Clinical and Histological Characteristics of Mycosis Fungoides and Sézary Syndrome: A Retrospective, Single-centre Study of 43 Patients from Eastern Denmark.

Diagnosis of mycosis fungoides and Sézary syndrome can be very challenging. Clinical and histopathological data for patients with mycosis fungoides and Sézary syndrome in Denmark are limited. A retrospective study was performed in Region Zealand, Denmark from 1990 to 2016. A total of 43 patients with mycosis fungoides or Sézary syndrome were identified during the period. At the time of diagnosis the patients' mean age was 64.3 years and 74.5% had early-stage (≤IIA) disease. The mean time from onset of skin disease to diagnosis was 4.4 years. Surprisingly, 43% progressed to a higher disease stage, and risk of disease progression was higher for stage IB than IA (p = 0.01). All cases displayed some degree of epidermotropism and the infiltrates consisted of pleomorphic lymphocytes with a T-helper (CD4+/CD8-) phenotype. This study describes, for the first time, all aspects of clinical and histopathological findings in patients with mycosis fungoides and Sézary syndrome in a well-characterized Danish cohort.