Central photopenic lesions on FDG-PET scan in a patient with peripheral T cell lymphoma.

Central necrosis in lymphoma lesions as demonstrated in [(18)F] fluoro-2-deoxyglucose positron emission tomography (FDG-PET) studies is a rare phenomenon, and the clinical significance of this observation has not been described in the literature. The role of FDG-PET in the management of peripheral T cell lymphoma (PTCL) is also still unclear at this time. We present a case of a patient newly diagnosed with PTCL who underwent both computed tomography (CT) and FDG-PET examinations prior to and following therapy. CT showed pulmonary cavitary lesions in both lungs, and PET demonstrated multiple large confluent masses with intense FDG uptake in the corresponding lung fields with central photopenia suggestive of necrosis. Post-treatment FDG-PET images showed a significant improvement in the previously described lesions with some residual, recurrent, and new lesions. Central necrosis shown by PET may be associated with the advanced stage of the disease and may have prognostic implications because of central necrosis caused by hypoxia.