[Surgical treatment of primary hyperparathyroidism. A descriptive analysis]

In the last decades the primary hyperparthyroidism has become a common disease, often diagnosed by biochemical chance. The Elche General Hospital Department of Otorhinolaryngology has performed 55 parathyroidectomies between November 1996 and March 2003. Thirty-six cases (65.4%) were diagnosed as primary hyperparathyroidism. This disease usually has few symptoms. Since February 2000, Elche Hospital has available a device for quick appraisal of parathormone rate, allowing us in a few minutes to determine it and with the patient still in the operating theatre. The surgery results were: 25 solitary adenomas, 6 double adenomas and 5 hyperplasic. All patients became normocalcemic, and there were no major complications in this series.

[Surgery for secondary and tertiary hyperparathyroidism: 11 years' experience]

From 1990 to september 2001, we have performed surgery in 22 patients diagnosed as Secondary hyperparathyroidism and three patients diagnosed as Tertiary, that were sent to our clinic from the Nephrology Department. These pathologies are rare in clinical practice but they mean a lot for the patient and his family. In 17 cases we performed a subtotal parathyroidectomy, in 2 cases a total parathyroidectomy and in another 2 an adenoma was found and excised. In one of these 22 cases and following a careful exam we did not final pathological parathynoids. We present and analysed here our results with an obvious improvement in all patients but one. Finally we carry out a revision of the literature comparing our results to other similar published series.

Coexistence of primary hyperparathyroidism and thyroid disease

Primary hyperparathyroidism (HPT) and thyroid disease are both relatively common diseases, which can coexist in the same patient. However, mere coincidence does not seem to be a satisfactory explanation for this association. Some factors like prior exposure to radiation may play a role in the association. The aim of this study was to determine the frequency of thyroid disease associated with HPT in 54 consecutive patients who underwent parathyroidectomy in our center from January 1990 to December 1997. Twenty-eight (52%) patients had thyroid disease associated to HPT. The patients had a mean age of 61+/-13 yr; they were predominantly postmenopausal women. Thyroid disease was detected preoperatively in 20 (71%) patients and during the surgical procedure in 8 (29%). Two patients had previous radiation exposure; one of them with papillary carcinoma of the thyroid. Two patients had hypothyroidism. UItrasonography was performed in the majority of patients in their preoperative evaluation. A multinodular goiter was seen to be the most frequent finding (76%). In addition to parathyroidectomy, 23 (82%) patients were also thyroidectomized. In conclusion, patients with HPT showed a high prevalence of thyroid disease, especially in postmenopausal women. Unsuspected thyroid lesions were found with sufficient frequency to warrant careful preoperative and intraoperative evaluation of both glands, in order to obviate reoperation. In experienced hands, combined surgery can be safely performed. Cervical ultrasonography is useful in the preoperative detection of nodular thyroid disease in these patients.

Survival after the diagnosis of hyperparathyroidism: a population-based study

BACKGROUND

Reports of increased mortality from cardiovascular disease and malignancy in primary hyperparathyroidism have been based primarily on patients who have undergone parathyroidectomy. In order to assess the true impact of primary hyperthyroidism on mortality in the general population, we assessed survival in a large inception cohort of Rochester, Minnesota residents with primary hyperparathyroidism initially diagnosed over a 28-year span, the majority of whom were followed with uncomplicated disease.

METHODS

All Rochester residents with primary hyperparathyroidism first recognized in 1965 to 1992 were identified through the Rochester Epidemiology Project medical records linkage system. Included as cases were patients with pathologic confirmation of hyperthyroidism, hypercalcemia with inappropriately elevated parathyroid hormone levels, or hypercalcemia for more than a year with no other cause. Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death.

RESULTS

During the study period, 435 cases of primary hyperparathyroidism were identified. Altogether, parathyroid surgery was performed on 126 patients (29%), with a mean delay between the initial elevated serum calcium level and surgery of 3.3 years. Patients who underwent surgery had higher maximum serum calcium levels than the patients who were observed (mean+/-SD, 11.3+/-0.7 versus 10.7+/-0.4 mg/dL, P <0.00 1), but their mean ages were similar (54+/-16 versus 56+/-17 years). Overall survival in the patients with primary hyperthyroidism was better than expected (P=0.02), but by age-adjusted multivariate analysis, higher maximal serum calcium level was an independent predictor of mortality (RR=1.3 per mg/dL; 95% CI: 1.1-1.6; P <0.02).

