Primary hyperparathyroidism during pregnancy: ultrasound as an accurate preoperative localization imaging modality.

Background: Accurate identification of parathyroid lesions in primary hyperparathyroidism (PHPT) patients is essential for minimally invasive surgery during pregnancy.

Materials and methods: Patients who were diagnosed with PHPT during pregnancy and who had undergone surgical treatment between January 2005 and September 2023 were retrospectively included. Demographic and clinical characteristics and preoperative parathyroid ultrasound (US) and technetium-99m sestamibi (^99mTc-MIBI) scintigraphy results were collected. Histopathologic examinations were conducted for all lesions removed during neck surgery, and the results were considered as the reference standard.

Results: A total of 19 pregnant patients with PHPT who had undergone parathyroidectomy were retrospectively included in the study. The median age was 30 years. Sixteen (16/19, 84.2%) patients had single-gland disease and three (15.8%) had two lesions. Three patients were confirmed as multiple endocrine neoplasia type 1. The median size of all lesions was 1.8 cm (0.6-7.5 cm). All patients had undergone US examination, and eight patients had ^99mTc-MIBI scintigraphy. A total of 21 lesions were found on US. The diagnostic sensitivity of the US was 95.45% per lesion and 100% per patient. One lesion, with a maximum diameter of 0.6 cm, was missed preoperatively by either US or ^99mTc-MIBI scintigraphy. Nine patients had surgery in the second trimester and 88.89% of them had a full-term pregnancy after surgery. There were no complications in the newborns.

Conclusions: In pregnant PHPT patients, US achieved high sensitivity for preoperative lesion localization. Surgery during the second trimester after accurately localizing the lesion(s) by US improved the patients' pregnancy outcomes.