Ectopic Parathyroid Adenoma on Pectoralis Major After Endoscopic Parathyroidectomy Revealed by 99mTc-MIBI SPECT/CT.

A 45-year-old woman, who had endoscopic parathyroidectomy 5 years ago for a right inferior parathyroid adenoma, underwent 99mTc-MIBI scan for the evaluation of recurrent parathyroidism. The images did not identify any abnormal uptake in the neck. Instead, an abnormal activity in the right upper chest wall was noted, which was located in a soft tissue nodule inseparable from the right pectoralis major muscle on SPECT/CT images. Pathology confirmed parathyroid tissue.