FDG PET/CT Findings in a Localized Reactive Lymphoid Hyperplasia of the Spleen

A 38-year-old man with sigmoid colon cancer underwent a preoperative contrast-enhanced CT which incidentally revealed a modestly enhancing splenic mass. FDG PET/CT showed mildly increased uptake in the splenic lesion in contrast to prominently increased uptake in the colonic tumor. In addition, the splenic mass demonstrated only slightly increased signal intensity in diffusion-weighted MRI, suggesting low probability of metastasis. Splenectomy nonetheless was performed at surgery of the colon cancer. The histopathologic examination showed aggregated lymphoid follicles with germinal centers in the splenic lesion and made the diagnosis of localized reactive lymphoid hyperplasia a rare benign lymphoid tumor.