Considering all skin biopsy samples at diagnosis, CD30 > 10% and Ki67 > 20% was more frequent in LCT+ samples than in LCT- samples (67% vs. 9%; I P i = 0-003 and 100% vs. 22%; I P i = 0-016, respectively). Mean cell surface was significantly higher in LCT+ than in LCT- skin biopsy sample images [27 m SP 2 sp (SD 3-3) vs. 22 m SP 2 sp (SD 2-3); I P i < 0-001]. Dear Editor, Sézary syndrome (SS) is a rare cutaneous T-cell lymphoma (CTCL) grouped with mycosis fungoides (MF) in the international classification and staging criteria of CTCL.1,2 Large-cell transformation (LCT) has been widely described in MF and associated with reduced overall survival, suggesting the importance of early and sequential histological screening of LCT in MF.3 However, LCT has never been studied and characterized in a large cohort of SS. [Extracted from the article]