Multiple parathyroid adenomas: report of thirty-three cases

An increasing number of patients with primary hyperparathyroidism are found to have two or three enlarged parathyroid glands. Of 865 patients successfully operated on by one surgeon (J.N.A.), multiple enlarged parathyroid glands (adenomas) were found and resected in 33 cases (3.8%), with resulting normocalcemia lasting from 1 to 22 years (mean 5.8). Twenty-nine patients had two adenomas and four had three adenomas. In 28 patients the multiple adenomas were synchronous. Twenty-five patients underwent removal of all of the enlarged parathyroid glands in one operation; in three patients one adenoma was removed, reoperation for persistent hypercalcemia was performed, and a second adenoma was resected with cure. In five patients one adenoma was removed, normocalcemia ensued for 3 to 18 years, and a second (metachronous) adenoma occurred and was resected successfully. Although 10 of 70 enlarged parathyroid glands removed were labeled hyperplasia, cure in all but one of our patients by selective resection of only enlarged parathyroid glands emphasizes the unreliability of histologic criteria in differentiating between parathyroid adenoma and hyperplasia. Based on this study, we support the existence of multiple adenomas and advocate removal of only macroscopically enlarged parathyroid glands in patients with primary hyperparathyroidism.     

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.     

First cervicotomy for primary hyperparathyroidism. Argument against preoperative imaging

The sensitivity of various pre-operative imaging methods for enlarged parathyroid glands ranges between 40 and 80%. These dismal results can be explained by the limits of resolution and uneven specificity of the methods and by parathyroid ectopias. Conversely, in primary hyperparathyroidism (PHT), multiple gland enlargement occurs in 12-30% of cases and therefore, even a positive imaging study can overlook a second enlarged gland. A prospective study conducted in 34 patients, all successfully operated, confirmed the lack of value of pre-operative imaging before a first neck exploration, with a sensitivity of 33 to 80%, depending on the method.     

Anatomical heterogeneity of parathyroid glands in posttransplant hyperparathyroidism

Successful renal transplantation may be complicated by persistent hyperparathyroidism due to diffuse parathyroid hyperplasia remaining from a prolonged period of pretransplant chronic renal failure treatment. Posttransplant hyperparathyroidism is distinct from primary hyperparathyroidism, being characterized by multiple gland involvement and diffuse hyperplasia rather than a single adenoma. The gross pathologic anatomy of the parathyroid glands was assessed in 17 successful renal transplant recipients. Individual and total gland volumes were measured at the time of total parathyroidectomy and forearm reimplantation. Parathyroid hyperplasia was heterogenous in both location and gland size. Right-sided glands were enlarged more than left-sided ones. Subjects with primary tubulointerstitial disease exhibited greater hyperplasia than patients with glomerular disorders. Clinicians should be aware of the heterogeneity of the gland enlargement in patients with diffuse parathyroid hyperplasia, so that these patients are not misdiagnosed as suffering from adenomatous parathyroid disease.     

Clinical characteristics and surgical treatment of sporadic primary hyperparathyroidism with emphasis on chief cell hyperplasia

In 570 patients with sporadic primary hyperparathyroidism, the age, sex, symptoms, and preoperative serum calcium values were related to the histopathologic diagnoses, operative findings, and the extent and outcome of parathyroid surgery. Renal stone formation was especially prevalent in younger patients with slight hypercalcemia and parathyroid chief cell hyperplasia, whereas neuromuscular and psychiatric disturbances were overrepresented among older women with higher serum calcium values. Serum calcium concentration was inversely correlated to the proportional incidence of chief cell hyperplasia and positively correlated to the glandular weight of both adenomas and hyperplasias. Glandular size was markedly irregular in chief cell hyperplasia, with increased gland weights of no more than two glands in 78% of patients. During follow-up, for as long as 27 years, normocalcemia was obtained in 91% of patients with adenomas, with failures mainly depending on difficulties in identifying the parathyroid glands. The rate of normocalcemia was lower (80%) among patients with hyperplasia, but an inability to visualize the glands was not a major cause of failure. In patients with hyperplasia with asymmetric and more markedly enlarged glands, it appeared sufficient to remove only the enlarged glands, whereas the findings advocated a subtotal 3- to 3.5-gland resection in patients with more symmetrically or less enlarged hyperplastic glands.     

