Invasive Testing for Preoperative Localization of Parathyroid Tumors

The identification of parathyroid tumor(s) in patients with persistent/recurrent primary hyperparathyroidism (PHPT) is critical for a successful reoperative surgery. If noninvasive studies (ultrasound, computed tomography, magnetic resonance imaging, sestamibi) fail to conclusively localize the tumor, invasive procedures (arteriography and selective venous sampling) are performed.

To describe our experience with invasive studies for parathyroid tumor localization and provide follow-up data on selective arterial hypocalcemic stimulation with central venous sampling, a technique developed at our center.

We identified patients who underwent preoperative invasive testing for localization of parathyroid tumor from 1991 to 2020. The result of each invasive localization study [arteriogram, hypocalcemic stimulation and selective venous sampling (SVS)] was categorized as true-positive, false-positive, and false-negative based on histology and biochemical outcome.

Ninety-four patients with 96 tumor occurrences underwent invasive testing for parathyroid tumor localization. Arteriogram, hypocalcemic stimulation, and SVS accurately localized the tumor in 47 of 94 (50%), 56 of 93 (60%), and 51 of 62 (82%) tumors, respectively. Hypocalcemic stimulation was more likely to correctly localize the tumor when arteriogram showed a blush [37 of 50 (74%) vs 19 of 43 (44%), P = .01]. When both arteriogram and hypocalcemic stimulation yielded concordant positive findings, SVS did not change management in the 18 cases in which all 3 were performed. Twelve patients remained with persistent PHPT; all had recurrent disease with multiple affected glands.

Hypocalcemic stimulation is a useful adjunct in patients with PHPT who require invasive localization and can obviate the need for SVS. Clinical Trial number: NCT04969926.