Parathyroidectomy: extent of resection and late results

Recurrent disease after limited parathyroidectomy for sporadic primary hyperparathyroidism

BACKGROUND

Limited parathyroidectomy guided by intraoperative parathyroid hormone (PTH) assay (QPTH) is highly successful (97% to 99%) in predicting postoperative eucalcemia, usually with less extensive dissection when compared with bilateral neck exploration. Because fewer glands are excised when resection is guided by QPTH as opposed to resection guided by gland size, a higher recurrence rate may occur. Recurrence rate after bilateral neck exploration is 0.4% to 5%, but frequency of recurrence after limited parathyroidectomy is unknown. This study reports outcomes of this operative approach in sporadic primary hyperparathyroidism.

STUDY DESIGN

Four-hundred twenty-three patients with sporadic primary hyperparathyroidism undergoing limited parathyroidectomy, followed 6 months or more or considered operative failures, were studied. In most patients, calcium and PTH levels were measured immediately after operation, and then at 2 and 6 months and yearly intervals. Operative failure is defined as hypercalcemia and high PTH within 6 months after operation, and recurrent hyperparathyroidism is hypercalcemia and elevated PTH occurring after a successful parathyroidectomy. Recurrence distributions were estimated using Kaplan-Meier analysis.

RESULTS

The success rate of limited parathyroidectomy is 97% (412/423). Four-hundred six patients were eucalcemic over an average of 34 months (median 27, range 6 to 118 months) of followup and recurrent hyperparathyroidism developed in 6 of 412 (1.5%). Estimated 5 years recurrence-free rate was 97% (95% confidence interval, 91% to 99%). Earliest and latest recurrences were diagnosed at 24 and 83 months, respectively. QPTH results did not predict any recurrence. Overall success rate was achieved, with multiple gland resections performed in only 3% of patients.

CONCLUSIONS

Recurrence rate after limited parathyroidectomy is similar to rates reported after bilateral neck exploration. Parathyroidectomy guided by QPTH is successful not only in resolving hypercalcemia in the short term, but also in providing longterm eucalcemia.

Synchronous water-clear cell double parathyroid adenomas a hitherto uncharacterized entity?

Water-clear cell hyperplasia is a rare but well-documented cause of primary hyperparathyroidism. Parathyroid adenomas of the water-clear cell type are exceptionally rare, and only 2 cases have been reported. We describe a patient with synchronous water-clear cell double parathyroid adenomas, an entity that has not previously been reported. In our case, the enlarged superior parathyroid glands were completely replaced by water-clear cells, with only a minute rim of extracapsular, histologically unremarkable parathyroid tissue. The inferior parathyroid glands were grossly unremarkable, and incisional biopsy specimens were histologically normal (no foci of water-clear cells were identified). The findings in this case are most consistent with the diagnosis of double adenomas of the water-clear cell type. We acknowledge that despite molecular proof of monoclonality of the 2 lesions, it is not possible to entirely exclude the possibility that this unusual case could be due to asymmetric hyperplasia.

Life-Threatening Hypercalcemia Associated With Primary Hyperparathyroidism During Pregnancy: Case Report And Review Of Literature

OBJECTIVE

To report a case of life-threatening hypercalcemia attributable to primary hyperparathyroidism in a pregnant patient and discuss the management of severe hypercalcemia during pregnancy.

METHODS

We describe a 28-year-old pregnant woman who had life-threatening hypercalcemia (serum calcium level of 25.8 mg/dL). Primary hyperparathyroidism was diagnosed. The patient's management and the published medical literature on primary hyperparathyroidism during pregnancy are reviewed.

RESULTS

Our patient had the highest reported serum calcium level that we could find attributable to primary hyperparathyroidism during pregnancy. After initial stabilization, parathyroidectomy was successfully performed during pregnancy. To our knowledge, this is the first report in which this profound degree of hypercalcemia did not result in an adverse maternal or fetal outcome.

CONCLUSION

Although uncommon, primary hyperparathyroidism during pregnancy may be associated with severe maternal and perinatal complications. Life-threatening hypercalcemia due to primary hyperparathyroidism during pregnancy can be successfully managed surgically during pregnancy, with good maternal and fetal outcome.