Primary hyperparathyroidism in the 1990s. Choice of surgical procedures for this disease.

Many advances have occurred in recent years in the diagnosis, localization, and treatment of primary hyperparathyroidism. Several different operative choices for primary hyperparathyroidism also have been proposed--a unilateral approach versus the standard bilateral parathyroid exploration. The unilateral approach is based on the concept that if an enlarged parathyroid gland and a normal gland are found on the first side of the neck that is explored, then this is an adenoma and the second side should not be explored. Only if both glands on the initial side are recognized to be abnormal is the second side explored. The theoretical advantages of this unilateral approach are a decrease in operative morbidity rates--hypoparathyroidism and nerve injuries--and a decrease in operative time. Furthermore, proponents argue that if persistent hyperparathyroidism occurs, the second side can be easily explored because it was previously untouched. In the hands of several expert parathyroid surgeons, excellent results have been achieved. However, the unilateral approach has a number of disadvantages. It places considerable pressure on the surgeon and pathologist, for they have only one parathyroid gland other than the large one to examine. There is a significant potential risk of missing double adenomas or asymmetric hyperplasia because the second, ipsilateral parathyroid gland may appear normal or near normal in these conditions. This could lead to an increased incidence of persistent or recurrent hyperparathyroidism. Furthermore, a significant reduction of operative time may be questioned, especially when the time for performing special fat stains, which often are performed with unilateral explorations, is added. Finally, even if the intent is to perform a unilateral exploration, a bilateral exploration will be necessary about half of the time. The authors strongly recommend a bilateral parathyroid exploration for all patients undergoing an initial parathyroid operation. In cases of adenoma, bilateral visualization of normal parathyroid glands and careful biopsy of only one of them will minimize hypoparathyroidism. This operative approach will lead to better results, especially for the less experienced parathyroid surgeon.     

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.     

Enlarged parathyroid glands discovered in normocalcemic patients during thyroid surgery

BACKGROUND: This is a retrospective study analyzing data of normocalcemic patients with enlarged parathyroid glands discovered during thyroid surgery and comparing it with data of patients operated on for proved primary hyperparathyroidism. METHODS: The records of patients with enlarged parathyroid glands (group 1) and those with primary hyperparathyroidism (group 2) were reviewed. RESULTS: There were 11 patients in group 1 and 123 patients in group 2. Enlarged parathyroid glands identified at thyroid surgery were lighter and developed in younger patients. Biochemistry and pathology revealed that these were less hyperfunctioning. Sex, number of diseased glands per patient, and cell type were not statistically different between the 2 groups. CONCLUSIONS: Enlarged parathyroid glands discovered at the time of surgery are mildly hyperfunctioning. They may represent an early pathologic stage responsible for overt primary hyperparathyroidism. We recommend removal of enlarged parathyroid glands found during thyroid operation in normocalcemic patients as long as at least 1 normal parathyroid gland remains.     

The rationale against routine subtotal parathyroidectomy for primary hyperparathyroidism

