Supernumerary Parathyroid Glands Research Articles

Preoperative sestamibi scanning and surgical findings at bilateral, unilateral, or minimal reoperation for recurrent hyperparathyroidism after subtotal parathyroidectomy in patients with multiple endocrine neoplasia type 1.

Preoperative parathyroid radioisotope scanning is of little or no value in patients with multiple endocrine neoplasia type 1 when 4 or more hypertrophied glands are present. Scanning using technetium Tc 99m sestamibi and single photon emission computed tomography will achieve a high level of sensitivity and specificity after 3 or more glands have previously been removed, justifying limited surgical reexploration. In a prospective study, the preoperative documented report of the predicted site of residual parathyroid was compared with the surgical findings in 13 patients having 19 scans and 17 reoperations. All patients belonged to one family, previously described as Tasman family 1, and were confirmed by genetic testing as having multiple endocrine neoplasia type 1. In 10 of 13 patients, reexploration was being undertaken more than 10 years after the first operation. Scanning was regarded as successful when the documented preoperative report correctly predicted the side and quadrant in which a gland was found at surgery. Surgery was regarded as successful when calcium levels decreased to or below normal levels and were maintained. All 13 scans before first reexploration were successful in identifying the location of a residual parathyroid. From a statistical viewpoint, this equates to 100% sensitivity and 92% specificity. However, despite accurate localization of 1 residual gland in every patient, 7 supernumerary glands in 4 patients and 1 parathyroid remnant in a fifth patient were not localized so that sensitivity in locating all glands in every patient was only 61%. Scans performed for persistent hypercalcemia 48 to 72 hours after reexploration in 2 patients were unsuccessful in demonstrating any residual parathyroid. Scans performed 3 months after surgery in the same 2 patients and a third patient were successful, with sensitivity and specificity of 100%. Apart from patient 11, who awaits reexploration, normocalcemia was eventually achieved in every patient, with 11 of 12 having an initial period of hypocalcemia. Three months after reexploration and trimming or resection with transplant of half a gland left at first operation, sestamibi scanning achieved sensitivity and specificity of 100% in locating supernumerary parathyroids in patients with multiple endocrine neoplasia type 1 and persistent hypercalcemia. Before first reexploration, however, scans rarely provided new information, predominantly showing only the hypertrophied half-gland remnant.

Preoperative imaging of parathyroid glands with technetium-99m-labelled sestamibi and iodine-123 subtraction scanning in secondary hyperparathyroidism

Parathyroidectomy is unsuccessful in 10-30% of uraemic patients operated on for secondary hyperparathyroidism. We investigated the usefulness of preoperative radionuclide imaging, with simultaneous recording of the distribution images of iodine-123 and technetium-99m-labelled sestamibi. 11 patients with secondary hyperparathyroidism underwent prospective imaging and parathyroidectomy. Plasma concentrations of intact parathyroid hormone (PTH) were measured in all patients before and 6 months after subtotal parathyroidectomy. Preoperative scanning showed 42 hot-spots suggesting enlarged parathyroid glands. 45 glands were discovered at surgery, and the parathyroidectomy was deemed successful in ten patients. Among the latter, one patient had a supernumerary parathyroid gland detected by scanning and resected from the left thymus. Another patient showed ectopic uptake corresponding to a large parathyroid gland in the upper mediastinum, and another had a parathyroid gland well above the thyroid. No false-positive scan findings were documented. In the patient for whom parathyroidectomy failed, preoperative scanning suggested five enlarged parathyroid glands, though the surgeon found only four glands, in their normal positions. Hyperparathyroidism persisted (intact PTH 527 ng/L, 6 months after surgery). A second scan confirmed the preoperative scan, showing a fifth parathyroid gland in the middle of the right thyroid lobe. Simultaneous recording of 99mTc-sestamibi and 123I improved the imaging of parathyroid glands in secondary hyperparathyroidism. The technique can identify ectopic and supernumerary parathyroid glands.

Surgical significance of supernumerary parathyroid glands in renal hyperparathyroidism.

