Parathyroid tumors: preoperative localization and association with other tumors

Selective venous sampling for localization of hyperfunctioning parathyroid glands

Selective venous sampling with parathyroid hormone assay was used in 46 patients with primary hyperparathyroidism. All patients had previously been operated on in the neck region. In 80 per cent of the patients the method correctly located the position of the hyperfunctioning gland(s). No complications were observed. The method was found to be of great value when evaluating patients with persistent or recurrent hyperparathyroidism.

Hypercalcemia, unusual bone lesions, and human T-cell leukemia-lymphoma virus in adult T-cell lymphoma

Extensive generalized and subperiosteal bone resorption was demonstrated in a patient with adult T-cell lymphoma and marked hypercalcemia of unclear pathogenesis. Antibody to the human T-cell leukemia-lymphoma virus (HTLV) was present in the serum of the patient, consistent with the recently reported association of adult T-cell lymphoma, hypercalcemia, and HTLV. The unique feature of this case was the presence of bone radiographic and pathologic findings consistent with hyperparathyroidism, in the absence of elevated parathormone levels. These findings contrast with the few previously reported cases of adult T-cell lymphoma with hypercalcemia, which showed lytic, sclerotic, or osteoporotic bone lesions. The authors suggest that the patient's malignant T-lymphocytes may have produced an osteoclast-activating-factor-like substance or a parathormone-like substance, which caused the striking bone changes. The exact role of HTLV in the pathogenesis of such cases remains to be determined.

Value of laboratory tests in the differential diagnosis of hypercalcemia

Eighteen laboratory tests were compared in the differentiation of primary hyperparathyroidism from hypercalcemia associated with malignancy. Statistical comparisons of the test results were carried out in four patient groups and two control groups. The patient groups evaluated were those with confirmed primary hyperparathyroidism, those with malignancy with hypercalcemia, those with malignancy without hypercalcemia, and those with surgically cured primary hyperparathyroidism. These groups allowed determination of the relative diagnostic values of the tests and a rationale for their value. After exclusion of patients with renal failure from the patient and control groups, these data indicated that the laboratory tests with the greatest differential diagnostic value, in order of efficacy, were: albumin, carboxy-terminal parathyroid hormone, venous pH, cholesterol, chloride, alkaline phosphatase, phosphorus, and the chloride/phosphate ratio. Hemoglobin, hematocrit, and red blood cell count also had some value, particularly in male patients. However, none of these tests individually achieved better than an 81 percent classification accuracy. With application of logistic discriminant analysis, only three tests--albumin, parathyroid hormone, and chloride--were identified as statistically significant in jointly improving the diagnostic separation between these two patient groups. Although the 94.4 percent classification accuracy achieved by use of these three variables in a logistic discriminant function was better than that obtained with any individual variable, incorrect classification was still a significant problem, particularly in the case of patients with malignancy and high concentrations of parathyroid hormone. With the exception of albumin and chloride measurements, the commonly available ancillary laboratory tests proposed to aid this differential diagnosis do not give any more information than the analysis of parathyroid hormone alone and merely add to the increased cost of medical care.

Static grey-scale parathyroid ultrasonography: is high-resolution real-time technique required?

Ultrasound has been used with varying success to localise parathyroid adenomas pre-operatively. We have reviewed 61 patients with pre-operative contact-scanning grey-scale parathyroid ultrasonography and subsequent surgical exploration of all four parathyroid glands. Diagnostic accuracy was 91% considering glands examined and 63% considering patients examined. There was one false positive diagnosis. False negative diagnoses (17 adenomas and five ectopic mediastinal tumours) were mainly due to upper pole adenomas, adenomas less than 10 mm X 7 mm in size and ectopic mediastinal adenomas. Static grey-scale ultrasonography is adequate for the pre-operative localisation of parathyroid adenomas, especially when high-resolution technique is not available. In fact, the overall accuracy is comparable to the recently reported diagnostic accuracy rates with high-resolution real-time systems.

Impact of sonography on surgery for primary hyperparathyroidism

The impact of preoperative sonographic localization of enlarged parathyroid glands was evaluated from the standpoint of operative time and complication rates. There was a reduction in the average time from 135 minutes when findings were false-negative to 111 minutes when findings were positive. The rate of complication was not changed by accurate preoperative localization. When the operative goal is to find all parathyroid glands in every patient, the value of preoperative localization of parathyroid tumors by any current method is slight. Should operative policy favor a search for only one enlarged and one normal gland, or should methods improve to the point that even normal parathyroid glands can be located reliably, noninvasive localization should prove to be useful, safe, and cost-effective, even when it is carried out before initial operation.

