Dupuis
authors.forename: Chieh
authors.initials: C
authors.lastname: Lin
authors.forename: Michel
authors.initials: M
authors.lastname: Meignan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008495:Medical Oncology / Q000379:methods; D008875:Middle Aged; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D012680:Sensitivity and Specificity
chemical_list: D019788:Fluorodeoxyglucose F18