Bilateral neck exploration in patients with primary hyperparathyroidism and discordant imaging results: a single-centre study

Introduction: Focused parathyroidectomy is the treatment of choice for patients with concordant positive imaging. Bilateral cervical exploration is performed for cases with discordant imaging, yet more than 70% of those cases are the result of a single-gland disease. As focused parathyroidectomy is generally costless and harmless, for cases with discordant imaging, we tried to determine whether preoperative characteristics can lead to a diagnosis of single-gland disease. Methods: This study included 182 patients treated for primary hyperparathyroidism by bilateral exploration from 2009 to 2012 at La Timone Hospital, Marseille, France. We classified patients based on preoperative images and pathological results (single-gland or multiglandular disease). We then compared the demographical, laboratory and imaging results. We also asked a senior nuclear medicine practitioner who was blind to the ultrasound and pathological results to perform a second reading. Results: Of the total number of patients, 15.4% had negative, 54.4% discordant and 30.2% concordant imaging. After reviewing the scintigraphy results, 8% of the cases with discordant imaging would have been classified as concordant with ultrasound. Subtraction scintigraphy obtained better results than dual-phase scintigraphy (concordance with ultrasound in 50 vs 31% with classical scintigraphy). For the cases of discordant imaging, no predictive factors of single-gland disease could be identified. Ultrasound and scintigraphy were similarly effective in determining the correct location of the abnormal gland. Conclusion: Discordant results of preoperative imaging modalities do not discriminate between uniglandular and multiglandular diseases in hyperparathyroidism. Diagnostic differentiation between the different causes of hyperparathyroidism requires improvements in imaging techniques and might benefit from subtraction scintigraphy.