SPECT-CT in the localization of an ectopic retropharyngeal parathyroid adenoma as a cause for persistent primary hyperparathyroidism.

A common cause for surgical failure of primary hyperparathyroidism (pHPT) is the non-detection of an ectopic adenoma during the intervention. We present a case of a patient with pHPT in whom an ectopic gland was found in the right retropharyngeal space by means of a double phase (99m)Tc-methoxy-isobutyl-isonitrile ((99m)Tc-MIBI) scintigraphy and early SPECT-CT after several surgeries and imaging tests. The addition of a tomography to the planar scintigraphy increases its sensitivity and improves pathological parathyroid glands localization. The hybrid imaging is sometimes essential to obtain surgical success, as in the case of ectopic adenomas.