title: Primary mediastinal B-cell lymphoma with sclerosis: an aggressive tumor with distinctive clinical and pathologic features.
abstract: OBJECTIVE
  To evaluate the clinical features of presentation, the morphologic and immunohistochemical pattern, the modality of spread, and the response to current treatments of patients with primary mediastinal B-cell lymphoma, a recently documented subtype of non-Hodgkin's lymphoma (NHL).
  
  
  METHODS
  Thirty consecutive patients (14 males, 16 females; median age, 26 years) with primary mediastinal B-cell lymphoma with sclerosis were studied.
  
  
  RESULTS
  The clinical aspects were largely homogeneous: 93% presented with chest symptoms of a rapidly enlarging mass of the anterior mediastinum; the tumor was bulky in 73%, and superior vena cava syndrome (SVCS) was present in 57%. Also, patients without SVCS symptoms showed subclinical venacaval compression at computed tomographic (CT) scan, for a total incidence of caval obstruction of 80%. Intrathoracic extension to adjacent organs was seen in 47% of patients. Despite its invasive behavior, only four patients showed extrathoracic spread at diagnosis. In 23 cases, the tumor presented with morphologic features that resembled follicular center-cell lymphomas. In seven, the neoplastic population was composed mainly of centrocyte-like cells with abundant clear cytoplasm not referable to any known B-cell lymphoma subtype. All cases showed huge sclerosis. Of 29 patients assessable for response, 16 (55%) achieved a complete response (CR): five of 14 (36%) treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), and 11 of 15 (73%) treated with methotrexate plus leucovarin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B) or etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (VACOP-B) (P = .047). We could identify no clinical, biologic, or histopathologic features significantly correlated with response. After chemotherapy, 14 of 16 remitters received consolidation radiotherapy to the mediastinum. At 3 years, the actuarial survival rate is 38% for all cases and 72% for remitters. None of the 13 patients who did not achieve CR responded to salvage treatments.
  
  
  CONCLUSIONS
  This study shows that primary mediastinal B-cell lymphoma with sclerosis is a distinctive subtype of NHL with unique clinicopathologic aspects and aggressive behavior. Prompt recognition and aggressive treatment may provide long survival in a good proportion of cases. However, a subset of patients is extremely refractory to first- and second-line treatment. Conventional prognostic factors seem inadequate to identify these very-poor-risk cases.
authors.affiliation: Institute of Hematology, University of Pavia, Policlinico S. Matteo, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Lazzarino
authors.forename: E
authors.initials: E
authors.lastname: Orlandi
authors.forename: M
authors.initials: M
authors.lastname: Paulli
authors.forename: E
authors.initials: E
authors.lastname: Boveri
authors.forename: E
authors.initials: E
authors.lastname: Morra
authors.forename: E
authors.initials: E
authors.lastname: Brusamolino
authors.forename: S
authors.initials: S
authors.lastname: Kindl
authors.forename: R
authors.initials: R
authors.lastname: Rosso
authors.forename: C
authors.initials: C
authors.lastname: Astori
authors.forename: M C
authors.initials: MC
authors.lastname: Buonanno
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016393:Lymphoma, B-Cell / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology*; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology*; D012598:Sclerosis; D016019:Survival Analysis; D016896:Treatment Outcome