Sézary syndrome is a leukemic variant in the spectrum of cutaneous T cell lymphomas. In some cases of cutaneous T cell lymphoma, the skin tumors or lymph nodes show morphologic changes indistinguishable from those of a large-cell lymphoma; this has been termed transformation. We report a case of Sézary syndrome who developed multiple skin tumors that showed transformation, loss of multiple pan T-cell markers (CD3, 4, 5, 7, 8), and a concomitant expression of CD30 during the course of the disease. Some of the tumors spontaneously regressed following incisional biopsy or traumatic wounds. The patient died of pneumonia five years following the transformation.