99mTc-Sestamibi Scintigraphy Reveals Parathyroid Adenoma Masquerading as Esophageal Diverticulum

A 74-year-old woman with primary hyperparathyroidism diagnosed from routine laboratory tests described symptoms of fatigue and difficulty with concentration. During surgical consultation, the cervical and thoracic spine MRI scans from the preceding 10-year period, performed for relapsing-remitting multiple sclerosis, were reviewed. In this clinical context, the slowly enlarging left upper paraesophageal lesion, reported as a lateral proximal esophageal (Killian-Jamieson) diverticulum, was reevaluated for a potential parathyroid adenoma. 99mTc-sestamibi SPECT/CT demonstrated focal uptake in the paraesophageal lesion with surgical resection, confirming it to be a large parathyroid adenoma.