Our therapeutic approach to the treatment of primary hyperparathyroidism has been the resection of only the abnormally enlarged parathyroid gland, the normal-appearing parathyroids being left intact. During the past twenty-five years we have operated on 292 patients with primary hyperparathyroidism. In all cases the serum calcium levels returned to within normal limits during the immediate postoperative period, and there were no instances of permanent hypoparathyroidism. To determine the long-term efficacy of this therapeutic approach, a retrospective study of 101 patients operated on for primary hyperparathyroidism during a nine year period from July 15, 1965 through June 30, 1974 was made. Of the 101 patients, eight were dead and nine could not be located. Of the remaining eighty-four patients, only two required reoperation because of recurrent hypercalcemia; one had MEA-I and eventually three and a half glands were removed, and the other had recurrent hypercalcemia after a three year normocalcemic interval, and after a second operation with resection of an enlarged parathyroid gland, he has remained normocalcemic. The other eighty-two patients (97 per cent of those reevaluated and 82 per cent of the total operated on) have remained symptom-free and normocalcemic for periods ranging from three to twelve years. Only one patient (if we exclude the patient with MEA-I) has elevated serum parathormone levels with borderline levels of serum calcium. Our results suggest that the optimal surgical treatment of primary hyperparathyroidism, except for cases of MEA, is resection of only the abnormally enlarged parathyroid glands after exploration and identification of all four glands in every case. If all four glands are enlarged, three and a half should be resected.     

Spontaneous infarction of parathyroid adenoma: Case report and literature review

A patient with asymptomatic primary hyperparathyroidism who spontaneously became normocalcemia is reported. The only significant finding was that of pain and tenderness in the enlarged parathyroid gland 2 weeks prior to surgery. This was due to a recent infarction of a parathyroid adenoma.     

The clinical significance and anatomic distribution of parathyroid double adenomas

BACKGROUND: Parathyroid double adenomas are reported to occur in 3% to 12% of cases of primary hyperparathyroidism, but the very existence of double adenomas has been controversial. This study was undertaken to evaluate the clinical significance and anatomic distribution of parathyroid double adenomas. STUDY DESIGN: The medical records of 384 consecutive patients who underwent operation for primary hyperparathyroidism were reviewed. RESULTS: A total of 27 patients (7%) were found to have double parathyroid adenomas. Intraoperative parathyroid hormone (PTH) levels were measured in each case. Two enlarged hypercellular parathyroid glands were identified in 6 possible configurations: 10 both superior, 3 both inferior, 5 both right, 3 both left, 5 right superior and left inferior, and 1 left superior and right inferior. There was preferential distribution to the bilateral superior position (p = 0.008). In all patients intraoperative PTH levels dropped by at least 50% from baseline and into the normal range after removal of both abnormal parathyroid glands. All patients remain normocalcemic 1 to 26 months postoperatively. Two patients have persistently elevated PTH values with normal serum calcium levels. CONCLUSIONS: The drop in intraoperative PTH levels and maintenance of normocalcemia postoperatively confirm previous reports that double adenomas do exist and are not simply missed cases of four-gland hyperplasia. Their incidence is more than would be expected by chance alone. The preferential occurrence of bilateral superior double adenomas suggests the possibility that these may represent hyperplasia of parathyroids arising from the fourth branchial pouch rather than isolated neoplastic events.     

The relation of serum calcium and immunoparathormone levels to parathyroid size and weight in primary hyperparathyroidism

This study was designed to determine whether the serum calcium or immunoparathormone (iPTH) level would be of value in predicting the size or weight of the parathyroid gland in patients with single-gland enlargement caused by primary hyperparathyroidism. Ninety-two patients who underwent parathyroidectomy with removal of a single enlarged gland at the North Carolina Memorial Hospital (1974 to 1984) were reviewed. The preoperative calcium and immunoparathormone levels were correlated to the weight and calculated volume of the removed gland. The calcium level was found to be significantly associated with parathyroid gland weight and volume (p less than 0.001), as determined by linear regression analysis. Despite the statistical association, the correlation coefficient (calculated with the Pearson correlation matrix) was low, 0.16 for the relation of calcium to gland weight and 0.25 for the relation of calcium to calculated gland volume. The calculated coefficients of correlation of iPTH (three different assays) to gland weight and volume were similarly low. These findings demonstrate a variable relationship between the preoperative serum calcium level or the iPTH level to the weight or volume of the enlarged hyperfunctioning parathyroid gland. Identification of the pathologic parathyroid gland(s) in primary hyperparathyroidism cannot be based on a perceived relation of preoperative calcium or iPTH levels to the size of the enlarged glands.     

