An ectopic mediastinal parathyroid adenoma accurately located by a single-day imaging protocol of Tc-99m pertechnetate-MIBI subtraction scintigraphy and MIBI-SPECT-computed tomographic image fusion.

PURPOSE: Because ectopic parathyroid adenoma (PA) is a frequent cause of failed initial surgery, an imaging approach with accurate preoperative localization is recommended by some authors in patients with primary hyperparathyroidism (HPT).
METHODS: The authors describe a 52-year-old woman in whom primary HPT was diagnosed incidentally during a screening program for osteoporosis. The peculiarity of this case is that the patient was examined before operation in a single-day multimodal imaging protocol based on the combination of high-resolution cervical ultrasound, planar Tc-99m pertechnetate-MIBI scans, and an MIBI-SPECT-computed tomographic (CT) image fusion study. An ectopic PA was accurately located in the upper middle mediastinum, close to the lower margin of the sternal notch.
RESULTS: Guided by the MIBI-SPECT-CT fusion images, the surgeon performed a limited median sternotomy and easily removed the PA that was revealed before operation. To confirm the completeness of resection, a bilateral neck exploration was performed through the same incision, with identification of three normally sized parathyroid glands.
CONCLUSIONS: Our experience suggests the utility of multimodality imaging procedures for the accurate preoperative localization of PAs, particularly when they are present in ectopic mediastinal locations. Such procedures, including the MIBI-SPECT-CT image fusion study, can be performed in a single day.