Papillary carcinoma in thyroglossal duct cyst.

OBJECTIVE: To report the management and outcome of three cases of papillary carcinoma (PC) in thyroglossal duct cysts (TGCs). METHODS: We present case reports of one female and two male patients between the ages of 22 and 46 years who had TGCs. In addition, we discuss the theories about the pathogenesis of TGC carcinoma (de novo versus metastatic lesions). RESULTS: In all three patients, we found a TGC that contained a vegetating mass. Subsequent pathologic examination revealed the presence of a PC. All patients underwent total thyroidectomy, and two of them concurrently had PC in the thyroid gland. Besides the PC in the TGC, the first patient had a "cold" scintigraphic thyroid nodule that was also a PC, whereas the second patient had a thyroid microcarcinoma that had not been detected before surgical intervention. The third patient did not have carcinoma of the thyroid, but the histologic pattern of the gland resembled that observed in de Quervain's disease. We interpreted this finding as "palpation thyroiditis." The patients received postoperative 131I and suppressive therapy with levothyroxine. During a follow-up period of 2 to 12 years (mean, 5.8), we found no recurrence of the disease, and serum thyroglobulin remained undetectable in all cases. CONCLUSION: Although use of total thyroidectomy followed by radioiodine therapy and suppressive treatment with levothyroxine is a matter of debate in patients with PC in TGCs, we conclude that this approach yields a favorable outcome in most cases, especially when the thyroid is also involved by the PC, and allows a better postoperative follow-up.

Nocturnal high-dose dexamethasone suppression test in the aetiological diagnosis of Cushing's syndrome.

Seventeen patients with well-proven Cushing's syndrome (13 with Cushing's disease, 3 with adrenal tumour and 1 presenting ectopic ACTH syndrome caused by bronchial carcinoid) were investigated by using a single-dose 8 mg dexamethasone nocturnal test. The results obtained were compared with those of the classical 8 mg Liddle's test, metyrapone stimulation, plasma ACTH concentration and with the final diagnosis reached through surgery, pathologic anatomy, and/or clinical and biochemical follow-up of the patients after treatment. The diagnostic efficacy or the predictive power of the test (defined as the ratio between the number of cases in which the diagnosis was correctly predicted and the total number of cases), was at least 82.4% vs 84.6% for the classical 8 mg Liddle's test. This percentage increased to 94.1% when the results of repeated tests on three patients with conflicting data were included. It is concluded that the nocturnal high-dose dexamethasone suppression test is a valuable tool in the aetiological diagnosis of Cushing's syndrome.