Present role and future perspective of PET-CT in marginal zone lymphoma

The classification of the marginal zone lymphoma (MZL) among the ‘non-FDG avid’ lymphomas has discouraged the routine use of metabolic imaging in the evaluation of patients affected by this subtype of non-Hodgkin lymphoma. Nevertheless, recent data demonstrated that despite a significant heterogeneity due to different factors (location of the disease, morphological appearance and histological features of the main lesion) most of MZL lesions are detected by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), particularly in splenic and nodal MZL. The higher detection rate of the metabolic imaging with respect to the conventional radiological work-up may improve the accuracy of the MZL staging, mainly due to upstaging, in a significant number of patients, although the impact of this staging improvement on the management of the patients has not been measured yet. Preliminary promising results seem to indicate the potential usefulness of 18F-FDG PET as marker of treatment response, though its prognostic value remains uncertain. The role of the metabolic imaging in the clinical management of MZL is still an open question, needing more extensive studies including larger cohorts of patients, to be fully