CONCLUSION

Overall survival is not adversely affected among unselected patients with mild primary HPT in the community, although patients with more severe disease, as manifested by higher serum calcium levels, may have an increased risk of death.

Thyroid carcinoma found at parathyroidectomy: association with primary, secondary, and tertiary hyperparathyroidism

BACKGROUND

Frequent reports of an association between primary hyperparathyroidism (HPT) and well differentiated thyroid carcinoma, compared with the few reports of associated secondary HPT and thyroid carcinoma, may have implications for different etiologic relationships between the conditions.

METHODS

A retrospective review was performed of patients who underwent surgery for HPT between 1975 and 1996 in a single institution. The prevalence of well differentiated thyroid carcinoma diagnosed at the time of parathyroidectomy (PTX) was compared for patients with primary, secondary, or tertiary HPT.

RESULTS

There were 845 operations for HPT in 824 patients. Twenty-two patients were found to have thyroid carcinoma at the time of PTX. Thyroid carcinoma was found in 2.6% of the patients with primary and 3.2% of the patients with either secondary or tertiary HPT (P = 0.550). Twenty-one of the patients had papillary carcinoma and 1 had a follicular carcinoma. Eighteen of the carcinomas were < 1 cm in size. A prior history of head and neck irradiation was associated with the diagnosis of thyroid carcinoma at the time of PTX (P < 0.001). Neither renal failure, organ transplantation, female gender, lymphocytic infiltration, nor follicular adenoma of the adjacent thyroid were significant in the association between HPT and thyroid carcinoma.

CONCLUSIONS

These data suggest that the association between thyroid carcinoma and HPT is coincidental and possibly related to the closer surveillance of the thyroid gland due to PTX and often concomitant removal of thyroid tissue. Patients with HPT and a history of head and neck irradiation are at increased risk of thyroid carcinoma.

Association of hyperparathyroidism with nonmedullary thyroid carcinoma: review of 31 cases

In a series of 948 patients operated on for primary hyperparathyroidism (HPT) by one surgeon (JNA) from 1952 to 1992, there were 242 (26%) instances of coincidental thyroid and parathyroid disease. Of these, 211 had benign thyroid lesions. In the remaining 31 cases HPT was associated with nonmedullary thyroid carcinoma; all were treated by resection of parathyroid adenomas and thyroidectomy. One patient died of unrelated cause (carcinoma of breast) 11 years following surgery. The remaining 30 patients are living and well 2 to 20 (mean 8.2 years) years after surgery; there was no recurrence or thyroid cancer-related mortality in the series. In contrast to prior reports, only six (20%) of our patients had a history of prior radiotherapy. We suggest that during neck exploration for HPT, the entire thyroid gland be evaluated and all palpable nodules resected and submitted to pathologic study.

Primary hyperparathyroidism in younger and older patients: symptoms and outcome of surgery

Two-hundred and fifty patients undergoing initial exploration for primary hyperparathyroidism were analyzed for differences in clinical presentation, biochemical status, pathology, and outcome of surgery. In patients less than 60 years of age (younger patients, n = 119) the most common preoperative symptoms and signs were fatigue (40.3%), bone pain (33.6%), renal stones (31.0%), hypertension (27.7%), and psychiatric illness (27.7%). In patients greater than or equal to 60 years of age (older patients, n = 131) the most frequent symptoms and signs were hypertension (46.6%), fatigue (35.1%), bone pain (30.5%), muscle weakness (28.2%), and joint pain (22.9%). Renal stones were 2.6 times more common (p less than 0.001, chi 2) in younger patients and hypertension 1.7 times more common (p less than 0.05, chi 2) in older patients. There was no significant difference in the preoperative and postoperative laboratory values typically associated with primary hyperparathyroidism. Double adenomas were more common in older (9.2%) than in younger patients (2.5%, p less than 0.05, chi 2). Surgical cure was obtained in 98.8% of patients, and after parathyroidectomy 83% of the younger and 82% of the older patients experienced substantial relief of pre-operative symptoms. Specific questioning revealed most patients to be symptomatic and older patients appear to receive the same clinical and metabolic benefits from parathyroidectomy as younger patients.

