Pediatric anaplastic large cell lymphoma presenting as generalized lymphadenopathy

Because a finding of generalized lymphadenopathy can be associated with such a wide range of diseases and conditions, determining its cause can sometimes be challenging. Infectious causes are the most common; however, it is important also to consider other entities in the workup. Here we present the case of a 3-year-old girl with generalized lymphadenopathy and fever, in whom the cause of the symptoms was initially thought to be infectious. Ultimately, however, anaplastic large cell lymphoma (ALCL) was diagnosed. Using this case as a backdrop, we discuss the wide range of systemic illnesses that the differential diagnosis of generalized lymphadenopathy encompasses--including infectious, autoimmune, and oncological disorders. We discuss the different findings typically seen in the various entities that figure prominently in the differential, and we outline investigations that can help narrow it. Finally, we present an overview of ALCL, one of the more rare pediatric malignancies.