Para-hyoid ectopic parathyroid adenoma localized by Tc-99m MIBI SPECT.

A 64-year-old woman with a history of I-131 ablation for Graves hyperthyroidism and bilateral parathyroid exploration with resection of a left inferior parathyroid adenoma presented 2 years after surgery with marked fatigue, irritability, and joint pain. Laboratory testing revealed an elevated calcium and parathyroid hormone levels suspicious for hyperparathyroidism. The ultrasound indicated no evidence of a parathyroid adenoma. Tc-99m-MIBI SPECT demonstrated a focus of uptake posteroinferior to the right submandibular gland, suspicious for a parathyroid adenoma. Repeat ultrasound and CT confirmed the presence of a para-hyoid adenoma inferior to the right submandibular gland.