Intraoperative confirmation of parathyroid tissue during parathyroid exploration: a retrospective evaluation of the frozen section

Although the frozen section is widely used to identify tissue type during parathyroid exploration in patients with hyperparathyroidism, questions regarding its accuracy have been raised. Frozen section error has been identified as a significant factor contributing to surgical failure. The purpose of this study was to establish the accuracy of frozen section in this setting and to identify pitfalls underlying frozen section error. The final pathologic diagnoses were compared with the paired frozen section diagnoses for all patients who underwent parathyroid exploration at this institution in the period between 1984 and 1997. For those cases in which a discrepancy was identified, the original histopathology slides and the medical records were reviewed. Of the 1579 frozen sections, a definitive and accurate diagnosis could not be determined in 20 cases (1.3%); in 7 (0.4%), the frozen section diagnosis was deferred, and in the other 13 cases, the frozen section diagnosis was incorrect. Overall accuracy rate was 99.2% after deferred cases were excluded. Frozen section artifact, sampling error, and judgmental error contributed to deferred or incorrect diagnoses. Several features confounded the distinction between parathyroid and thyroid tissue in 10 cases: the coexistence of parathyroid and nodular thyroid disease; intrathyroidal parathyroid glands showing conspicuous follicle formations or abundant oncocytic cells; and thyroid nodules with fatty stroma. The frozen section is a highly reliable means of identifying tissue type during parathyroid exploration. In exceptional cases, however, the distinction between parathyroid and thyroid tissue may not be possible owing to a striking overlap seen at the clinical, gross, and microscopic levels.

Clinical and surgical aspects of double adenoma in patients with primary hyperparathyroidism

The incidence of double parathyroid adenoma in 277 prospectively documented patients suffering from primary hyperparathyroidism was 5.4 per cent (15 patients). Patients with double adenoma were all symptomatic and had a significantly higher parathyroid hormone (PTH) level and tumour weight than those with a solitary adenoma or four-gland hyperplasia. In 11 patients the adenomas were located bilaterally. Bilateral neck exploration must be performed routinely to deal successfully with this condition at initial operation. In six patients one enlarged gland was found in the thymus or posterior mediastinum. These locations should be explored, especially in patients with high PTH levels, in those in whom all four parathyroid glands cannot be detected or if only one small adenoma is found. In all such patients, selective resection of the enlarged parathyroid glands resulted in normocalcaemia (median follow-up 3.5 years). Selective resection of the pathological glands is the treatment of choice.

Surgery for parathyroid adenoma and hyperplasia: relationship of histology to outcome

Recent histopathologic evidence challenges the teaching that enlargement of a solitary parathyroid gland is invariably caused by an adenoma, whereas multiple gland enlargement results from hyperplasia. We have re-examined the parathyroid tissue obtained from 152 consecutive patients undergoing surgery for primary hyperparathyroidism and compared it with their clinical outcome. Our approach was to excise enlarged glands and biopsy the remainder. In 124 patients (82%) at least three glands were biopsied or removed. The ratio of adenoma to hyperplasia was reversed by our histologic re-examination; adenomas were found in only 27 patients (25 single, two double), whereas hyperplasia was found in 117 patients (one gland, 87 patients; two glands, 16 patients; three glands, five patients; four glands, nine patients). Normal tissue only was reported in eight patients. During a 2-year follow-up, five patients (3%) developed hypocalcemia and none developed recurrent hypercalcemia. Our results indicate that a full neck exploration with removal of all enlarged glands is more important than the histologic diagnosis in planning a successful surgical strategy for primary hyperparathyroidism.

