title: Histologic transformation in marginal zone lymphomas†.
abstract: BACKGROUND
  Histologic transformation (HT) is a poorly understood event in patients with marginal zone lymphoma (MZL). The aim of this study was to analyze incidence and risk factors for HT in a large series of MZL patients.
  
  
  METHODS
  The studied cohort included 340 MZL patients diagnosed and treated between 1995 and 2012: 157 extranodal MZLs [mucosa-associated lymphoid tissue (MALT) lymphoma, 46%], 85 splenic MZLs (SMZLs, 25%) and 37 nodal MZLs (NMZLs, 11%). Sixty-one patients (18%) had bone marrow infiltration at presentation, with or without detectable involvement of peripheral blood, but without other involved sites; they were considered clonal B-cell lymphocytosis of marginal zone origin (CBL-MZ).
  
  
  RESULTS
  With a median follow-up of 4.8 years, the median overall survival and progression-free survival of the whole population were 14.5 and 5 years, respectively. HT was observed in 13 cases [3.8%, 95% confidence interval (95% CI) 2%-6.5%]. Elevated lactate dehydrogenase (LDH) at diagnosis was associated with the risk of HT (P = 0.019). HT occurred in 5% of SMZLs, 4% of MALT lymphomas, 3% of NMZLs and 3% of CBL-MZ (P = 0.974). The risk of HT was 5% (95% CI 3-9%) at 5 and 10 years after diagnosis and 10% (95% CI 5%-20%) at 12 years. At the time of HT, most patients had high LDH and B symptoms. At a median follow-up of 12 months after HT, 4 of 13 patients died, all for lymphoma-related causes, with a 2-year post-transformation survival rate of 57% (95% CI 13%-86%).
  
  
  CONCLUSIONS
  In this large retrospective series, the risk of HT across all MZL types appeared lower than the one reported for follicular lymphoma.
authors.affiliation: Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, A.O.U. Maggiore della Carità, Novara Hematology Unit, Department of Internal Medicine, Ospedale degli Infermi, Biella, Italy annarita.conconi@aslbi.piemonte.it.
authors.forename: A
authors.initials: A
authors.lastname: Conconi
authors.affiliation: Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, A.O.U. Maggiore della Carità, Novara.
authors.forename: S
authors.initials: S
authors.lastname: Franceschetti
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona.
authors.forename: K
authors.initials: K
authors.lastname: Aprile von Hohenstaufen
authors.affiliation: Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, A.O.U. Maggiore della Carità, Novara.
authors.forename: G
authors.initials: G
authors.lastname: Margiotta-Casaluci
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona.
authors.forename: A
authors.initials: A
authors.lastname: Stathis
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona.
authors.forename: A A
authors.initials: AA
authors.lastname: Moccia
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona Lymphoma and Genomics Research Program, Institute of Oncology Research (IOR), Bellinzona, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Bertoni
authors.affiliation: Institute of Pathology, A.O.U. Maggiore della Carità, Novara, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Ramponi
authors.affiliation: Lymphoma Unit, Institute of Pathology, Locarno, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Mazzucchelli
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona.
authors.forename: F
authors.initials: F
authors.lastname: Cavalli
authors.affiliation: Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, A.O.U. Maggiore della Carità, Novara.
authors.forename: G
authors.initials: G
authors.lastname: Gaidano
authors.affiliation: Oncology Institute of Southern Switzerland (IOSI), Bellinzona.
authors.forename: E
authors.initials: E
authors.lastname: Zucca
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D055815:Young Adult
keywords: histologic transformation; marginal zone lymphoma; risk factors