Concomitant Thyroid Cancer in Patients with Multiple Endocrine Neoplasia Type 1 Undergoing Surgery for Primary Hyperparathyroidism

Background: Compared to those with sporadic primary hyperparathyroidism (SPHP), multiple endocrine neoplasia type 1 (MEN1) patients with primary hyperparathyroidism (MPHP) typically require more extensive dissection and have higher recurrence rates. Little is known about the risk of concomitant thyroid cancer in either setting. This study aimed to determine the rates and characteristics of thyroid cancer for MPHP versus SPHP patients undergoing parathyroidectomy. Methods: Patients with MPHP (diagnosed by clinical and/or genetic criteria) or SPHP who had initial or reoperative parathyroid exploration from 1967 to 2014 were identified via a prospective database. The thyroid cancer-specific data for MPHP patients ( n = 29) were compared to a selected 2:1 age- and sex-matched SPHP cohort ( n = 58) who all had concurrent thyroidectomy for any reason. Clinically significant thyroid cancer was defined as >1 cm in diameter. Results: In the MPHP group, 24/29 (83%) thyroidectomies were preoperatively unplanned versus 20/58 (34%) in the SPHP matched cohort ( p