Parathyroid surgical failures with sufficient decline of intraoperative parathyroid hormone levels: unobserved multiple endocrine neoplasia as an explanation.

HYPOTHESIS: A sufficient decline in levels of parathyroid hormone measured intraoperatively (ioPTH) precludes early and late surgical failures.

DESIGN

A case series of consecutive patients undergoing parathyroidectomy with ioPTH measurement.

SETTING

A university hospital.

PATIENTS AND INTERVENTION: Two hundred sixty-nine consecutive patients with sporadic primary hyperparathyroidism who underwent first-time parathyroid surgery with ioPTH measurement were followed up for as long as 10 years after surgery. Data on all patients have been collected in a prospective database.

MAIN OUTCOME MEASURES: Surgical failures up to 10 years after parathyroid surgery.

RESULTS

With an average follow-up of 3.6 years (range, 6-120 months), the overall cure rate was 96%. The ioPTH level correctly predicted long-term outcome in 248 (92%) of 269 patients. Six patients had a false-positive ioPTH finding. Five of these patients were found to have germline mutations in the gene for multiple endocrine neoplasia. The remaining patient has not undergone genetic testing. The mutations have rarely (n = 1) or never (n = 4) been described before, to our knowledge.

CONCLUSIONS

Intraoperative measurement of PTH level has a high overall accuracy with a mean follow-up of 3.6 years. However, among the late surgical failures with false-positive ioPTH findings, overlooked mutations in the multiple endocrine neoplasia gene should be suspected, and therefore genetic analyses in these patients are of great importance.