Multimodality Evaluation of Persistent Hyperparathyroidism in a Rare Case of Ectopic Submandibular Parathyroid Adenoma

A 53-year-old woman of primary hyperparathyroidism with both ultrasound neck examination and planar 99m Tc-MIBI scan being negative revealed a tracer-avid focus in the left submandibular region in early (15 minutes postinjection) 99m Tc-MIBI SPECT/CT views, raising a suspicion of rare ectopic parathyroid adenoma. This finding was correlated on 4D-CT and confirmed on histopathology following surgical excision. Submandibular region is an unusual location for ectopic parathyroid adenoma. Nevertheless, high degree of suspicion with utilization of multimodality imaging including 99m Tc MIBI-SPECT/CT and 4D-CT improves preoperative detection of parathyroid adenoma at rare ectopic sites as seen in this case of persistent hyperparathyroidism.