High-Scatter Lymphocytes in the Blood of Erythrodermic Cutaneous T-Cell Lymphoma: Evidence for Large-Cell Transformation?

Abstract

Background: Erythrodermic cutaneous T-cell lymphoma consists of erythrodermic mycosis fungoides and Sézary syndrome. Previous studies have indicated that very large Sézary cells (> 14 μm diameter) or the presence of aneuploid cells in the blood might reflect large-cell transformation, with a corresponding poor prognosis. Patients and Methods: A retrospective study assessed data between June 1997 and April 2002 of 32 patients with erythrodermic cutaneous T-cell lymphoma, 4 patients with leukemic mycosis fungoides, and 19 patients with nonneoplastic inflammatory conditions who were referred for evaluation of possible cutaneous T-cell lymphoma. Data were studied by 2-parameter flow cytometry gated on the lymphocyte population. Results: High-scatter T lymphocytes (HSL) were detected in initial blood samples from 10 of 19 patients with Sézary syndrome, 1 of 13 patients with erythrodermic mycosis fungoides, and no patient with nonneoplastic inflammatory conditions. A significant correlation was found between HSL and very large Sézary cells and histopathologic evidence of large-cell transformation. Moreover, the presence of HSL suggests a poor prognosis even for patients with advanced disease. Conclusion: We propose that HSL are often large transformed neoplastic Sézary cells that may be detected in patients with clinically unapparent large-cell transformation.