Peripheral blood involvement in mycosis fungoides (MF) patients is more frequent in the advanced stages and is associated with a worse prognosis. We report a MF patient with limited patch lesions on her shoulders, upper chest and thighs (T2N0M0) and peripheral blood involvement. Clonality in the peripheral blood was demonstrated by the PCR assay and confirmed by the expansion of the same restricted variable region of the TCR beta-chain (vbeta17) expressed in the cutaneous infiltrate. The patient was treated with fludarabine achieving a complete hematological response followed by an early relapse, whilst the cutaneous lesions remained unchanged. The soluble interleukin-2 receptor levels showed a decrease from baseline levels down to normal values at hematological remission, followed by a further increase. The low sLex/CLA expression in the cutaneous lymphoid infiltrate could have given rise to a higher recruitment in the peripheral blood.