A 9-year-old boy presented with fever, lymphadenopathy, lung nodules and skin lesions. ALK-positive anaplastic large cell lymphoma (ALCL) was diagnosed from a skin biopsy. He showed minimal disease dissemination in his peripheral blood which persisted after the first course chemotherapy. Two months after treatment with 6 courses of polychemotherapy according to ALCL99 he suffers a relapse. A second remission was obtained by an ALK inhibitor. Currently, allogeneic hematopoietic stem cell transplantation (SCT) for consolidation is discussed by the treating physicians and the family (see Fig. 1).

This review focusses on the diagnosis and treatment of ALK-positive anaplastic large cell lymphoma in children and adolescents.

ALCL was first described in 1985 as a CD30-positive mature T cell lymphoma [1]. ALCL is a rare disease with about 10–15% of all childhood and adolescent NHL cases and an incidence of about 1.2/106/year [2,3]. In children and adolescents, about 95% of cases are ALK-positive ALCL [4].

The molecular basis and clinical characteristics of ALK-positive ALCL were described in the early 1990s. During the following years the molecular pathogenesis was unravelled [[5], [6], [7]], the ALK1-antibody detected which facilitated diagnostics, and the clinical characteristics described in national cohort studies [[8], [9], [10]]. In the 2000s the role of immunology in tumour biology and control was detected [11], targeted therapeutics developed [12,13] and multinational clinical trials were performed [4,[12], [13], [14], [15]]. All this not only led to the implementation of ALK-positive as a separate entity in the WHO classification [16], but also to an array of successful early clinical trials [[17], [18], [19], [20], [21]] testing targeted drugs during the last 10 years. These rapid developments form the basis for a future outlook on chemotherapy-free therapeutic strategies.