SS is a leukemic variant of CTCL that occurs exclusively in adults. It is characterized by the triad of diffuse erythroderma, generalized lymphadenopathy, and circulating malignant T cells with cerebriform nuclei, the so-called Sézary cells.
Clinical findings include severe scaling or fissuring of the palms and soles, alopecia, and onychodystrophy. The erythroderma may be associated with marked exfoliation, edema, and lichenification and is extremely pruritic .
SS demonstrates histologic features similar to those of MF. Therefore, several diagnostic criteria proposed by the International Society for Cutaneous Lymphoma—including biopsy findings consistent with CTCL, absolute Sézary cell count in the peripheral blood of at least 1000 cells/mm, and, by fluorescence-activated cellsorting analysis, an increased CD4/CD8 ratio of more than 10, a CD7- phenotype (more than 40 percent), and evidence of
a circulating T-cell clone—were included in the WHO-EORTC classification.1 Patients lacking the atypia on the peripheral blood smear or the corroborating evidence are considered to have erythrodermic CTCL.
TREATMENT AND PROGNOSIS
Compared with patients with patch- or plaque-stage MF, patients with SS have a markedly decreased 5-year survival rate of 33 percent. By the time the SS appears, there is very little normal immunity left. Indeed, Sézary's patients have died from infectious complications, not from progressive disease.