Hassan M. Heshmati

Role of low levels of endogenous estrogen in regulation of bone resorption in late postmenopausal women

Although median levels of bone turnover are increased in postmenopausal women, it is unclear whether the low circulating levels of endogenous estrogen exert a regulatory role on these levels. This issue was evaluated by assessing the effect of a blockade of estrogen synthesis on bone turnover markers in 42 normal women (mean age ± SD, 69 ± 5 years) randomly assigned to groups receiving the potent aromatase inhibitor letrozole or placebo for 6 months. Letrozole treatment reduced serum estrone (E1) and estradiol (E2) to near undetectable levels (p < 0.0001). This treatment did not affect bone formation markers but, as compared with the placebo group, increased bone resorption markers (urine 24‐h pyridinoline [PYD] by 13.3% [p < 0.05] and 24‐h urine deoxypyridinoline [DPD] by 14.2% [p < 0.05]) and decreased serum parathyroid hormone (PTH) by 22% (p = 0.002). These data indicate that in late postmenopausal women even the low serum estrogen levels present exert a restraining effect on bone turnover and support the concept that variations in these low levels may contribute to differences in their rate of bone loss.

Thyroglossal Duct Carcinoma: Report of 12 Cases

OBJECTIVE To report the relative frequency, natural history, and optimal treatment of thyroglossal duct (TGD) carcinoma. DESIGN We retrospectively reviewed all cases of TGD carcinoma surgically treated during a 44-year period at a tertiary referral center. MATERIAL AND METHODS The computerized medical records database at Mayo Clinic Rochester was searched for patients who had the diagnosis of TGD carcinoma or TGD cyst carcinoma from 1950 through 1994. Medical records and pathologic specimens of these patients were reviewed. RESULTS Twelve patients (six male and six female patients), who were 17 to 60 years old (mean, 40), were identified. The frequency of TGD carcinoma among surgically removed TGD cysts was 0.7%. A midline upper neck mass was the initial symptom in all patients. The diagnosis of cancer was made after the Sistrunk procedure in 11 of 12 cases and preoperatively (by fine-needle aspiration biopsy) in only 1 case. All patients had papillary carcinoma. Thyroid involvement was noted in three cases. Nine patients had subtotal or near-total thyroidectomy, and three received postoperative radioactive iodine. After a mean follow-up of 13 years (range, 1 to 38), no patient had a documented local recurrence or distant metastatic involvement, and no tumor-associated mortality was observed. CONCLUSION TGD carcinoma is a rare malignant tumor that is usually diagnosed postoperatively. Papillary carcinoma is the most common pathologic finding. The recommended treatment is the Sistrunk procedure followed by near-total or total thyroidectomy by a skilled thyroid surgeon because of the possibility of intrathyroidal foci of cancer. The prognosis is excellent in patients with papillary tumor.

Advances and Controversies in the Diagnosis and Management of Medullary Thyroid Carcinoma

Recent advances in the diagnosis and treatment of medullary thyroid carcinoma (MTC) have been significant, but some issues remain controversial. MTC may occur either as a hereditary or a nonhereditary entity. Hereditary MTC can occur either alone--familial MTC (FMTC)--or as the thyroid manifestation of multiple endocrine neoplasia type 2 (MEN 2) syndromes (MEN 2A and MEN 2B). These hereditary disorders are due to germline mutations in the RET proto-oncogene. Early diagnosis and treatment considerably improve the prognosis in patients with MTC. Genetic testing can identify almost all affected individuals with hereditary disease and permits early thyroidectomy in gene carriers. Plasma CT is an excellent marker for postoperative follow-up. Imaging studies help delineate recurrent or metastatic lesions. Treatment of recurrent or metastatic disease is primarily surgical, including either palliative or microdissective surgery. Radiation therapy is reserved for skeletal metastasis or nonresectable metastatic MTC. Efficacy of current chemotherapy programs is not well established. Overall, the 10-year survival rates are approximately 65%.

Hypopituitarism Caused by Intrasellar Aneurysms

OBJECTIVE To determine the prevalence, clinical presentation, and outcome of hypopituitarism due to an intrasellar aneurysm. PATIENTS AND METHODS We performed a retrospective review of Mayo Clinic, Rochester, Minn, medical records from 1950 through 1995. We calculated the prevalence of hypopituitarism, characterized the clinical presentation, and evaluated postoperative outcomes. RESULTS Of 4087 patients with a diagnosis of hypopituitarism, 7 had hypopituitarism due to an intrasellar aneurysm, accounting for a prevalence of 0.17%. Adrenal, thyroid, and gonadal deficiencies were observed in 7, 6, and 5 patients, respectively. The prolactin level was increased in the 2 patients in whom it was measured. No patient had diabetes insipidus. All had visual impairment. In 5 patients an intrasellar aneurysm of the internal carotid artery was diagnosed preoperatively based on 1 or more imaging procedures. In the other 2 patients (1 with an internal carotid artery aneurysm and 1 with an anterior cerebral artery aneurysm), the diagnosis was made at surgical exploration. Four patients underwent a surgical procedure: 2 had direct packing of the aneurysm, and 2 had a bypass with proximal carotid occlusion or aneurysm trapping. Pituitary function remained unchanged postoperatively. CONCLUSION An intrasellar aneurysm is a rare cause of hypopituitarism (0.17% of cases). Preoperative diagnosis is essential for successful surgical outcomes. Hypopituitarism is usually permanent.

Metastases to the pituitary gland

Pituitary metastasis is a rare cause of an intrasellar mass. The authors report a series of 52 patients with intrasellar metastases diagnosed between 1950 and 1996. The patient group included 29 women and 23 men with a mean age of 60 years. Breast and lung carcinomas were the most frequent primary tumors (37% and 23%, respectively). The primary tumor was unknown in 12% of patients. In the patients with a known primary tumor, it was diagnosed after the pituitary metastasis was discovered in 20%. The mode of discovery of pituitary metastases was symptom-based (visual impairment, diabetes insipidus, hypopituitarism) in 75% of patients. Of the patients in whom prolactin was measured, 63% had hyperprolactinemia. Computed tomography and magnetic resonance imaging of the brain, available for 52% and 19% of patients, respectively, showed a pituitary mass in each case. Pituitary surgery and radiotherapy were performed in 42% and 63% of patients, respectively. Mean survival was 17 months (range, 0–240 months). Overall mortality at 1 year was 67%.

Immunocytochemical study of S-100 protein in human pituitary adenomas

SummaryThe S-100 protein was localized by immunocytochemistry in 70 pituitary tumors including 30 prolactin, 16 growth hormone, two corticotropin and 22 non-functioning adenomas. Positive immunostaining was observed in only one case (prolactin adenoma). It is concluded that in functioning and non-functioning pituitary tumors there is no particular involvement of S-100 protein-containing cells, at least under the conditions of this study.