[1282] Cutaneous CD4-Positive Small/Medium-Sized Pleomorphic T-Cell Lymphoma Expresses Follicular T-Cell Markers

SM Rodriguez-Pinilla, G Roncador, JL Rodriguez-Peralto, M Mollejo, JF Garcia, S Montes-Moreno, FI Camacho, P Ortiz, MA Limeres-Gonzalez, A Torres, E Campo, P Navarro-Conde, MA Piris. CNIO, Madrid, Spain; Hospital 12 de Octubre, Madrid, Spain; Hospital de Gran Canaria, Gran Canaria, Spain; Hospital Rio Hortega, Valladolid, Spain; Hospital Clinic, Barcelona, Spain; Hospital Arnau de Vilanova, Valencia, Spain

Background: Cutaneous CD4+ small/medium-sized- pleomorphic T-cell lymphoma (CSTCL) is a cutaneous T- cell- lymphoma defined by a predominance of small-to-medium-sized- CD4+- pleomorphic- T- cells, with a favorable clinical course. Cases are also characterized by the presence of a rich infiltrate of reactive B- cells. Recently, it has been reported that follicular helper- T- cells (T_FH- cells) display a distinct gene expression profile, positive for PD-1, CXCL13, and BCL-6. We investigate here the expression of PD-1 and other T_FH- cells markers in CSTCLs and discuss its biological significance.
Design: Sixteen CSTCLs were included in this study, 20 reactive inflammatory conditions, 10 primary cutaneous marginal zone, 10 cutaneous follicular center and 5 primary CD30+ cutaneous lymphomas. They were immunohistochemically analyzed for a large panel of markers. Double immunoperoxidase labeling of paraffin sections was performed for PD-1, OCT-2, and BCL-6. Clonal Ig and TCR rearrangements and EBV (EBER) expression were also evaluated. Morphological and clinical data were reviewed.
Results: There was a dense polymorphic lymphoid infiltrate throughout the dermis. Atypical- large CD4-positive cells were positive for PD1, CXCL13, and BCL6 in all cases, and were attached in small clusters, or formed rosettes around CD30/OCT2-positive B-cell blasts. EBV was not detected in any of the cases. A dominant T-cell clone was identified in 14 cases, while all cases were polyclonal for IgH. None of the patients had lymphadenopathy, showed any evidence of systemic disease, nor did have any previous history of mycosis fungoides or drug reactions.
Conclusions: F_TH-cell markers are not exclusive to angioimmunoblastic T-cell lymphoma, but may also be seen in neoplastic cells of CSTCLs and rarely in mycosis fungoides. Moreover, these findings suggest that B cell stimulation by F_TH could also take place in some cutaneous T -cell lymphomas, thus offering an explanation for the increased number of reactive B-cells regularly present in this lymphoma type.
Category: Hematopathology

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 191, Wednesday Morning