biostudies-literatureUnknown207(3)Johnstone PLarge-cell transformation of mycosis fungoides (LCTMF) is rare, histologically distinct, with an aggressive clinical course; yet is not recognised as an independent entity in classification systems nor in staging systems for mycosis fungoides and Sézary syndrome (MF/SS). Herein, the patterns of care and survival outcomes for patients with LCTMF are described, with prognosis compared to published data of non-transformed MF/SS. Eligibility required clinicopathological diagnosis of LCTMF (1/1/1990-31/10/2021), managed at Peter MacCallum Cancer Centre. Eighty-three patients were eligible. Median follow-up was 8.0 years. At the time of LCTMF, 36% had early-stage MF (IA-IIA), 76% had cutaneous-only LCTMF. The most common first-line treatments were localised radiotherapy (48%) and multiagent chemBritish journal of haematology824-833https://www.ebi.ac.uk/biostudies/studies/S-EPMC12436213biostudies-literatureLarge-cell transformation of mycosis fungoides: Patterns of care and patient outcomes.PMC12436213Higgins MPrince HMvan der Weyden CBlombery PMcCormack CBhabha FJohnstone PBuelens OCampbell BALade SfalseLarge-cell transformation of mycosis fungoides: Patterns of care and patient outcomes.Large-cell transformation of mycosis fungoides (LCTMF) is rare, histologically distinct, with an aggressive clinical course; yet is not recognised as an independent entity in classification systems nor in staging systems for mycosis fungoides and Sézary syndrome (MF/SS). Herein, the patterns of care and survival outcomes for patients with LCTMF are described, with prognosis compared to published data of non-transformed MF/SS. Eligibility required clinicopathological diagnosis of LCTMF (1/1/1990-31/10/2021), managed at Peter MacCallum Cancer Centre. Eighty-three patients were eligible. Median follow-up was 8.0 years. At the time of LCTMF, 36% had early-stage MF (IA-IIA), 76% had cutaneous-only LCTMF. The most common first-line treatments were localised radiotherapy (48%) and multiagent chem2025-01-01T00:00:00Z2025 Sep2026-06-01T14:01:40.446Z2026-04-08T13:17:54.402ZS-EPMC124362134055762310.1111/bjh.20225