Prospective evaluation of the efficacy of technetium 99m sestamibi and iodine 123 radionuclide imaging of abnormal parathyroid glands.

BACKGROUND. Technetium 99m sestamibi is an isonitrile radionuclide imaging agent that, when used with subtraction iodine 123 thyroid scans, has the potential for imaging abnormal parathyroid glands. METHODS. We prospectively evaluated 20 patients with hyperparathyroidism to study the efficacy of Tc 99m sestamibi and 123I subtraction radionuclide scanning for the imaging of abnormal parathyroid glands. All patients underwent neck exploration and histologic confirmation of all parathyroid glands identified. RESULTS. The solitary adenomas in 11 of 16 patients with primary hyperparathyroidism were localized with sestamibi scans. The scans in four of five patients with diffuse parathyroid hyperplasia showed bilateral localization consistent with enlarged glands. The fifth patient previously underwent a subtotal parathyroidectomy, and a fifth supernumerary gland was localized with the sestamibi scan. Four patients had hyperparathyroidism related to kidney disease. Three of these had bilateral localization of enlarged glands. The fourth patient had undergone two previous operations, and a fifth supernumerary gland was localized with the sestamibi scan. CONCLUSIONS. The preliminary data indicate that Tc 99m sestamibi in combination with 123I radionuclide scanning may be useful in the preoperative localization of abnormal parathyroid glands. This technique localized all of the solitary adenomas that were subsequently resected, and in two reoperative cases it identified the remaining solitary gland causing persistent hypercalcemia.     

Results of operative treatment of 615 patients with primary hyperparathyroidism

This is a report of 615 patients who were operated on for primary hyperparathyroidism during the 20 years from 1950 to 1979. There were twice as many females in the series as males, mainly because of a sharp rise in the incidence in females over the age of 45 years. Identification of all parathyroid glands and confirmation by frozen section was always attempted. Only macroscopically enlarged glands were removed, regardless of histologic findings. Enlargement of 1 gland was found in 433 patients, of 2 glands in 106, and of 3 glands in 43. In 33 patients all glands were enlarged. Bilateral exploration of the neck is mandatory in order to prevent persistent hyperparathyroidism. An abnormal location of parathyroid glands was found in 263 patients; location within the thymus was the most frequent. Most ectopically located parathyroids can be removed through the neck. Sternotomy gave disappointing results; in only 3 of 9 patients was an enlarged parathyroid found. Persistent hyperparathyroidism necessitating reoperation occurred in 25 patients. The results of reoperation were not as favorable as those of primary operations and gave rise to more complications, especially inadvertent removal of all parathyroid tissue. The mean follow-up time was 5.6 years. During this period no patient developed true recurrent hyperparathyroidism arising in a previously identified normal appearing gland. Therefore, we advise removal of only those glands that are macroscopically enlarged.     

DNA patterns in parathyroid disease predict postoperative parathyroid hormone secretion

Flow cytometric analysis of the nuclear deoxyribonucleic acid (DNA) content of parathyroid glands excised from patients with hypercalcemic hyperparathyroidism has identified three distinct DNA patterns. The most frequent pattern showed a high percentage of cells with tetraploid DNA, which indicated an increase in the G2 and M phase of the cell cycle. Thirty-four patients were found to have abnormal tetraploid DNA content. One patient had a normal diploid pattern, and seven were found to have an aneuploid DNA population in their excised parathyroid glands. This unexpected finding of aneuploid DNA appears to be an unique feature of these endocrine glands because they have no histologic or clinical characteristics of malignant change. All patients have remained normocalcemic and clinically well after excision of only grossly enlarged glands. Postoperative parathyroid hormone (PTH) levels were correlated in 17 patients with DNA analyses of biopsy specimens from 30 normal-sized glands which were left in situ. Seven patients with elevated PTH postoperatively had high tetraploid or aneuploid DNA in all 13 glands from which biopsy specimens had high tetraploid or aneuploid DNA in all 13 glands from which biopsy specimens had been taken. In 10 patients with normal PTH levels, six had normal diploid patterns, whereas four had high tetraploid DNA in their gland biopsy specimens. DNA content present in biopsy specimens of normal-sized, in situ glands was predictive (p less than 0.042) of parathyroid gland secretory activity. These findings suggest that the stimulus for parathyroid gland hyperfunction often affects more than a single enlarged gland and persists after clinical cure, as shown by a more rapid cell turnover in some remaining glands and continued hypersecretion of hormone.     

