Mediastinal parathyroid localization: possible pitfall in technetium-thallium subtraction scintigraphy.

Two cases of mediastinal localization of parathyroid adenoma are presented, in which technetium-thallium subtraction scintigraphy yielded a positive result. Both patients had already undergone a negative surgical neck exploration. We suggest that, in case of negative subtraction scintigraphy and negative surgical exploration in proven primary hyperparathyroidism, subtraction scintigraphy should be repeated with emphasis on the superior mediastinum, and in all cases, the use of a non-zoom, large field of few procedure is recommended for technetium-thallium subtraction scintigraphy.