Unilateral neck exploration for primary hyperparathyroidism: analysis of a controversy using a mathematical model

Most endocrine surgeons explore both sides of the neck and identify all parathyroid glands when operating on patients with primary hyperparathyroidism. Others, however, advocate the unilateral approach, i.e., if an adenoma and a normal gland are identified, the contralateral side is not explored. We analyzed the strategy of the unilateral approach using a mathematical model to determine the variables that influence the probability of missing a tumor on the unexplored side of the neck. Assuming the frequency of single adenoma is 80%, hyperplasia 14%, double adenomas 4%, triple adenomas 1%, and carcinoma 1%, and the probability of missing a tumor on the explored side is 5%, we found that: 1. Only 41% of the patients treated by the unilateral approach undergo unilateral exploration. This is increased to 62% when a localization study with a sensitivity of 80% is used pre-operatively. 2. The probability of missing a tumor on the unexplored side of the neck parallels the prevalence of multiple adenomas. Half of the patients with triple adenomas and two-thirds of the patients with double adenomas will have a missed tumor when treated by the unilateral approach. 3. Patients who undergo unilateral exploration have an additional 7% to 8% probability of missing a tumor that would have been found if bilateral exploration is performed. This risk is lowered to 2% by a pre-operative localization study that is 80% sensitive. 4. A prospective study will require 684 patients, randomized to the unilateral or bilateral approach, to have an 80% statistical power (alpha = 0.05, beta = 0.20) of detecting a difference between a 5% and a 10% risk of missing a tumor.

Management of hyperparathyroid patients with grave hypercalcemia

During recent years the total number of patients undergoing surgery for hyperparathyroidism has markedly increased, but the annual number of cases with substantial hypercalcemia has remained unchanged. Parathyroid carcinoma and water clear cell hyperplasia cause more severe hypercalcemia than other kinds of hyperparathyroidism. Grave hypercalcemia due to hyperparathyroidism is more common among the elderly, but can occur during pregnancy and also among children. Occasionally, a patient with hyperparathyroidism can also have another cause of the hypercalcemia and does not become normocalcemic until adequately treated for both. The suspicion of grave hypercalcemia should arise due to its clinical features. Determination of serum calcium and intact parathyroid hormone concentrations establishes the diagnosis. The basic treatment of grave hypercalcemia is to rehydrate the patient and to restore the sodium losses. To further lower the serum calcium value we have found bisphosphonates to be very effective. The definitive treatment of grave hypercalcemia due to hyperparathyroidism is surgery. As a last resort, frail patients with grave hyperparathyroidism can undergo surgery under local anesthesia. Repeat operations can improve the prognosis of patients with metastatic parathyroid carcinoma. Selective venous catheterization with blood sampling for determination of intact parathyroid hormone can be helpful in localizing recurrent disease.

Surgical therapy of patients with primary hyperparathyroidism: long-term benefits

Primary hyperparathyroidism was thought 30 years ago to be a rare disease, and the diagnosis was most often made in patients presenting with either bone disease or kidney stones. Today the minority of patients with hyperparathyroidism present with such symptoms, a fact accounted for by the introduction into general medical practice three decades ago of laboratory technology for efficiently determining the serum concentrations of various blood minerals, including calcium. Hypercalcemia was detected more frequently, and it was realized that most patients with hyperparathyroidism either had minor symptoms, such as constipation, polyuria, tiredness, and muscle weakness, or they were "asymptomatic" and indistinguishable from normal subjects. It was thought that primary hyperparathyroidism was a progressive disease and that sooner or later all patients would become symptomatic and require parathyroidectomy. Since this operation was curative in a high percentage of cases, it was recommended for virtually all patients once the diagnosis was established. In this contribution the long-term benefits of parathyroidectomy in patients with and without symptoms from primary hyperparathyroidism are reviewed. It is concluded that a multicenter prospective randomized trial is needed to resolve the indications for operative and nonoperative management of patients with this disease.

Natural history of treated primary hyperparathyroidism

A follow-up study of patients operated on for primary hyperparathyroidism revealed that recurrent hypercalcemia is uncommon in patients with solitary adenoma, but common in patients with multiglandular disease. The result of parathyroidectomy on the different symptoms of primary hyperparathyroidism is good. On the other hand, even after successful surgery, patients with primary hyperparathyroidism have poorer health than controls, and they also have a higher mortality rate. Most of the deaths in the primary hyperparathyroidism group are caused by cardiovascular disease. The effect of the preoperative serum calcium level on the later state of health is evident.

