Anaplastic large cell lymphomas (ALCLs) are rare CD30+ peripheral T-cell lymphomas (PTCLs) classified according to the expression of the anaplastic lymphoma kinase (ALK+) protein or not (ALK-). We have analysed the outcome and risk factors for survival in a population-based bi-national cohort of patients with systemic ALK+ ALCL. A total of 122 adult (=18 years) patients diagnosed with ALK+ ALCL between 2000 and 2010 were identified from the Danish and Swedish lymphoma registries, representing 0·4% of all lymphomas. The median age of the cohort was 40 years (range 18-85). The 5-year overall survival and progression-free survival (PFS) was 78% and 64%, respectively. Age was strongly associated with outcome, and only bone marrow (BM) involvement was independently associated with poorer PFS in multivariate analysis (Hazard Ratio [HR] = 8·57, P
