18F-FDG PET/CT Evaluation of Lymphoma with Renal Involvement: Comparison with Renal Carcinoma

Abstract

Lymphoma can arise at any anatomic site, but it is rare to find kidney involvement. The aim of this study was to assess the role of F-flourodeoxyglucose (F-FDG) positron emission tomography (PET)/computed tomography (CT) in detecting lymphoma with renal involvement. Reports of such use of F-FDG PET/CT are limited. Twelve lymphoma patients with renal involvement and 12 renal carcinoma patients were studied with F-FDG PET/CT. Intense F-FDG uptake, suggestive of positivity, was measured in mean standardized uptake values (standardized uptake values [SUV] mean). The results of PET/CT were validated by bone marrow, biopsy tissue and/or surgery. F-FDG PET/CT detected lymphoma with renal involvement lesions or renal carcinoma lesions in at least one site in the 24 patients. F-FDG uptake by the lymphoma lesions was much higher than the F-FDG uptake by the renal clear cell carcinomas (SUV mean 6.37 +/- 2.28 vs 2.58 +/- 0.62), and similar to that of renal cell carcinoma and renal collecting duct carcinoma (SUV mean 6.37 +/- 2.28 vs 6.27 +/- 1.15). There were dissimilar morphological changes in the homologous CT. Differing from renal cancer, lymphoma in the spleen, uterus, and bone marrow can easily be diagnosed by F-FDG PET/CT. The lesions of lymphoma with renal involvement, and especially those of primary renal lymphoma, are F-FDG avid. PET/CT appears to be useful in comparing these lesions with those of renal carcinoma, especially for primary renal lymphoma.