Imaging findings in paediatric non-Hodgkin lymphoma: a pictorial review

Non-Hodgkin lymphomas (NHL) are a heterogeneous group of lymphoid malignancies, whose subtypes vary regarding radiological presentation, clinical course, and prognosis. Imaging plays a major role in initial diagnosis, staging, assessment of treatment response, and complications. Early diagnosis and treatment of paediatric NHL are crucial, due to the highly aggressive nature of the majority of subtypes in paediatric patients. Unlike adults, low-grade lymphomas are seldomly seen in children. Initial correct diagnosis can be challenging given the predominantly extranodal origin with subsequent overlap with other diseases. In this pictorial review, we describe the imaging features at presentation of the most common NHL subtypes in children. We highlight certain characteristics that can support clinical decision-making, especially relevant in scenarios that require prompt management. Furthermore, the recently introduced classification and staging criteria are briefly discussed.