Primary hyperparathyroidism. A surgical perspective.

Primary hyperparathyroidism is a common disorder and one that can usually (approximately 95%) be successfully treated by parathyroidectomy. PTH assays have become quite accurate for confirming the diagnosis. In patients with malignancy-associated hypercalcemia, parathyroid-like protein levels are usually increased, and radioimmunoassays being developed to quantitate serum levels of this protein will make the diagnosis easier.

The reasons for failure in parathyroid operations.

Primary hyperparathyroidism occurs in about 1 in every 700 individuals. We analyzed our experience with 81 patients with persistent or recurrent hyperparathyroidism who were treated at the University of California, San Francisco, and the Veterans Administration Medical Center, San Francisco, from January 1979 through September 1988. In the 89 reoperations performed, the following six reasons or combination of reasons were responsible for the failed initial operation: (1) in 50 patients, there were multiple abnormal glands (30 hyperplastic and 20 second adenoma); (2) in 40 patients, the tumor was located in an ectopic position (22 mediastinal, 9 deep-seated cervical, 7 intrathyroidal, and 2 undescended); (3) in 17 patients, there were supernumerary parathyroid glands; (4) in 12 patients, the abnormal parathyroid glands were found in normal locations and the tumors were missed because of surgeon inexperience; (5) in 4 patients, failure was due to metastatic parathyroid cancer; and (6) in 4 patients, failure was due to errors on frozen section examinations.

Total gastrectomy and small intestinal cholesterol synthesis in diabetic rats.

Cholesterol synthesis is increased two- to threefold in the small intestine of diabetic rats. We have observed, in three separate experiments, that the characteristic increase in small intestinal cholesterol synthesis (SICS) in diabetic rats was prevented by total gastrectomy. Food intake was increased twofold, and the small intestine hypertrophied in the gastrectomized diabetic animals.

Stimulatory effect of vasoactive intestinal polypeptide on human normal and neoplastic thyroid tissue.

Recent investigations suggest that although thyroid-stimulating hormone (TSH) is the major regulator of thyroid gland function, it is not the only hormone that regulates the thyroid gland. Another factor regulating thyroid gland function is vasoactive intestinal polypeptide (VIP), which is present in nerves that innervate thyroid blood vessels and follicles. Previous studies have documented that VIP stimulates adenylate cyclase (AC) activity in cultured normal and hyperplastic (Graves) thyroid tissue, thus increasing intracellular cyclic AMP concentration.

Deoxyribonucleic acid cytometry helps identify parathyroid carcinomas.

It may be difficult in some patients with parathyroid tumors to distinguish between parathyroid carcinoma and parathyroid adenoma on the basis of clinical and histopathological findings. Patients initially diagnosed as having a parathyroid adenoma have subsequently occasionally developed metastases, and thereby their tumor was proven to be a carcinoma. To determine whether the nuclear DNA content would correlate with the clinical course and pathology of parathyroid tumors DNA cytometry was performed on parathyroid carcinomas (9 patients), histologically atypical adenomas (10 patients), adenomas associated with severe hypercalcemia [serum calcium, greater than or equal to 13.

Mediastinal parathyroid tumors.

Mediastinal parathyroid tumors are a frequent cause of failed parathyroid operations. I therefore reviewed my experience with 285 consecutive patients treated surgically for hyperparathyroidism from January 1981 to Dec 31, 1986. Two hundred eighty-eight operations were performed on these patients (246 primary, 38 secondary, one error in diagnosis, and 53 reoperations).

Recurrent thyroid carcinoma: characteristics on MR images.

Magnetic resonance (MR) imaging was used in 32 patients, including eight with benign disease, after partial or total thyroidectomy to determine sensitivity and specificity of MR imaging in the detection of tumor recurrence, to compare signal intensities of scar versus recurrent tumor qualitatively and quantitatively, and to define the extent of recurrent tumor. Findings from surgery (n = 23), needle biopsy (n = 1), or clinical follow-up (n = 8) were used for verification. Of 24 patients with primary thyroid carcinoma, 15 had recurrence and nine had a normal postsurgical thyroid bed.

Diagnosis of recurrent hyperparathyroidism: comparison of MR imaging and other imaging techniques.

Several reports have indicated good results with MR imaging of hyperparathyroidism. However, its use in recurrent hyperparathyroidism has not been assessed separately. Thirty patients with recurrent hyperparathyroidism were evaluated by MR with both T1- and T2-weighted images.

Thyroid cancer: the case for total thyroidectomy.

Since there are no prospective studies concerning the treatment of thyroid cancer, there continues to be a considerable disagreement about the 'best' or most appropriate form of surgical treatment for patients with papillary or follicular thyroid cancer. Some surgeons recommend selective treatment depending upon the type of thyroid tumor and stage of the disease. Some advocate thyroid lobectomy and isthmusectomy, some near total thyroidectomy, and some total thyroidectomy for patients with papillary and follicular thyroid cancer.

Localization of parathyroid glands.

Parathyroid localization tests are helpful for all patients with primary hyperparathyroidism before parathyroid exploration, and they are essential for patients who have had previous parathyroid or thyroid operations. The selection of specific localization tests depends on whether the patient is undergoing an initial or a reoperative procedure, as well as on the availability of the specialized equipment and expertise of the physicians and technicians performing and interpreting these studies.

Parathyroid variants: US evaluation.