Hyperparathyroidism subsequent to neck irradiation. Risk factors

A follow-up examination of 444 persons treated with x-rays for tuberculous cervical adenitis was performed to determine if the risk for hyperparathyroidism (HPT) following radiation exposure can be related to the age at treatment, the dose of x-rays, or the sex of the patient. The overall incidence of HPT was 14%. There was no definite age-dependent difference in susceptibility to the induction of HPT. The doses of radiation among the 63 subjects who developed HPT ranged from 0.6 to 45.7 Gy (60-4570 rad). There was a statistically significant positive correlation between the dose of radiation and the probability of developing HPT. After doses of 14 Gy (1400 rad) or more 29% of the subjects had developed HPT. After neck irradiation women had twice the relative risk of men of developing HPT. This sex ratio was lower than in the series of nonirradiated HPT patients treated at the same institution during the time of the follow-up study.

Acute hyperparathyroidism successfully treated by total parathyroidectomy and parathyroid autotransplantation

Acute hyperparathyroidism occurs infrequently and sometimes represents a diagnostic problem in urological patients. We report a case of acute hyperparathyroidism successfully treated by total parathyroidectomy and parathyroid autotransplantation.

Lessons of parathyroid reoperations

The case histories of the 23 patients in this series demonstrate the importance of a systematic approach to parathyroid surgery. Ligation of the superior thyroid vessels and mobilization of the upper pole of the thyroid are often necessary to find the superior parathyroid glands that are located on the posterior surface of the thyroid. Devascularization of the thyroid gland does not occur with this maneuver because of abundant collateral circulation from the inferior thyroid artery and tracheal vessels. Normal appearing parathyroid glands should not be resected because this procedure does not treat hypercalcemia and may leave the patient with insufficient parathyroid tissue if an adenoma is found at a later date. Bilateral cervical exploration [35,36] is performed before resection of any abnormal appearing parathyroid tissue. Patients may also have supernumerary parathyroid glands [16], especially in the inferior cervical and superior mediastinal areas that are associated with the thymus [37,38].

Reoperative surgery for hyperparathyroidism

The difficulties created by an unsuccessful initial operation can usually be avoided by choosing experienced surgeons, identifying four glands, and selectively excising grossly abnormal parathyroid tissue. Patients with multiple endocrine adenomatosis or familial hyperparathyroidism should have a subtotal parathyroidectomy. Reoperative surgery is difficult and although it is successful in approximately 70 to 80 percent of patients, it is associated with a significant morbidity which includes persistent hypercalcemia, hypoparathyroidism, and nerve injury. Reoperative parathyroid surgery should be done in specialized centers where the sophisticated methods of preoperative localization and surgeons experienced in this field are available.

[Reoperations for persistent and recurrent hyperparathyroidism (author's transl)]

The results of 26 reexplorations in 24 patients with primary hyperparathyroidism are reported. In 20 patients the disease was classified as persistent, in 3 as recurrent. The diagnosis was confirmed by measurement of calcium and phosphate in serum and urine and by serum-PTH. All patients were symptomatic. Localisation of the tumors was possible by following the embryology and topographical anatomy of the parathyroids during surgery; localization was not as successful in the various preoperative investigations used. Postoperatively, no patient was hypercalcemic. The success rate was 100% for 21 patients, with a follow-up time of more than 6 months. Use of cryopreservation and autotransplantation of the endocrine tissue proved very advantageous; this technique was performed successfully in two of ten hypocalcemic patients and still may be considered in another three patients.

Reoperation for primary hyperparathyroidism

The reasons for failure of the initial exploration and the results of reoperation were analyzed in 53 patients with a diagnosis of primary hyperparathyroidism, 29 of whom were referred after initial operations elsewhere. Seventy-nine reoperations were performed. Sternotomy was used in 15 patients, and in retrospect was necessary in only 5. There was no operative mortality. The reasons for initial failure were incorrect diagnosis in 6 patients, true recurrence in 4 and persistent disease in 43. Persistence was caused by surgical failure in two thirds and pathology failure in one third. Of 47 patients reoperated on for hyperparathyroidism, 39 (83 percent) were cured, a rate warranting this type of surgery. Analysis of a long-term series of initial operations demonstrates a persistence rate of 5 percent (24 of 461) and a recurrence rate of 1 percent (4 of 461) in this disease. The need for reoperation was les than 1 percent over the recent 5 year period.

