Heterogeneous gland size in sporadic multiple gland parathyroid hyperplasia

BACKGROUND: The success rate for bilateral exploration in patients with primary hyperparathyroidism approaches 95%. Multiglandular parathyroid hyperplasia accounts for approximately 10% to 30% of primary hyperparathyroidism. The incidence of recurrent or persistent hyperparathyroidism is highest in familial forms of the disease, in which multiglandular disease is more common; this may be due to asymmetric enlargement of parathyroid glands. Because of improvements in tumor-imaging capability, some surgeons are now advocating unilateral exploration for primary hyperparathyroidism, but there is limited experience concerning how often these imaging methods fail. STUDY DESIGN: The outcomes of 7 patients who had sporadic primary hyperparathyroidism with multigland hyperplasia were reviewed. We gathered demographic data and laboratory values and reviewed radiologic tests, surgical findings, pathologic findings, and postoperative followup. RESULTS: All patients underwent preoperative localization with ultrasonography and technetium/sestamibi scans. The sensitivity of these two tests for the dominantly enlarged gland was 100% for both, but dropped to 0% and 5%, respectively, for all other enlarged glands. The sensitivity of CT and MRI for the dominant tumor was 67% (2 of 3) and 50% (1 of 2), respectively. Six of 7 patients underwent subtotal (3(1/2) gland) parathyroidectomy. The mean volume of all glands was 1.51+/-5.89 cm3 compared with a mean of 5.66+/-11.4 cm3 for all dominant glands and 0.123+/-0.1 cm3 for all nondominant hyperplastic glands. There was a large amount of variability between the volumes of dominant and other glands as demonstrated by large SDs from the mean. CONCLUSIONS: There is a marked heterogeneity in gland size in patients with sporadic multigland hyperplasia, which is similar to that found in multiple endocrine neoplasia type I. This heterogeneity may result in failure to recognize multigland disease if a unilateral neck exploration is performed. Intraoperative parathyroid hormone assay may prove to be an important adjunct in this population of patients who have unsuspected multigland disease.     

Technetium-thallium scintiscanning for localization of parathyroid adenomas and hyperplasia. A reappraisal

The dual tracer nuclear scintiscan using technetium and thallium to localize enlarged or ectopic parathyroid tissue has been reported to be highly accurate and efficacious. Fourteen previous series reporting results of the technique have been compiled from the literature and analyzed. This analysis has revealed a total of 317 surgically confirmed scan results with a low false-positive rate (17 of 317 scans), a sensitivity rate of 82 percent, and an overall accuracy rate of 78 percent. Forty-five patients from five Portland area hospitals have been retrospectively studied. They had a total of 49 preoperative scans. In our experience with the scan, a higher false-positive rate (4 of 45 scans), a sensitivity rate of 78 percent, and an overall accuracy rate of 73 percent were noted. The scan's effectiveness in acknowledged areas of difficulty in parathyroid surgery, such as patients with ectopic adenomas, hyperplastic glands, and those with previous neck explorations, has been analyzed. We conclude that the scan is a useful preoperative localization tool, especially in patients with ectopic adenomas or with persistent hypercalcemia after neck exploration. However, it is less accurate than initially reported in complex patients, and additional localization techniques are frequently required.     

The anatomy of parathyroid hyperplasia

Parathyroid hyperplasia aids the surgeon in studying parathyroid anatomy for several reasons: (a) Nature magnifies the glands in hyperplasia; (b) there is a strong clinical imperative to find all glands; (c) histologic controls help guide the dissections; and (d) postoperative clinical and laboratory responses help determine the presence of supernumerary glands. In this study of parathyroid hyperplasia we found four glands in each of 34 patients (136 glands total--37 operations). Six patients (18%) had parathyroid glands totally covered by thyroid tissue, five patients (15%) had mediastinal glands, one patient (3%) had a retroesophageal gland, and one (3%) had a "kissing pair." In addition, after four-gland parathyroidectomy, three patients gave evidence of functioning supernumerary glands (9%). Abnormalities in parathyroid anatomy occurred in almost half (47%) of these patients with parathyroid hyperplasia.     

Intrathyroid parathyroid adenomas

The authors present 27 cases of intrathyroid adenomas of the parathyroid glands that made up 22.68% of 119 patients operated on for parathyroid tumors. Clinical manifestations of primary hyperparathyrosis were diagnosed in 10 out of 27 patients. In 17 of these patients the hormonal-inactive parathyroid adenomas, detected accidentally during operations for different diseased of the thyroid gland, were ablated. The authors stress a careful revision of the thyroid to be necessary in order to exclude an intrathyroid localization of parathyroid neoplasms which can result in persistence of the disease if not ablated.     

