Although Anaplastic Large Cell Lymphomas (ALCL) carrying Anaplastic Lymphoma Kinase (ALK) have a relatively good prognosis, aggressive forms exist. We have identified a novel translocation, causing the fusion of the TRAF1 and ALK genes, in one patient who presented with a leukemic ALK+ ALCL (ALCL-11). To uncover the mechanisms leading to high-grade ALCL, we developed a human Patient Derived Tumorgraft (hPDT) line. Molecular characterization of primary and PDT cells demonstrated the activation of ALK and NFkB pathways. Genomic studies of ALCL-11 showed the TP53 loss and the in vivo subclonal expansion of lymphoma cells lacking PRDM1/Blimp-1 and carrying c-MYC gene amplification. The treatment with proteasome inhibitors of TRAF1-ALK cells led to down-regulation of p50/p52 and lymphoma growth inhibition. Moreover a NFkB gene set classifier stratified ALCL in distinct subsets with different clinical outcome. Although a selective ALK inhibitor (CEP28122) resulted in a significant clinical response of hPDT mice, nevertheless the disease could not be eradicated. These data indicate that the activation of NFkB signaling contributes to the neoplastic phenotype of TRAF1-ALK ALCL. ALCL hPDTs are invaluable tools to validate the role of druggable molecules, predict therapeutic responses and implement patient specific therapies.Leukemia accepted article preview online, 23 December 2014. doi:10.1038/leu.2014.347.