In secondary hyperparathyroidism (2HPT) fundamentally all parathyroid glands, including supernumerary glands, become hyperplastic, and stimulation of parathyroid glands continues after parathyroidectomy (PTx). Therefore supernumerary glands have special significance during surgery for 2HPT, whether persistent or recurrent HPT. In the present study 570 patients underwent initial total PTx with a forearm autograft. The frequency, type, location, histopathology, and clinical significance of the supernumerary glands were evaluated. At the initial operation 90 supernumerary glands were removed from 82 to 570 patients (14.4%); 12 patients (2.1%) required extirpation of supernumerary glands for persistent/recurrent HPT. Altogether 104 supernumerary glands were identified at operation in 94 of the 570 patients (16.5%). Among these 104 glands, 25 (24.0%) were of the rudimentary, or split, type and 79 (76.0%) of the proper type. Supernumerary glands were most frequently identified in the thymic tongue (53/104, 51.0%); 32 (60.4%) of these 53 glands were identified only microscopically. In 6 of the 570 cases (1.1%), reoperation was required for persistent HPT due to supernumerary glands located in the mediastinum, and 6 patients underwent neck reexploration for recurrence. Histopathologically, 61 of 104 (58.7%) supernumerary glands, including 36 glands recognized only microscopically, showed diffuse hyperplasia, and 43 (41.3%) displayed nodular hyperplasia. Residual small supernumerary glands with diffuse hyperplasia have the potential to be transformed to nodular hyperplasia during long-term hemodialysis. Therefore all parathyroid glands including supernumerary glands should, if possible, be removed at the initial operation. Routine removal of the thymic tongue and careful examination of the regions surrounding the lower poles of the thyroid, especially on the left side, are important steps in the surgical treatment.

Surgical treatment of secondary hyperparathyroidism

Secondary hyperparathyroidism is one of the most serious complications for long-term hemodialysis patients. In our department, we performed parathyroidectomies on 215 patients between July 1973 and June 1990. We found that parathyroidectomies on 215 patients between July 1973 and June 1990. We found that parathyroidectomy was an effective treatment for advanced renal hyperparathyroidism and that after total parathyroidectomy with forearm autograft, renal hyperparathyroidism was controllable, even when hyperparathyroidism was progressive. However, the timing of this operation was important, because skeletal deformity and vessel calcification did not improve after parathyroidectomy. There were two problems after parathyroidectomy for secondary hyperparathyroidism. One was persistent hyperparathyroidism due to supernumerary parathyroid glands, particularly those located in the mediastinum, and the other was recurrent hyperparathyroidism. From our clinical and pathohistological investigations, we suspected that the proliferation of parathyroid cells changed with the progress of renal hyperparathyroidism and we found that it was difficult to prevent enlargement of parathyroid glands and recurrence of this problem.

Total parathyroidectomy with forearm autograft for secondary hyperparathyroidism in chronic renal failure.

One hundred twenty-eight patients with chronic renal failure and secondary hyperparathyroidism underwent total parathyroidectomy with forearm autograft. Postoperative clinical improvement was remarkable. In all cases, the grafted tissue functioned well, and reimplantation of the cryopreserved parathyroid tissues was unnecessary. Intact 1-84 parathyroid hormone was more sensitive than C-terminal parathyroid hormone in parathyroid hormone level (PTH) gradient assays of grafted and nongrafted forearm. The study of hypocalcemia was also helpful in obtaining more distinct PTH gradients. Five of 119 patients had supernumerary parathyroid glands (4.2%), which preoperative noninvasive image diagnosis of parathyroid glands was helpful in detecting.

An evaluation of the intraoperative staining technique using methylene blue for the detection of hyperplastic parathyroid glands

Intraoperative staining with methylene blue was employed during parathyroid surgery on 50 glands from 13 patients, 5 with primary and 8 with secondary hyperparathyroidism. Forty-seven out of the 50 glands (94 per cent) were visualized by the staining and 2 out of the 13 patients were revealed to have supernumerary parathyroid glands. Since we started using this technique, there have been no cases of persistent hypercalcemia. The results of this study support the clinical usefulness of this staining procedure for detecting hyperplastic parathyroid glands in both primary and secondary hyperparathyroidism.

Supernumerary parathyroid glands: implications for the surgical treatment of secondary hyperparathyroidism.

AbstractOf 20 patients who underwent parathyroidectomy for secondary hyperparathyroidism between 1978 and 1985, recurrent hypercalcemia occurred in 4. Three of the 4 patients had initially undergone total parathyroidectomy with autotransplantation (TP‐A) and the fourth had been subjected to removal of 3 parathyroids with autotransplantation of a portion of 1 of these glands. None of the 5 patients treated by subtotal parathyroidectomy (STP) developed recurrence. One of the 3 cases of recurrent hyperparathyroidism after TP‐A was due to graft overgrowth. Another was caused by supernumerary parathyroids subsequently removed at the time of reexploration of the neck. The third remains hypercalcemic after autograft excision and presumably still has a supernumerary gland in situ. The patient who developed recurrent hypercalcemia after removal of only 3 glands and autotransplantation remains hypercalcemic even after radical graft excision and reexploration of the neck and mediastinum.One patient treated early in the series by total parathyroidectomy without autotransplantation now has measurable levels of serum immunoreactive parathyroid hormone, presumably due to a small residual supernumerary gland. There is, thus, at least presumptive evidence of supernumerary parathyroid glands in 3 (15%) of the 20 patients in this series. The implications of this finding are discussed.

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 with hyperplasia may also have supernumerary parathyroid glands [16], especially in the inferior cervical and superior mediastinal areas that are associated with the thymus [37,38].