Autogenous parathyroid grafts for generalized primary parathyroid hyperplasia: contrasting outcome in sporadic hyperplasia versus multiple endocrine neoplasia type I

Sixteen patients with generalized primary parathyroid hyperplasia were treated with attempted total parathyroidectomy and placement of an autogenous parathyroid graft in the forearm musculature; these patients have been followed for up to 79 months. We assessed completeness of parathyroidectomy on the basis of the background immunoreactive parathyroid hormone (iPTH) value 3 to 7 days after surgery, which predicted the chance of a graft-independent recurrence or persistence of hyperparathyroidism (0/8 if undetectable versus 4/5 if normal or high). Total parathyroidectomy was sometimes difficult to achieve because of the presence of supernumerary or ectopic parathyroid glands; to enhance the success rate of total parathyroidectomy, we suggest both the use of preoperative ultrasonography to locate intrathyroidal parathyroids and a routine search for supernumerary parathyroids that includes transcervical thymectomy. Graft function was monitored by measuring the secretory gradient for iPTH (the difference between the two antecubital fossae). Gradients on postoperative days 3 to 7 were barely detectable, but by 3 weeks, larger iPTH gradients were noted in every case. By 4 months, the graft could maintain normal serum calcium levels in all but one case. Autonomous graft function has evolved in four of six evaluable patients with type I multiple endocrine neoplasia (MEN I), but in none of the nine patients with sporadic hyperplasia (p = 0.043). A prospective study is needed to determine whether the use of a smaller number of parathyroid fragments for the autogenous graft in known MEN I patients might delay recurrence.     

Preoperative localization of parathyroid adenomas

During a 12-month period, 64 patients were operated on for primary hyperparathyroidism. Sixty-one had single adenomas and 3 had double adenomas. Preoperative imaging was used to localize the adenomas. Half of the patients (32 of 64) had magnetic resonance, thallium-201/technetium-99m subtraction scintigraphy, and high-resolution ultrasonography; the other 32 patients had 1 or 2 of the imaging modalities. Sensitivity and specificity of magnetic resonance imaging was 82 percent and 97 percent, respectively; the sensitivity and specificity of the other two modalities was 59 and 98 percent for subtraction scintigraphy and 73 and 98 percent for ultrasonography. The use of preoperative imaging facilitated surgical exploration, reduced operating time, and resulted in an increased number of successful operations. There were no negative explorations in this series as compared with 19 negative explorations (2.6 percent) in our prior experience with 720 operations.     

The blood supply of mediastinal parathyroid adenomas.

Arteriography for parathyroid localization following unsuccessful neck surgery should include selective catheterization of the inferior thyroid and internal mammary arteries bilaterally. When the arterial supply to a mediastinal adenoma arises from the internal mammary artery, recovery from the neck may not be possible and an open mediastinal exploration (or embolization) should be considered.     

Localization of parathyroid adenomas by computer-assisted parathyroid scanning.

In an attempt to localize adenomas of the parathyroid glands 36 patients with suspected hyperparathyroidism were studied with a computer-assisted double isotope scanning technique. Six patients were excluded from the statistical analysis because of uninterpretable scans. A definite localization was made with the computer-assisted scan in 16 patients. In 14 of these patients the site of the tumours was correctly predicted. In 14 patients no localization was seen on the scan. Four of these patients were classified as false negatives. In 14 out of the 16 correctly localized tumours two-thirds had weights equal to or less than 1-5 g.     

散发性甲状旁腺腺瘤基因改变的研究进展

散发性甲状旁腺腺瘤是引起原发性甲状旁腺功能亢进的重要原因.但甲状旁腺腺瘤发病机制不清且缺乏早期特异性诊断指标.近年来随着分子生物学的发展,甲状旁腺腺瘤在基因水平的研究取得了很大的进展.本文就其在分子生物学的改变做一综述.     

Ultrasonography in the localization of parathyroid adenomas

The use of ultrasonography in the diagnosis of a parathyroid adenoma is described, and the limitations and advantages of this method are discussed.     

