Non-Hodgkin lymphoma dominated by multiple organ extranodal disease revealed on FDG PET/CT.

The definition of primary extranodal lymphoma is rather controversial and often complicated by the variety of lymphoma types. Here we describe FDG PET/CT findings in 3 pediatric patients with diffuse large B-cell non-Hodgkin lymphomas dominated by extranodal lesions involving multiple organs. Lymphomas arising primarily in extranodal sites can present significant diagnostic challenges due to their morphological diversity and lack of uniformity in histopathological classification.