Quantitative metabolic PET imaging of a plasma cell granuloma.

We report a patient who underwent surgical resection of two lung nodules that proved to be recurrent plasma cell granuloma, also known as inflammatory pseudotumor. Prior to surgery, positron emission tomography (PET) was performed with 18F-labeled fluoro-2-deoxy-D-glucose (18FDG) and rubidium-82 (82Rb). The 18FDG PET scan revealed that the nodules corresponded to two areas of intense uptake. PET imaging with 82Rb, the marker of flow, also showed intense uptake. Thus, PET demonstrated both a high degree of metabolic activity and increased perfusion. These features suggest a lesion with high cellular activity rather than a simple reparative process. The true nature of this lesion remains unknown.