A role for enhanced integrin and FAK expression in uremia-induced parathyroid hyperplasia

Parathyroid (PT) hyperplasia is a major feature of secondary hyperparathyroidism (SH) in uremia. The transforming growth factor-alpha (TGFalpha) / epidermal growth factor receptor (EGFR)Ethgrowth loop is the main contributor to uremia-induced PT hyperplasia. Since integrin beta1 and focal adhesion kinase (FAK) are known to directly activate cell growth and enhance EGFR-driven growth, these studies examined their contribution to PT hyperplasia in uremia. Western blot analysis was used to measure the expression of EGFR, integrin beta1, and the non-receptor integrin-sensitive FAK, in PT glands from 8 hemodialysis patients with various degrees of SH at the time of the surgery, and in a normal human PT gland. In all patients, PT EGFR expression was higher than in the normal control. Integrin beta1, a direct activator of EGFR-driven growth, was increased in 5 of the 8 hyperplastic glands, whereas 7 out of 8 PT glands showed a marked enhancement in FAK expression, an elevation unrelated to increases in integrin beta1, but directly associated to time in hemodialysis. Similar increases in PT FAK content were observed after 1 month after the onset of uremia by 5/6 nephrectomy in rats. These findings suggest that in kidney disease, the increased PT cell growth driven by enhanced EGFR could be further aggravated through elevations in integrin beta1 and FAK expression.     

Therapy of suspected intrathoracic parathyroid adenomas

BACKGROUND AND AIMS: Ectopic mediastinal parathyroid adenoma as a cause of primary hyperparathyroidism (pHPT) can normally be resected from conventional collar incision. In rare cases with adenomas deeper in the chest, a transthoracic approach is necessary. PATIENTS/METHODS: We report our experience of 19 patients with suspected mediastinal parathyroid adenomas from a total of 1035 patients with pHPT who were operated on between 1986 and 2000 using an open approach (sternotomy or thoracotomy) or video-assisted mediastinal or thoracoscopic surgery (VAMS/VATS). RESULTS: Fourteen patients underwent an open approach with a success rate of 71% (10 of 14). Four patients remained hypercalcaemic. There were four complications in three patients: three permanent recurrent nerve palsies and one chylus fistula, requiring further surgery. VATS was successful in three of four patients with conversion to sternal splitting because of a false-negative frozen section in one patient. Another patient had parathyroid adenoma retrosternally which could not be resected by means of VAMS and had to be excised using a transsternal approach. There were no complications of minimal invasive procedures. All five patients were normocalcaemic after the operation. CONCLUSION: Ectopic parathyroid adenomas not resectable by means of a collar incision are rare causes of pHPT and comprise 1.25% of all patients with pHPT in our series. For these patients, VATS revealed an alternative to conventional open procedures. In questionable cases, however, the collar incision should precede the VATS procedure.     

Diagnosis and treatment of parathyroid adenomas

The classical manifestations of primary hyperparathyroidism (hypercalcemia, hypophosphatemia, hypercalciuria, increased blood alkaline phosphatase level, and bone changes of the type of generalized osteoporosis) were found in approximately half of patients in a group of 23 who were examined. When Recklinghausen's disease is suspected, the patients must be subjected to a purposeful examination. The intraoperative diagnosis of parathyroid adenoma is difficult. In distinction from thyroid tissue, a lymph node, and adipose tissue a parathyroid adenoma almost always has a vascular pedicle, which makes verification of the diagnosis easier.     

Radioguided tumorectomy in the management of parathyroid adenomas

HYPOTHESIS: A clearly localizing sestamibi scan predicts a successful minimally invasive radioguided parathyroidectomy that can be performed with a shorter operative time, low morbidity, and decreased duration of hospital stay. DESIGN: Review of prospectively gathered data and patient medical records. SETTING: Hospitalized care.Patients and METHODS: Parathyroidectomy was performed on 55 patients with a secure biochemical diagnosis of hyperparathyroidism and a sestamibi scan performed at the University of Connecticut Health Center. Of the 40 patients with a clearly positive sestamibi scan result, 31 underwent radioguided parathyroidectomy. The results of radioguided parathyroidectomy are compared with those of the standard bilateral exploration performed in the remaining 24 patients. MAIN OUTCOME MEASURES: Ionized calcium concentration, postoperative complications, and operative time. RESULTS: All patients were cured of hyperparathyroidism, and no patients experienced recurrent laryngeal nerve damage. Parathyroid adenomas were found at the predicted site in all 40 patients with a clearly localizing sestamibi scan. Of the 31 patients who underwent radioguided parathyroidectomy, a single parathyroid adenoma was identified in 30 patients, and a double adenoma was found in 1 patient. Conversion to a standard procedure was necessary in 1 patient with a large adenoma. The average operating room time was 128 minutes for the radioguided procedure and 224 minutes for the standard exploration. The average incision length for radioguided parathyroidectomy was 3.3 +/- 0.7 cm. CONCLUSIONS: A clearly localizing sestamibi scan predicts that 97% of patients can undergo a successful and safe minimally invasive radioguided parathyroidectomy that requires less operative time than the standard exploration.