CD25+ folliculotropic Sézary syndrome with CD30+ large cell transformation.

Folliculotropic Sézary syndrome is a rare and unique variant of cutaneous T-cell lymphoma (CTCL) characterised by both follicular and leukaemic involvement of mycosis fungoides (MF). It is associated with a more aggressive clinical course and fatal outcomes. Large cell transformation (LCT) of mycosis fungoides/Sézary syndrome is also associated with an aggressive disease course and shortened survival, requiring an intensive therapeutic approach. This report describes a case of folliculotropic Sézary syndrome with CD30+ LCT. Most of the larger lymphocytes in the lesions were positive for CD25, the expression of which is associated with advanced CTCL. In addition, we review the literature on this unusual CTCL and provide evidence that this entity represents a distinct clinicopathological entity occasionally associated with extracutaneous involvement and LCT.