Incidentalomas of the parathyroid gland: multiple presentations, variable function, and review of the literature.

OBJECTIVE: To present a series of cases of parathyroid incidentalomas and review the related medical literature. METHODS: The medical records of all patients of one surgeon who underwent unplanned removal of enlarged parathyroid glands found either during a surgical procedure performed for indications other than hyperparathyroidism or by ultrasonography of the thyroid gland between September 1989 and December 2003 were reviewed retrospectively. Clinical and laboratory data-- especially serum calcium and parathyroid hormone (PTH) levels--as well as information on postoperative parathyroid function are reported. RESULTS: Among 421 patients (355 who underwent thyroidectomy and 66 who underwent transhiatal esophagectomy), 5 cases of parathyroid incidentalomas (1.2%) were identified. These incidental parathyroid adenomas were found during thyroidectomy for thyroid cancer in two patients, during esophagectomy for esophageal cancer in one patient (the first such reported case), and during ultrasonography of the neck for evaluation of thyroid nodules in two patients. Of the five patients, three had a normal and one had a slightly increased serum calcium concentration preoperatively; the serum calcium level was not determined preoperatively in the other patient. In one patient in whom intraoperative PTH level was determined both before and after resection of a large parathyroid adenoma, the initially high PTH value (180 pg/mL) declined to the normal range (48.2 pg/mL). In another patient, bone densitometry 9 months postoperatively showed an 8% increase in T-score for the lumbar spine and a 3.9% increase in T-score at the femoral neck, in comparison with bone density tests done 3 months preoperatively. No patient had persistent or recurrent hyperparathyroidism or hypoparathyroidism postoperatively or during subsequent follow-up. CONCLUSION: Incidental identification of enlarged parathyroid glands during a neck surgical procedure is not common but does occur. Intraoperative and postoperative measurements of serum calcium and PTH along with postoperative bone density testing can help determine whether such parathyroid incidentalomas are functional. These enlarged parathyroid glands should be removed.