Parathyroid carcinoma: a clinical study of seven cases of functioning and two cases of nonfunctioning parathyroid cancer

Seven cases of functioning and two cases of nonfunctioning parathyroid carcinoma are presented together with a general discussion of this disease. Functioning parathyroid carcinoma may be associated with prolonged survival. The morbidity and mortality from this disease are generally related to the prolonged hypercalcemia that occurs. The hypercalcemia is best treated with excision of local recurrences; however, this surgery is most often palliative and seldom curative. The best operative results were obtained when the disease could be localized preoperatively. Neck and mediastinal exploration in the absence of physical or radiographic evidence of recurrence failed to affect serum calcium levels. Two patients with nonfunctioning parathyroid cancer did poorly compared with those with functioning parathyroid carcinoma. The few cases reported in the literature are also suggestive of a more aggressive disease. The failure of this tumor to produce parathyroid hormone may allow it to escape clinical attention until it has achieved an advanced state.

Mechanisms of hypercalcemia in malignancy

Various hormones have been implicated in the genesis of hypercalcemia in patients with malignancy. Ectopic secretion of PTH by tumor has been documented in only a few patients; rather, elevated levels of circulating iPTH have been presumed to reflect tumor production of hormone in most patients. Small fragments of PTH, as well as polypeptides larger than native PTH, have been described; their biological roles are unclear. The pattern of immunoreactivity, however, has been used to differentiate patients with ectopic hyperparathyroidism from patients with concomitant primary hyperparathyroidism. Vitamin D-like sterols produced by breast cancer seldom reach plasma levels necessary for physiological effects. Members of the prostaglandin family have been proposed to induce hypercalcemia through osteoclast activation or alteration of the immune system and also to affect the frequency of bone metastases. At present, no direct evidence is available to prove a direct role for these effects and prostaglandins are most useful as possible indicators of disease activity.

Hypocalcemia with hypoparathyroidism and renal tubular dysfunction associated with aminoglycoside therapy

Seventeen patients with malignant disease developed a complex metabolic syndrome of 2-8 weeks' duration characterized by hypocalcemia, hypomagnesemia and hypokalemia following administration of the aminoglycoside group of antibiotics. Gentamicin, Tobramycin, Amikacin, and Sisomicin were all involved. Other features noted were hypoalbuminemia, hypophosphatemia, and hypouricemia. Low immunoreactive parathyroid hormone (i-PTH) levels in the presence of hypocalcemia and absence of hyperplastic changes in the parathyroid gland examined at postmortem confirmed a diagnosis of hypoparathyroidism. Immunoreactive calcitonin levels (i-CT) were not elevated. Renal tubular wasting of potassium and magnesium was documented in six patients and excessive urinary loss of sodium, phosphate, and uric acid was noticed. Twelve patients died before recovering from the metabolic stress and five patients developed progressive renal impairment. A possible potentiating action of chemotherapeutic agents, especially Adriamycin, is suggested.

Renal cyclic adenosine monophosphate: an accurate index of parathyroid function

Measurement of total urine cyclic 3':5'-adenosine monophosphate (cyclic AMP) only incompletely discriminates between normal, hyperparathyroid, and nonparathyroid hypercalcemic patients. Only a fraction of total urine cyclic AMP is contributed by parathyroid hormone (PTH) action on the proximal nephron (renal cyclic AMP); the remainder is derived from plasma by glomerular filtration. We dtermined total urine and plasma cyclic AMP and PTH (by carboxy-terminal specific radioimmunoassay) in control, hyperparathyroid, nonparathyroid hypercalcemic, and surgically hypoparathyroid patients. Renal cyclic AMP was calculated as total urine cyclic AMP minus the filtered component. Of these determinations, only renal cyclic AMP segregated normal from hyperparathyroid, and hyperparathyroid from nonparathyroid hypercalcemic patients with complete accuracy. These data suggest that measurement of renal cyclic AMP provides an accurate index of parathyroid activity and allows clinical discrimination and appropriate treatment of the sub-groups of patients with malignancy and nonparathyroid hypercalcemia from those with hyperparathyroidism.

Advances in detection and diagnosis of head and neck tumors

Cancers of the head and neck are accessible to both inspection and palpation in the majority of patients. This accessibility allows for improvements in detection, through education of the medical profession and also of the allied health personnel. Some of the new advances in detection and diagnosis have been associated with development of new instruments. A new lens system developed by Hopkins allows a brighter endoscopic image and a significantly greater breadth of field. Needle aspiration biopsy techniques have also improved both in facility of performance and in accuracy of diagnosis. Asteriography aids in the detection of carotid body tumors. Selective parathormone studies have considerably improved the preoperative accuracy of evaluating parathyroid disease. Scans, both using ultrasound and a fluorescent iodine scan have also improved the preoperative evaluation of thyroid tumors. A challenge of detection is the realization that there is an increased risk of the development of thyroid cancer in childhood and in adults in those patients who received radiation therapy to the head and neck during infancy or childhood. A national campaign to alert potential individuals at risk should be a prime objective of the American Cancer Society.