Radioguided parathyroidectomy is equally effective for both adenomatous and hyperplastic glands

OBJECTIVE: To determine the utility of radioguided parathyroidectomy for patients with hyperparathyroidism, we studied the properties of 180 resected, hyperfunctioning parathyroid glands. SUMMARY AND BACKGROUND DATA: Radioguided resection of hyperfunctioning parathyroid glands has been shown to be technically feasible in patients with parathyroid adenomas. Radioguided excision may obviate the need for intraoperative frozen section because excised parathyroid adenomas uniformly have radionuclide ex vivo counts >20% of background. The feasibility and applicability of radioguided techniques for patients with parathyroid hyperplasia are unclear. METHODS: Between March 2001 and September 2002, 102 patients underwent neck exploration for primary (n = 77) and secondary/tertiary (n = 25) hyperparathyroidism. All patients received an injection of 10 mCi of Tc-99m sestamibi the day of surgery. Using a gamma probe, intraoperative scanning was performed, looking for in vivo radionuclide counts > background to localize abnormal parathyroid glands. After excision, radionuclide counts of each ex vivo parathyroid gland were determined and expressed as a percentage of background counts.RESULTS Although patients with single adenomas had higher mean background radionuclide counts, the average in vivo counts of all enlarged glands were higher than background. Notably, in vivo counts did not differ between adenomatous and hyperplastic glands, suggesting equal sensitivity for intraoperative gamma detection. Ectopically located glands were identified in 22 cases and all were accurately localized using the gamma probe. Postresection, mean ex vivo radionuclide counts were highest in the single parathyroid adenomas and lowest in hyperplastic glands. Importantly, in all hyperplastic glands, the ex vivo counts were >20%. CONCLUSIONS: In patients with hyperparathyroidism, radioguided surgery is a sensitive adjunct for the intraoperative localization of both adenomatous and hyperplastic glands. In this series, all 180 enlarged parathyroids were located with the gamma probe. We have also shown that the ">20% rule" for ex vivo counts not only applies to parathyroid adenomas but also to hyperplastic glands. Therefore, radioguided resection is equally effective and informative for both adenomatous and hyperplastic glands.     

Late parathyroid function after successful parathyroidectomy guided by intraoperative hormone assay (QPTH) compared with the standard bilateral neck exploration

BACKGROUND: Controversy continues between bilateral neck exploration and limited parathyroidectomy. One approach depends on gland size and histopathologic factors; the other approach limits excision to only hypersecreting glands. Both have excellent early operative success, but late recurrence rates with limited exploration are unknown. METHODS: Three hundred twenty consecutive patients with primary hyperparathyroidism were followed 6 to 313 months after successful parathyroidectomy. One hundred seventy-six patients had bilateral neck exploration with excision of enlarged glands (group I); 144 patients had glands excised based on hyper-secretion (group II). Calcium and intact parathyroid hormone (iPTH) levels were measured yearly. Parathyroid gland hypersecretion was determined by elevated iPTH levels. RESULTS: In group I, 1 gland was excised in 160 patients (91%); 19 of 176 patients (11%) had elevated iPTH levels. In group II, 139 patients (97%) had 1 gland excised; 19 of 144 patients (13%) had high iPTH levels. The number of patients with more than 1 gland excised in group I (9%) is 3 times higher than in group II (3%) (P <.05). There was no significant difference in the incidence of recurrent hyperfunctioning glands between the 2 different operative approaches (chi-squared test). CONCLUSIONS: Late parathyroid gland function was comparable with both approaches. Multiple gland excision based on size alone may lead to excision of normal functioning glands.     

