Background: Sezary syndrome (SS) is characterized by erythroderma with leukemic involvement. In atypical SS, leukemic involvement is present without erythroderma. Little is known about the presentation, prognosis, and outcome in these patients. Objective: We sought to describe our experience with patients with SS without erythroderma. Methods: We retrospectively identified patients with SS, but without erythroderma, at Mayo Clinic from 1976 to 2010. Patients all met criteria for high blood tumor burden. Their clinical characteristics, disease course, and prognosis were reviewed and compared with a previously described cohort of 176 patients with SS from this institution. Results: Among 16 patients identified, all had cutaneous findings consistent with cutaneous T-cell lymphoma, most commonly erythematous patches (n = 6) and plaques (n = 12). All 16 patients were deceased at the time of the study. Median time from diagnosis of SS without erythroderma to the date of death was 3.6 years (range, 0.5-8.7 years). Survival was not different between patients with SS with and without erythroderma (hazard ratio 1.58; 95% confidence interval 0.94-2.66; P =.08). Limitations: This was a single-institution retrospective study. Conclusion: Leukemic involvement may confer shortened survival in patients with SS, because the presence of erythroderma did not affect survival. These atypical cases could potentially be more accurately described using the TNMB classification.