Axillary lymph node visualization on F-18 FDG PET body scans in patients with rheumatoid arthritis

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.