Vascular effects of parathyroid hormone (PTH)

PTH causes dose dependent transient vasodilatation in various vascular beds, specifically renal, coeliac, coronary, but not osseous. It has an acute dose-dependent hypotensive effect in the intact animal which is not mediated by alpha- or beta-adrenergic, cholinergic or histaminergic mechanisms. Aortic medial smooth muscle cells respond to PTH with an increase of cAMP, cGMP and, presumably via protein kinase, with activation of phosphorylase B kinase. The acute vasodilatory effect of PTH is antagonised by indomethacin and diclofenac as well as by ouabain, suggesting that the membrane Na-K pump and prostaglandins are involved in PTH-induced vasodilatation. Parathyroidectomy and a high calcium diet attenuate the rise of arterial pressure in experimental hypertension, pointing to some permissive effect of PTH for development hypertension. This is most likely due to long term effects of PTH on vessel wall calcium content and exchange. This chronic effect of PTH may explain the high prevalence of hypertension in patients with primary hyperparathyroidism.

Acute hyperparathyroidism. Clinical, laboratory and ultrastructural findings in a variant of primary hyperparathyroidism

In a series of 6 patients out of 47 cases with extrarenal hyperparathyroidism we investigated the clinical, laboratory and ultrastructural peculiarities of acute hyperparathyroidism. It was found that there are characteristic differences between both entities which, however, are fluid. Clinically more severe were neuromuscular psychiatric and mental signs. In the laboratory parameters PTH determined by radioimmunoassay and calcium were higher whereas hemoglobin was lower. The weights of the adenomas did not differ in both groups and this was also true for light microscopy findings. Electron microscopy revealed accelerated hormone extrusion and autodigestion of retrived membrane material in the cases of acute hyperparathyroidism similar to characteristics of parathyroid cells stimulated by hypocalcemia in tissue culture.

Twenty-five year experience with primary hyperparathyroidism at Columbia Presbyterian Medical Center

A retrospective review of 500 patients with primary hyperparathyroidism seen from 1951 to 1975 was conducted; the effect of routine screening of calcium and phosphate levels (initiated in 1968) on the incidence and spectrum of the disease was analyzed. The majority of the patients (77%) were diagnosed in the eight-year period after routine biochemical screening was instituted. Comparing the group of patients diagnosed before the advent of biochemical screening and those diagnosed since screening was instituted, we found: (1) a small but significant increase in the number of asymptomatic patients diagnosed (from 2% to 12%); (2) no change in the incidence of related medical disorders, i.e., nephrocalcinosis and hypertension; (3) no change in the incidence of primary hyperplasia and adenoma; and (4) no change in the mean serum calcium level, the mean age at diagnosis, or the number or location of the involved parathyroid glands. Although routine calcium screening has identified significantly more cases of primary hyperparathyroidism, screening apparently does not enable diagnosis at an earlier stage.

Hyperparathyroidism in persons treated with X-rays for tuberculous cervical adenitis

Follow-up examinations of one hundred persons treated with x-rays for tuberculous adenitis between 1930 and 1946 have been carried out to determine if there is an increased incidence of hyperparathyroidism (HPT) after radiation exposure. Neck explorations were done in patients with hypercalcemia and signs and symptoms compatible with HPT. Individuals with thyroid masses were also operated upon when examination of fine needle specimens gave suspicions of malignancy. Eleven subjects were found to have developed parathyroid adenoma or hyperplasia. Four other individuals have hypercalcaemia but are asymptomatic. The mean absorbed dose in the parthyroid glands varied between 75 and 2,200 rads. Six individuals received more than 1,200 rads; four of them later developed HPT, while no HPT occurred below a dose of 300 rads. The high incidence of HPT among patients who had been heavily exposed to radiation suggests a cause and effect relationship between radiation treatment and development of HPT.

