Mary K Debenedetti | PubMed Health

PubMed2005

Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A.

BACKGROUND: Medullary thyroid carcinoma is the most common cause of death in patients with multiple endocrine neoplasia (MEN) type 2A (MEN-2A) or type 2B or familial medullary thyroid carcinoma. We sought to determine whether total thyroidectomy in asymptomatic young members of kindreds with MEN-2A who had a mutated allele of the RET proto-oncogene could prevent or cure medullary thyroid carcinoma. METHODS: A total of 50 patients 19 years of age or younger who were consecutively identified through a genetic screening program as carriers of a RET mutation characteristic of MEN-2A underwent total thyroidectomy. Five to 10 years after the surgery, each patient was evaluated by physical examination and by determination of plasma calcitonin levels after stimulation with provocative agents. RESULTS: In 44 of the 50 patients, basal and stimulated plasma calcitonin levels were at or below the limits of detection of the assay (proportion, 0.88; 95 percent confidence interval, 0.76 to 0.95). Two patients had basal and stimulated plasma calcitonin levels above the normal range. Stimulated plasma calcitonin levels had increased but remained within the normal range in four patients. The data suggest that there was a lower incidence of persistent or recurrent disease in children who underwent total thyroidectomy before eight years of age and in children in whom there were no metastases to cervical lymph nodes. CONCLUSIONS: In this study, young patients identified by direct DNA analysis as carriers of a RET mutation characteristic of MEN-2A had no evidence of persistent or recurrent medullary thyroid carcinoma five or more years after total thyroidectomy. A longer period of evaluation will be necessary to confirm that they are cured.

Adolescent↗

PubMed2002

Recurrent or persistent hyperparathyroidism.

Approximately 90% of patients with primary hyperparathyroidism (PHPT) are cured by parathyroidectomy at the initial neck exploration. Those not cured either remain hypercalcemic in the immediate postoperative period or develop hypercalcemia after a long period of normocalcemia. Almost all cases of hypercalcemia after neck exploration for PHPT are evident early in the postoperative period and are caused either by an overlooked parathyroid adenoma or an incomplete resection of hyperplastic parathyroid tissue. Less commonly, the surgeon has failed to recognize, and adequately treat, parathyroid carcinoma, or the diagnosis of PHPT was incorrect and there is another cause of the hypercalcemia. A successful neck exploration for PHPT is primarily dependent on the experience of the operating surgeon, the anatomic location of the parathyroid glands, either in "normal" or "ectopic" sites, and the presence of a single enlarged parathyroid gland as opposed to multiglandular disease or parathyroid carcinoma. In cases where an enlarged parathyroid gland is not identified at operation, noninvasive or invasive radiographic imaging procedures are useful in localizing the gland. Currently, the most reliable and practical procedure is technetium 99m sestamibi scanning. This technique identifies an enlarged parathyroid gland in 65-80% of cases. Single photon emission computed tomography (SPECT) in association with sestamibi scanning increases the sensitivity of the procedure to 85%. These imaging procedures are least reliable in patients with multiglandular disease. Ultrasound and computed tomographic scanning are less sensitive; however, they are commonly used as confirmatory tests in association with sestamibi scanning. When noninvasive imaging procedures fail to identify an enlarged parathyroid gland, invasive procedures, such as selective arteriography, are performed. Whereas invasive procedures are useful, they are associated with significant morbidity. Reoperations for persistent or recurrent hyperparathyroidism, compared with the initial operations, are associated with higher complication rates. In 90% of cases, the abnormal pathology can be reached through a cervical incision. The success rate of the reoperation depends primarily on the results of the localization procedure and whether the patient has a single enlarged parathyroid gland or multiglandular disease. Resection of a single enlarged gland is curative in virtually all patients. If, however, the patient has multiple gland disease, the operation is successful less often, especially in those with certain familial endocrinopathies.

Choristoma↗