We report benign axillary tracer uptake on F-18 FDG PET scans in patients with rheumatoid arthritis.
Axillary tracer uptake was observed in 9 patients who were undergoing PET for staging or restaging of malignancy. The uptake was not in a pattern that would be expected for the patients' known malignancies. Additional clinical information was obtained and quantitation of tracer uptake in the upper extremities and axillae was performed.
All 9 patients were found to have rheumatoid arthritis. Increased axillary tracer uptake was bilateral in 7 patients and unilateral in 2 patients. In 8 of the patients the wrists were included in the field of view and showed elevated FDG uptake. On follow-up there was no evidence of malignancy in any of the axillary foci.
Increased axillary tracer uptake on F-18 FDG PET scans can be seen in conjunction with increased uptake in the wrists in patients with rheumatoid arthritis, and is not necessarily an indication of malignancy.