Incidental Finding of Moderna COVID-19 Vaccination-Related Axillary Lymphadenopathy on 201Tl Myocardial Perfusion Imaging.

We presented here a 71-year-old man with a history of thyroid cancer post total thyroidectomy and 131I ablation and right renal cell carcinoma post right partial nephrectomy. He reported persistent chest tightness and pain after the first dose of the Moderna COVID-19 (mRNA-1273) vaccine. Thus, coronary heart disease was suspected, and the patient was referred for MPI (myocardial perfusion imaging). Focal 201Tl uptake in the left axillary region was found incidentally on MPI, and SPECT/CT revealed enlarged benign-looking lymph nodes. The diagnostic is in favor of reactive hyperplasia after the intramuscular injection of vaccine into left deltoid muscle.