Introduction: Large cell transformation (LCT) of mycosis fungoides (MF) is associated with an aggressive clinical course, poor overall survival (OS), and variable CD30 expression.
Patients and methods: We retrospectively analyzed 1900 MF/Sézary syndrome patients' clinical, histologic and immunophenotype and identified 187 patients seen between 1982 and 2012.
Results: Most advanced stage patients with LCT were male 86 of 155 (55.4%) and 69 were female (44.5%). Incidence of LCT (n = 187) was 9.8% (187/1900) in skin and/or nodes of the entire MF/SS database population (n = 1900). Advanced stage patients represented 83% of patients whose median OS was 4.1 years (95% confidence interval [CI], 3.5-5.4). Early stage patients represented 17% with OS of 8.0 years. Among 187 LCT patients, 136 patients (73%) were diagnosed with LCT at the time of initial diagnosis of MF. Their median OS was 3.6 years (95% CI, 3.3-5.3). Of the 51 patients who had LCT diagnosed after their initial diagnosis of MF, their median OS was 8.8 years (P = .0001; 95% CI, 1.6-4.1). The OS for all LCT patients was 4.8 years, for patients older than 60 years of age OS was 3.7 years (95% CI, 2.7-5.4) and was 6.2 years (95% CI, 4.5-9.8) for patients younger than 60 years of age (P = .0001). An increased lactate dehydrogenase level was associated with a decreased OS (P = .03; hazard ratio, 1.5; 95% CI, 1.0-2.2). Patients with CD30 expression in ≥ 10% of the lymphocytes in skin biopsies were 40% more likely to survive than patients with low expression.
Conclusion: In summary, risk factors associated with disease progression were advanced age, LCT at the time of initial diagnosis of MF, high levels of lactate dehydrogenase, and CD30 expression < 10%.
Keywords: Anaplastic large T cell lymphoma; CD30 cutaneous T-cell lymphoma; CD30(+) lymphoproliferative disorders; Cutaneous T cell lymphoma; Overall survival.
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