High-resolution (10-MHz) ultrasonography was performed in 181 patients with primary or secondary hyperparathyroidism during a 4-year period and evaluated retrospectively. Thirty-seven unusual-appearing parathyroid tumors were found among 235 parathyroid glands identified as abnormal. There was pathologic correlation in 36.

Carcinoids associated with multiple endocrine neoplasia syndromes.

Carcinoids occur in association with MEN types 1 and 2. To determine the relationship between carcinoids and MEN, we reviewed nine patients with carcinoids and other endocrine tumors. Analyzing these 9 patients and 56 other patients previously described in the literature, we found several clinically important relationships.

Parathyroid carcinoma versus parathyroid adenoma in patients with profound hypercalcemia.

The metabolic manifestations and operative findings in 10 patients with a diagnosis of parathyroid carcinoma were analyzed to determine whether they differ from those in patients with parathyroid adenomas and similar degrees of hypercalcemia. Two groups of patients with parathyroid adenomas were used for comparison. Group A consisted of eight patients with "atypical" benign adenomas (mean preoperative level of serum calcium: 13.

Hyperparathyroidism: comparison of MR imaging with radionuclide scanning.

Twenty-three patients with hyperparathyroidism were evaluated preoperatively with magnetic resonance (MR) imaging. Twenty patients also underwent thallium-201/technetium-99m scintigraphy. Of 22 patients with primary hyperparathyroidism, 12 had persistent or recurrent disease.

Parathyroid localization. Clinical review.

Recent advances in the techniques of preoperative parathyroid localization include ultrasonography, computed tomography, thallium-technetium subtraction scanning, magnetic resonance imaging, digital subtraction angiography with selective venous catheterization for PTH measurement, and ultrasound or CT-guided needle aspiration biopsy for cytological examination or PTH assay. These techniques are helpful for patients with hyperparathyroidism undergoing the initial operation, and essential for patients with persistent or recurrent hyperparathyroidism undergoing reoperation. Noninvasive procedures should be performed first, and the combination of any two positive studies localizes the tumor with near certainty.

Factors influencing the growth of normal and neoplastic thyroid tissue.

TSH activates the adenylate cyclase and the phosphoinositide turnover-protein kinase C-calcium systems in thyroid cells and appears to have an important but variable role in controlling the growth of both normal and neoplastic thyroid tissues. Species differences, experimental conditions, and tissue or tumor cell heterogeneity may account for this variability. Although TSH seems to be an important physiologic growth factor, it is neither the exclusive growth factor for the thyroid gland nor absolutely necessary for the effect of other thyroid growth factors.

Immunoperoxidase confirmation of parathyroid origin of ultrasound-guided fine needle aspirates of the parathyroid glands.

It may be difficult to differentiate between cells of parathyroid and thyroid origin in ultrasound-guided fine needle aspirations of the neck region, even in patients with a clinical history of hyperparathyroidism. A parathyroid hormone antibody was used in an immunohistochemical system to confirm a parathyroid origin in fine needle aspirate smears from nine patients with hyperparathyroidism. Immunoperoxidase positivity for parathyroid hormone confirmed a parathyroid origin in six of nine cases and was strongly suggestive, although equivocal, in the remaining three cases.

Parathyroid hormone: before and after parathyroidectomy.

The clinical value of measuring serum immunoreactive parathyroid hormone (iPTH) for the diagnosis of primary hyperparathyroidism is sometimes debated, and the clinical significance of an elevated postoperative serum iPTH level is unknown. Therefore we studied 141 consecutive patients with primary hyperparathyroidism before and after parathyroidectomy to determine the clinical value of measuring serum iPTH by a mid-region-specific radioimmunoassay. Eighty-eight percent of the patients with primary hyperparathyroidism had an absolute increase in the level of serum iPTH (greater than 40 microliter Eq/ml) before surgery, and the remaining patients had an inappropriately increased level of serum iPTH for the simultaneous serum calcium level.

MR imaging of the thyroid.

The thyroid gland was evaluated with MR imaging in six normal subjects and 32 patients with thyroid disease. The purpose was to evaluate signal characteristics of normal and diseased thyroid tissue; determine the contrast between normal and diseased tissue on T1- and T2-weighted images; compare relaxation times of normal thyroid, adenomas, and carcinoma; and assess the capability of MR for showing the extent of large thyroid masses. Adenomas and carcinomas were frequently isointense with normal thyroid tissue on T1-weighted images but had markedly higher intensity on T2-weighted images.

The effect of thyrotropin and cAMP on DNA synthesis and cell growth of human thyrocytes in monolayer culture.

Monolayer cultures of human thyrocytes from normal tissue (n = 10), and adenomas (n = 7), differentiated (n = 4), poorly differentiated (n = 2), and undifferentiated (n = 3) thyroid cancers were established to assess the significance of thyrotropin (TSH) and cAMP (adenosine 3',5'-cyclic monophosphate) on cell growth and DNA (deoxyribonucleic acid) synthesis. Cell growth of thyrocytes from normal and adenomatous tissues increased more rapidly (p less than 0.01) after TSH (0.

Parathyroid imaging: comparison of double-tracer (T1-201, Tc-99m) scintigraphy and high-resolution US.

Parathyroid scintigraphy using a double-tracer (T1-201, Tc-99m) subtraction technique depicted 17 of 23 (74%) parathyroid adenomas in patients with and without previous neck operations. High-resolution (10-MHz) ultrasound (US) depicted 18 (78%) of these adenomas. Average tumor size depicted by US was 17 X 10 X 8 mm (excluding a giant adenoma) and 19 X 10 X 9 mm by scintigraphy.