Endocrine Abstracts

Patients with primary hyperparathyroidism (PHPT) undergo parathyroid ultrasound, Tc-99m sestamibi scan or MRI to localize hyperfunctioning parathyroid gland(s). When scans are negative or discordant we perform parathyroid hormone selective venous sampling (PTHSVS).

We report the results of 18 patients (four males, 14 females, average age 58.7) with PHPT, who underwent PTHSVS followed by either focused parathyroidectomy (FP) or bilateral neck exploration (BNE) in years 2006–2013.

All patients had both parathyroid ultrasound and Tc-99m sestamibi scans. Parathyroid ultrasound showed lateralisation in 27.8% (16.67% possible and 11.1% confident) and Tc-99m sestamibi showed lateralisation in 33.3% (27.8% possible and 5.56% confident). In 11.1% of patients lateralisation was present on both scans but results were discordant.

On average during the PTHSVS procedure samples for PTH levels were obtained from 10.78 sites. All procedures were successful.

PTHSVS showed lateralisation in 12 patients (66.7%). Following the results of PTHSVS ten patients underwent FP, two had BNE. Histopathological results confirmed nine adenomas (75% true positive). In remaining three cases (25% false positive) there was one confirmed hyperplasia and one positive PTHSVS is thought likely to contain a spurious PTH result.

The average ratio between the site of highest PTH level and level of PTH in inferior vena cava was 7.37 (2.61–19.38) in patients with lateralisation.

In six patients with no lateralisation on PTHSVS, three had BNE, and three FP. Histopathological report in five patients confirmed existence of parathyroid adenoma (83.3% false negative). One patient had hyperplasia (16.7% true negative).

Seven out of ten patients who had FP were cured during first operation. Three patients required reoperation, one of them was not cured due to anatomical localization of the adenoma.

Our report suggests that PTHSVS is a helpful diagnostic adjunct in localization of hyperfunctioning parathyroid gland(s). Positive PTHSVS increases the surgeon’s confidence in choosing a less invasive procedure.