Family studies in patients with primary parathyroid hyperplasia

The relatives of 25 index patients with primary parathyroid hyperplasia were tested for hypercalcemia. At least 13 of these patients had one or more first degree relatives with hypercalcemia. Two familial syndromes each with autosomal dominant transmission were recognized. Two index patients were part of large kindreds categorized as having familial hypocalciuric hypercalcemia (FHH). Manifestations of multiple endocrine neoplasia type I were present in the kindreds of at least four other index patients (FMEN I). In seven other kindreds there were too few affected members to allow definitive classification. Differences between manifestations of FHH and FMEN I were described. Among offspring of affected persons in kindreds with FHH, as distinct from FMEN I, the prevalence of hypercalcemia approached the theoretic maximum of 50 per cent during the first two decades. In FHH, nephrolithiasis and peptic disease were unusual; moderate hypercalcemia occurred without hypercalciuria; and subtotal parathyroidectomy did not abolish hypercalcemia. Concentrations of peptide hormones other than parathyroid hormone (PTH) were normal in those with FHH; in FMEN I high concentrations of glucagon in plasma were found in five of six patients tested, and high concentrations of gastrin were found in three of 12 patients. Hypergastrinemia generally accompanied obvious peptic disease. Distinction of the two conditions is important since patients with FHH may not benefit from subtotal parathyroidectomy, but they generally have a better clinical prognosis than do patients with FMEN I.

Blood pressure in subjects with hypercalcaemia and primary hyperparathyroidism detected in a health screening programme

Primary hyperparathyroidism was the most likely diagnosis in sixty-eight non-thiazide treated patients with hypercalcaemia detected in a health screening. The group included fifty-five females and thirteen males with a mean +/- SEM age of 55.0 +/- 0.7 years. On a pair basis, these patients were compared with a series of sixty-eight age- and sex-matched normocalcaemic subjects selected from the health screening register. Five subjects in each group were receiving medication for hypertension. Systolic and diastolic blood pressures were significantly higher in the hypercalcaemic subjects in the remaining fifty-eight pairs (P less than 0.001). This difference was unrelated to impaired renal filtration and many other factors associated with hypertension. It is concluded that hypercalcaemia and/or other effects of deranged parathyroid function per se may result in a blood pressure elevation on which need not necessarily attain the level of hypertension.

Parathyroidectomy: extent of resection and late results

Opinion is divided as to the necessary extent of parathyroid resection in primary hyperparathyroidism. Some surgeons urge that subtotal parathyroidectomy be performed routinely, while others reserve subtotal resections for patients with parathyroid hyperplasia. In a review of 102 patients treated by parathyroidectomy for primary hyperparathyroidism and subsequently followed up for an average of 6 years, there were 73 patients with parathyroid adenoma, 26 with hyperplasia and 3 with carcinoma. The adenoma was not found at the first operation in only 3 cases; in the other 70 after removal of the adenoma no further hypercalcaemia was observed during the follow-up period. Persistent or recurrent hypercalcaemia was a problem in 9 out of the 26 patients with primary hyperplasia who had inadequate resection at the first operation, and also in the 3 patients with carcinoma. Experience shows that peroperative biopsy with frozen section of all the parathyroids is useful in confirming their identity and can be a guide to the type of disease present and the appropriate extent of resection.

Parathyroid hyperplasia in primary hyperparathyroidism: a review of 85 cases

Parathyroid hyperplasia of all four glands was found to be the cause of primary hyperparathyroidism in 85 of 557 cases seen at the Massachusetts General Hospital between 1930 and 1973. There were 66 cases of chief cell hyperplasia and 19 cases of clear cell hyperplasia that were grossly, microscopically, and ultrastructurally distinct. Although the clinical findings overlap, there are several differences in the signs and symptoms between these two forms of hyperplasia. Both types are treated by subtotal removal of all the parathyroid tissue. Removal of insufficient tissue has left residual hyperparathyroidism in 45% of those with chief cell hyperplasia and 11% of those with clear cell hyperplasia after what was thought to be definitive surgery. Postoperative hypoparathyroidism was found in 15% of the patients with chief cell hyperplasia and in none with clear cell hyperplasia. These findings further suggest that removal of three and one-half glands in the more than 86% of patients with one gland involvement (adenoma or carcinoma) as the cause of primary hyperparathyroidism is unwarranted.

Studies on the non-adenomatous glands in patients with a solitary parathyroid adenoma

The properties of the non-adenomatous glands in 22 cases of primary hyperparathyroidism due to solitary adenoma were studied. The mean glandular and parenchymal cell weight was somewhat lower than that found by others in glands from euparathyroid subjects. In almost all glands the dark chief cells predominated. This cell type indicates endocrine activity. With some exceptions the glandular endocrine activity seems to be less pronounced than in the concomitantly resected adenoma. Histologically there was no apparent signs of atrophy or hyperplasia in the nonadenomatous glands. The clinical relevance of the findings is discussed.