Changes in the pathophysiology of primary hyperparathyroidism and analysis of postoperative recurrence cases at a regional core hospital in Japan: experience of 35 years in Shinshu University Hospital.

BACKGROUND

Since reoperation for recurrent primary hyperparathyroidism (PHPT) increases the risk of complications, such as recurrent laryngeal nerve palsy, it is vital to prevent recurrence as much as possible when performing the initial surgery. Therefore, we retrospectively analyzed the PHPT cases at Shinshu University Hospital from 1986 to 2020 for changes in the characteristics of PHPT over time and features of the recurrent cases to establish treatment strategies to prevent a postoperative recurrence.

METHODS

Hereditary PHPT was diagnosed through endocrinological tests, systemic imaging, and/or genetic testing. Localization of swollen parathyroid glands was identified through neck ultrasonography (US), contrast-enhanced computed tomography, magnetic resonance imaging (MRI), and 99mTc-sestamibi scintigraphy.

RESULTS

Among the 536 patients with PHPT (374 women and 162 men) with a mean age of 56.9±13.6 years, 90 (16.8%) had hereditary PHPT, while the other 446 (83.2%) had sporadic PHPT. Overall, 314 (58.6%) patients were asymptomatic, whereas 132 (24.6%) had symptoms related to PHPT. Asymptomatic PHPT was significantly more prevalent after 2001 (81.8%) than before 2001 (51.2%) (P<0.01), although the number of PHPT cases increased during the last decade. Resection of an enlarged parathyroid gland alone was performed for sporadic PHPT, while focused parathyroidectomy was performed after 2001. Total parathyroidectomy (TPTx) with autotransplantation was performed in patients with hereditary PHPT. In addition, the intraoperative rapid pathological diagnosis of the resected gland throughout the period and intraoperative serum intact parathyroid hormone (PTH) measurement from 2014 were used. Overall, 11 patients with hereditary PHPT (2.1%) developed recurrence. A recurrent parathyroid gland was identified in 10 of 11 cases through 99mTc-sestamibi scintigraphy.

CONCLUSIONS

Although the incidence of asymptomatic PHPT has been increasing recently, focused parathyroidectomy is considered an appropriate procedure for sporadic PHPT that has been carefully examined preoperatively. Therefore, in the future, it will be necessary to conduct genetic testing for sporadic PHPT cases as much as possible to accurately diagnose the disease type and decide on a treatment strategy.