Cyclooxygenase-2 expression in medullary thyroid carcinoma.

BACKGROUND: Recent studies have demonstrated that cyclooxygenase-2 (COX-2) expression is associated with the carcinogenesis of numerous neoplasms. The aim of this study was to evaluate the role of COX-2 in medullary thyroid carcinoma (MTC). METHODS: Tissue specimens of thyroid neoplasms were obtained from 22 patients with MTC and 15 control subjects with nonmalignant thyroid specimens. RESULTS: This immunohistochemical study confirms the presence of COX-2 in a significant number of MTCs. A large area of staining was noted in only 2 patients in the control group (13%) compared with 18 (82%) in the medullary carcinoma group. On a scale of 0 to 3, the average area of positive staining measured 2.35 in the study group and 0.9 in the control group (p < .0001). The average intensity of staining on a scale of 0 to 5 (deep brown) was 2.15 and 0.8 mm, respectively (p < .001). CONCLUSION: COX-2 is expressed significantly in MTC including a larger area of staining and greater intensity than in nonmalignant thyroid tissue. These findings may have important treatment implications for the use of COX-2 inhibitors in patients with MTC.

Hyperfunctioning intrathyroid parathyroid gland: a potential cause of failure in parathyroidectomy.

BACKGROUND: The surgical success rate of parathyroidectomy is 95%. However, in rare patients, ectopic hyperfunctioning parathyroid glands may be located in the thyroid but missed on imaging studies or during surgery. The aim of the present study was to evaluate the perioperative findings in 6 patients with intrathyroid parathyroid glands treated for hyperparathyroidism in our center over a 5-year period and to review the relevant literature. METHODS: Of the 426 patients who underwent parathyroidectomy for hyperparathyroidism between 1998 and 2003 in our center, 6 (1.4%) were found to have intrathyroid glands. Their files were reviewed for clinical features, surgical approach, intraoperative findings, parathyroid gland location, and morphologic and histopathologic characteristics. RESULTS: The group included 2 men and 4 women of mean age 66 years. The diagnosis in all patients was based on an increase in serum calcium concentration (10.1-13 mg/100 mL) and parathyroid hormone level (102-320 pg/mL). The clinical symptoms were kidney stones, gastrointestinal complaints, hypertension, and osteopenia. Localization studies included ultrasonography in all patients and sestamibi in 4. When the parathyroid glands were not identified, bilateral neck and mediastinum were explored. Adenoma was diagnosed histologically in 4 patients; 2 had a double adenoma. CONCLUSION: Intrathyroid parathyroid gland is a rare condition in patients with hyperparathyroidism. In these patients, imaging may miss the pathologic gland. Despite its rarity, the possibility of an intrathyroid parathyroid should be kept in mind, and, when meticulous bilateral exploration of the neck fails to identity the hyperfunctioning gland, the surgeon should consider hemithyroidectomy.