Single and multigland disease in primary hyperparathyroidism: clinical follow-up, histopathology, and flow cytometric DNA analysis

Two-hundred seventy-four patients with primary hyperparathyroidism had selective removal of enlarged parathyroid glands. Biopsies were taken from all parathyroid glands. Normal-size glands were not resected irrespective of their histological appearance. After a mean follow-up of 13.5 years the rates of persistent and recurrent hyperparathyroidism were, respectively, 3.6% and 0.7%. Transient and permanent hypoparathyroidism occurred in 24% and 2.5% of the patients. The microscopic appearance of enlarged glands and of biopsies taken from normal-size glands were reviewed by two pathologists. Normal parathyroid glands were distinguished from abnormal glands fairly accurately (sensitivity 93%, specificity 80%). Microscopic classification of abnormal parathyroid glands as adenomas or hyperplastic glands correlated poorly with the gross classification as single or multigland disease. Flow cytometric DNA analysis of paraffin embedded parathyroid tissue showed significant differences for DNA index, % S-phase and % G2M (p less than 0.001). Differentiating single from multigland disease by means of DNA analysis was not possible. In conclusion, removal of only enlarged parathyroid glands results in acceptable rates of persistent and recurrent hyperparathyroidism. Biopsies should only be taken sparingly to prevent transient and permanent hypoparathyroidism. Microscopic examination and flow cytometric DNA analysis can differentiate normal from abnormal parathyroid glands but are unable to differentiate abnormal glands into single or multigland disease.

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.

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.

Primary hyperparathyroidism. Case report and management

A 13-year-old girl presenting with abdominal pain, polyuria, polydipsia, and radiologically confirmed renal calculi was diagnosed as having primary hyperparathyroidism. Laboratory data revealed markedly elevated serum calcium, low phosphorus, and elevated parathyroid hormone. Other parathyroid function tests also confirmed the diagnosis of primary hyperparathyroidism. Ultrasound examination showed a small echogenic nodule in the parathyroid gland. Following a single gland resection, the extremely high serum calcium level promptly decreased to normal range, and it has remained normal.

Surgical strategy in hyperparathyroidism due to solitary adenoma

Based on the postulate that parathyroid adenoma is practically always a solitary lesion, unilateral parathyroidectomy including the homolateral normal parathyroid was applied as a principle in the treatment of this form of primary hyperparathyroidism. The exploration was confined to the adenoma side if this was the first to be explored. Intraoperative oil-red-O staining of frozen sections was used to exclude the possibility of a multiglandular involvement. This principle was applied in a consecutive series of 102 patients operated for hyperparathyroidism from 1977 to 1981 and diagnosed as parathyroid adenoma. In 43 patients where the abnormal gland was found on the side explored first, unilateral parathyroidectomy was performed on that side, avoiding exploration of the contralateral side. In 45 patients where normal glands were found on the side first explored, unilateral parathyroidectomy was performed on the contralateral side. In 14 patients other types of operations were performed as the above-mentioned principle could not be achieved. At follow-up 1 to 5 years after surgery, no cases of hypocalcemia were recorded. The results of the different operations were compared as to early and late hypocalcemia. Early hypercalcemia was more pronounced after a bilateral exploration. Two of the patients who had an atypical operation had a permanent need for vitamin D in order to maintain an adequate serum calcium level. Surgical principles for various possible exploratory findings are outlined. These are based upon the idea of performing a unilateral parathyroidectomy whenever intraoperative oil-red-O staining excludes multiglandular involvement as a cause for the hyperparathyroidism.

Unilateral parathyroidectomy in hyperparathyroidism due to single adenoma

As a general principle in the treatment of primary hyperparathyroidism due to single adenoma, unilateral parathyroidectomy was applied to 50 patients and compared with another group of 50 conventionally explored patients. Twenty-five patients were explored only on the "adenoma" side. The other 25 patients were explored on both sides, avoiding biopsies at the first. In the conventionally explored patients, the adenoma was removed and one to three normal glands were biopsied. Oil-red-O technique was used in the intraoperative microscopical examination. The patients in whom the operation could be limited to the "adenoma" side had a statistically more favorable situation concerning early postoperative hypocalcemia, length of operation time, and need for calcium and vitamin D substitution. The principle of unilateral parathyroidectomy in conjunction with intraoperative oil-red-O staining technique is advocated in hyperparathyroidism due to single adenoma because it offers more reliable peroperative distinction between uni- and multi-glandular involvement, reduced operation time, decreased risk for complication, reduced early hypocalcemia, and more favorable technical conditions for reoperation.

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.