FDG-PET in T-cell and NK-cell neoplasms

Background: A growing number of studies demonstrate the utility of (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of maligr ant lymphoma. The results of FDG-PET, however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms. Patients and methods: We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4). Results: FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%. Conclusion: T/NK-cell neoplasms incorporated in his study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.