The value of intraoperative parathyroid hormone assay in the surgery of mediastinal ectopic parathyroid adenoma (A case series)

Abstract

Background and aims Ectopic parathyroid adenoma is a rare entity. Its clinical management is challenging due to varying locations in the mediastinum. The aim of our study is to report our experience about the preoperative localization of the ectopic parathyroid adenoma and to emphasize the major role of the intraoperative parathyroid hormone assay in such circumstances. Methods It is a monocentric, retrospective study about patients diagnosed with EPA (ectopic parathyroid adenoma) from January 2015 to December 2016. Clinical aspects, preoperative management as well as the surgical procedures have been analyzed. Results There were 7 women, with an average age of 59.14 years. Six patients presented with biological disorders of the phosphocalcic metabolism such as spontaneous bone fracture and recurrent renal lithiasis. In one case, EPA was discovered in the setting of malignant hypercalcemia. The topographic preoperative assessment with a cervicothoracic CT (computed tomography) showed spontaneously hyperdense tissular masses of variable localizations in the mediastinum. A Tc-99 m (99mTc - MIBI) scintigraphy was performed in 5 patients and showed uptake in all cases. We performed cervicotomy in 1 case, manubriotomy in 2 patients, neck manubriotomy in 2 cases, total vertical sternotomy in 1 case, and posterolateral thoracotomy in 1 patient. The lesion was localized in the mediastinum in 1 patient in the perithymic fat in 1 case; EPA was laterotracheal in 1 case, retro tracheal in 1 case, intra-thymic in 2 cases, inter-jugulo-carotidian with contact with the left subclavial artery in 1 case, and anterior mediastinal in 1 patient. The 1-h after-parathormonemia following removal of the surgical specimens showed a decrease value of 45 and 80% of the baseline value. No surgical morbidity was noted after an average follow-up of 7.9 months (range of 5–18 months). Conclusion The preoperative topographic diagnosis of ectopic parathyroid adenoma is challenging for the surgeon despite progress in the morphological assessment. The intraoperative parathyroid hormone assay is a valuable tool for an appropriate surgical management.

Localization of Ectopic Mediastinal Parathyroid Adenomas Using Indigo Carmine Injection for Surgical Management: A Preliminary Report

“…The EPAs have a variable incidence according to many studies ( 3 , 14 , 15 ). Phitayakorn et al ( 16 ), in a series of 231 patients who underwent surgery for hyperparathyroidism, reported that 16% were ectopic lesions, among which 3% were intra-thymic ( 16 ).…”

“…The caudal parathyroid glands and thymus are embryologically-derived from the third branchial pouch before migration to the cervical and mediastinal levels, respectively ( 17 ). This migration may explain the possibility of supernumerary parathyroid and ectopic glands, especially in the thoracic cavity ( 3 ). The patients with EPA are among those with PHPT diagnosed based on blood tests.…”

“…Thus, to support the diagnosis, 99m Tc-MIBI scintigraphy was performed in 8 patients and showed uptake in 6 patients. Indeed, sestamibi scintigraphy is currently considered the technique of choice because it has a sensitivity of approximately 95% and better image quality than a CT scan with a lower radiation exposure ( 3 , 18 , 19 ). According to Rousseau et al ( 1 ), in the presence of a parathyroid adenoma, surgical resection of hyperfunctioning tissue is the gold standard.…”

“…According to Rousseau et al ( 1 ), in the presence of a parathyroid adenoma, surgical resection of hyperfunctioning tissue is the gold standard. The current trend is to offer surgery to all patients in whom the diagnosis of PHPT is made, which includes asymptomatic patents regardless of age ( 1 , 3 , 20 , 21 ). Table 2 shows the indications for surgery in the treatment of PHPT based on the 2014 guidelines for the management of asymptomatic PHPT ( 22 ).…”

“…The most frequent cause of PHPT is a benign solitary parathyroid adenoma, which occurs in 80–90% of patients ( 1 , 2 ). An ectopic focus is demonstrated in up to 22% of the patients; the prevalence is even higher in the patients who undergo redo surgery ( 3 , 4 ). Surgery is the only definitive cure for PHPT and is indicated in all symptomatic patients, as well as a defined subgroup of asymptomatic patients ( 2 , 5 ).…”