Mycosis Fungoides is a rare, incurable and potentially lethal primary cutaneous T-cell lymphoma. The diagnosis is often protracted for several years due to clinical and histopathological resemblance with benign dermatosis. One third of patients will evolve an aggressive course and succumb to the disease. Our group has previously identified diagnostic and prognostic molecular classifiers, and this study seeks to establish a combined molecular signature of mRNA and miRNA to both facilitate early diagnosis and identify patients at risk for aggressive disease at an early disease stage, where the patients still are eligible for therapeutic interventions and the disease progression can be stalled. To date, this is the largest international study on diagnostic and prognostic markers in Mycosis Fungoides worldwide.