For the past 20 years, mycosis fungoides and the Sézary syndrome have been recognized as heterogeneous forms of cutaneous T-cell lymphoma (CTCL).1 The former condition typically evolves slowly through progressive phases of localized cutaneous involvement with plaques and tumors with progression to extracutaneous involvement, generally over a period of years. Malignant cells are usually not detected within the blood in early stages of mycosis fungoides. In contrast, the Sézary syndrome presents with diffuse skin involvement (erythroderma), generalized lymphadenopathy, and the presence of circulating malignant lymphocytes. Thus, the Sézary syndrome is considered to be an advanced form of CTCL characterized by widespread dissemination of the malignant lymphocytes.
The neoplastic cells, originally identified in the peripheral blood by Sézary and termed monstrous cells, have maintained the eponym of Sézary cell since that time.2 A hallmark of these cells is the presence of a hyperchromatic nucleus, which, on refined light microscopy and electron microscopy, exhibits deeply
Rook AH, Vowels BR, Jaworsky C, Singh A, Lessin SR. The Immunopathogenesis of Cutaneous T-Cell LymphomaAbnormal Cytokine Production by Sézary T Cells. Arch Dermatol. 1993;129(4):486-489. doi:10.1001/archderm.1993.01680250098016