Limited versus radical parathyroidectomy in familial isolated primary hyperparathyroidism

BACKGROUND: Familial isolated primary hyperparathyroidism (FIHPT) is characterized by earlier onset, higher incidence of multiglandular disease, and higher recurrence rate when compared with sporadic primary hyperparathyroidism. Excision of 3.5 or 4 glands with autotransplantation has been recommended; however, these approaches lead to permanent hypoparathyroidism in 13% to 41% of patients. It is reported that many patients with FIHPT return to normocalcemia after single-gland excision. The use of preoperative localization and intraoperative parathyroid hormone assay permits limited resection of only hypersecreting glands. We report the outcome of this operative approach. METHODS: Fifteen consecutive patients with FIHPT underwent limited parathyroidectomy with resection guided by intact parathyroid hormone secretion in 2 university centers. Patients were followed up postoperatively for serum calcium and intact parathyroid hormone levels. RESULTS: With an operative success of 93%, 14 patients had only single-gland excision and 80% had unilateral neck exploration. All initial patients had their hypercalcemia corrected. In 4 reoperations, permanent hypoparathyroidism occurred in 2 patients. One recurrence was observed in 40 (8-122) months of follow-up. CONCLUSION: Limited parathyroidectomy allows successful single-gland excision in many patients with FIHPT, thus decreasing the risk of hypoparathyroidism. In these patients, a low incidence of hypoparathyroidism may be preferable to the possibility of late recurrence.     

Parathyroid surgery: the role of chief cell intracellular fat staining with osmium carmine in the intraoperative management of patients with primary hyperparathyroidism

The surgeon's gross evaluation, the hematoxylin and eosin stain, which assesses extracellular fat, and a new intracellular fat stain, osmium carmine, were comparatively evaluated in 30 consecutive patients who underwent surgery for primary hyperparathyroidism. The surgeon's gross judgment of enlarged and normal parathyroid tissue resulted in the correct functional assessment in 98% and 97% of the glands, respectively. The surgeon's functional assessment was correct in seven of 10 parathyroid glands that were considered by gross examination to be slightly enlarged (50 to 80 mg). The osmium carmine intracellular fat stain provided a correct functional assessment in all 10 of these glands. The osmium carmine stain also appears to have a role in providing scientific quantitative data to limit operations in patients who have a parathyroid adenoma to removal of the adenoma and biopsy of a grossly normal gland that demonstrates normal intracellular fat. Only one side of the neck was explored in 11 patients who fulfilled these criteria. There has been no persistent or recurrent hypercalcemia in these patients.     

Parathyroidectomy by elective route with perioperative measurement of parathyroid hormone. Report of 80 cases

STUDY AIM: The aim of this study was to report a series of 80 patients treated by unilateral neck exploration for a sporadic primary hyperparathyroidism. PATIENTS AND METHOD: Between April 1992 and November 1998, 80 patients (65 women and 15 men, mean age: 63.5 years) with a single gland enlargement localized by ultrasonography, were operated on through a short unilateral neck incision, under general anesthesia in 72 cases and local in eight cases. The enlarged gland was removed with intraoperative pathological examination and intraoperative monitoring of parathyroid hormone. RESULTS: Mean duration of surgery was 25 minutes. There was no postoperative mortality or morbidity. Mean duration of hospital stay was two days. The enlarged gland was an adenoma in 75 cases and an hyperplasia in five. Adequate intraoperative parathyroid hormone decrease was observed. Postoperative calcemia was normal in 78 patients (97.5%). Among 76 surviving patients, with a 31-month follow-up, there was only a suspicion of persistent hyperparathyroidism in two patients. CONCLUSIONS: Minimal invasive approach by unilateral neck exploration may be performed with safety and efficiency in patients with a single gland enlargement under intraoperative monitoring of parathyroid hormone.