Mediastinal gray zone lymphoma-morphollogically heterogenous group of lymphomas.

Abstract

e19050 Background: Mediastinal Gray zone lymphoma (MGZL) could be refer to group of large B-cell lymphomas of mediastinum, where Hodgkin’s lymphoma and Diffuse large B-cell lymphoma also included. These kinds of lymphomas have common pathogenic mechanisms, but different epidemiological,clinical , morphological, IHC features, different therapy and prognosis. Methods: We analyzedhistological and IHC features of 11 patients with MGZL. Middle age of patients were 35 years old (25-42), Man(7 )and woman (4) ratio was 1,75:1. Results: We distinguished 5 types of MGZL: 1) Hodgkin’s lymphoma-like variant (ring-shaped fibrosis, expressed cellular polymorphism, large cells seems like Hodgkin’s and Reed-Shteinberg cells,mixed-cell background infiltrate; high expression of CD 20 and another B-lines antigens. 2) type, seems like primary mediastinum large B-cell lymphoma (PMBL-like) (about monotonous composition of the cells, diffuse alveolar stroma’sfibrosis, scarce background infiltrate, high diffuse expression of CD 30 and/or lack of LCA and CD 20 expression 3) mixed variant (mixture of cells PMBL and Hodgkin's lymphoma, irregularly expressed fibrosis, lack of zonality, transientimmunophenotype. 4) dual-component variant (well-defined zonality, Hodgkin's like areas and structuresspecific for PMBL with appropriate or changed immunophenotype 5) Metachronous variant (during progression or relapse we observedmodification of morphological and IHC features). Conclusions: MGZL is heterogenous group of neoplasms with different morphological and IHC features causes difficulties in differential diagnostics in large B-cell lymphomas of mediastinum group.Diagnostic algorithm should be used for high efficacy and accuracy. Clinical features and prognostic factors in these subtypes of MGZL is still unclear and need further investigations.