Incidence and clinicopathological features of Follicular T-cell lymphoma in Finland: a population-based immunohistochemical study.

Follicular T-cell lymphoma (FTCL) is a rare subtype of mature T-cell lymphoma. It was recently recognized as a separate lymphoma entity in the 2017 revised fourth edition of the World Health Organization classification. The main goals of the present study were to gain better knowledge of the incidence and histopathological and clinical features of FTCL in Finland. In this study, we reviewed all angioimmunoblastic T-cell (AITL) and peripheral T-cell lymphomas, not otherwise specified, from the patient records in three hospital districts in Finland over a 10-year period, to identify FTCL cases and estimate its incidence. Five patients rediagnosed with FTCL and 34 with AITL were analyzed. Hodgkin/Reed-Sternberg (HRS)-like cells were observed in 24 of the 34 AITL cases and four of the five FTCL cases. We found that the main features that differentiated FTCL from AITL were rosetting of T-cells around HRS-like cells, the absence of clear cells, follicular dendritic cell meshwork and T-cell monoclonality. Our estimated incidence of FTCL is 0.20 per 100,000 people in Finland.

Prognostic significance of Twist, ZEB1 and Slug in peripheral T-cell lymphomas.

ABSTRACT Objectives: To investigate the protein expression of the epithelial-mesenchymal transition-inducing transcription factors (TFs) Twist, ZEB1 and Slug in peripheral T-cell lymphomas (PTCL) and their correlation with clinical parameters. Methods: The expression of these TFs was studied in 53 diagnostic biopsy specimens of several different PTCL subtypes with immunohistochemistry. Patient data were retrospectively collected from patient records and a statistical analysis was performed. Results: All three TFs were widely expressed. ZEB1 and Slug had correlations with clinical outcome. In all PTCL cases, high nuclear ZEB1 percentage correlated with a favorable progression-free survival (PFS) (3-year PFS: 70% vs. 34%; P = 0.010) and strong nuclear Slug intensity correlated with an unfavorable PFS (3-year PFS: 17% vs. 62%; P = 0.036). Discussion: The correlations between PFS and ZEB1 or Slug protein expression have not previously been established in PTCLs. The impact of ZEB1 and Slug expression on prognosis differed from our findings in DLBCL and the impact of ZEB1 expression was in line with current studies on mycosis fungoides and sézary syndrome. The findings may be explained by the roles these TFs play in hematopoiesis. Conclusion: ZEB1 and Slug may have potential clinical value for evaluating prognosis in PTCLs. The study size was small and heterogenous, and larger studies are warranted.