Utility of 18F-FDG PET/CT for staging NK/T-cell lymphomas.

PURPOSE: Extranodal natural killer (NK)/T-cell lymphoma is a rare neoplasm and limited data has reported regarding the utilization of fluorine-18, fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) in this disease. The aim of this study was to assess the role of F-FDG PET/CT in the staging of NK/T-cell lymphomas.

PATIENTS AND METHODS: Thirteen newly diagnosed and two recurrent patients with NK/T-cell lymphoma who received F-FDG PET/CT were studied. The lesion with intense F-FDG uptake was suggested as the positive and was measured using maximal standardized uptake values. The results of PET/CT were compared with the conventional staging examinations.

RESULTS: F-FDG PET/CT detected nasal or extranasal lymphoma lesions in at least one site in all of the 15 patients. There was no significant difference of F-FDG uptake in lesions between patients with stage I-II disease and those with stage III-IV disease (maximal standardized uptake values 8.44+/-5.56 vs. 10.32+/-7.80; t=0.757, P>0.05). In two patients with an indeterminate diagnosis, the diagnosis of NK/T-cell lymphomas was established by biopsy guided by PET/CT and the status of stage IV was correctly identified. In 13 patients with definite diagnosis, the stage of disease was changed in six patients on the basis of F-FDG PET/CT. Two patients were down staged, and four patients upstaged.

CONCLUSION: The lesions of the NK/T-cell lymphoma are F-FDG avid and PET/CT seems to be useful in the staging of this disease.