Is extensive surgery really necessary in patients with parathyroid carcinoma? Single-centre experience and a brief review of the literature.

AIM: Parathyroid carcinoma (PC) represents a rare cause of primary hyperparathyroidism (PHPT). In this paper, among patients who underwent surgery for PHPT, we compared those with benign parathyroid disease with those affected by PC in terms of demographic and preoperative biochemical features. Moreover, we singularly described all 10 cases of PC treated at our Institution (including a case that occurred in a patient with tertiary hyperparathyroidism) and a brief review of the literature. MATERIAL AND METHODS: Patients undergoing surgery for PHPT in our Unit between 2003 and 2018 were retrospectively analysed. They were divided into two groups: Group A (benign parathyroid disease), Group B (PC). The case of PC that occurred in the patient with tertiary hyperparathyroidism was not included into the two groups. RESULTS: Three hundred and eight patients were included: 299 in Group A and 9 in Group B. The mean preoperative serum PTH value and mean preoperative serum calcium level were significantly higher in Group B than in Group A (P = 0.018, P = 0.027; respectively). Including the case of PC that occurred in the patient with tertiary hyperparathyroidism, 10 patients with PC were treated at our Institution. Among these, 3 underwent a re-exploration. Disease recurrence occurred in 1 (10%) patient, who developed a local recurrence and distant metastases. CONCLUSIONS: In the presence of PHPT characterized by particularly high preoperative levels of serum PTH and calcium this malignancy should be suspected. On the basis of our experience, we believe that extensive surgery is not always necessary. KEY WORDS: Hyperparathyroidism, Parathyroid carcinoma, Parathyroid surgery.

Monoclonal/polyclonal PAX-8, PTH and GATA3 immunohistochemistry in parathyroid lesions.

BACKGROUND: Parathyroid gland (PG) is an endocrine organ which may display different immunohistochemical stainings with chief cells and oxyphilic cells in normal as well as hyperplasic/tumoral lesions. PURPOSE: In this study, we aimed to identify the demographic properties and diagnostic value of the GATA3 antibody, which is a transcription factor in addition to PTH, and of PAX-8 (monoclonal and polyclonal) antibody. METHODS: We have analyzed in detail the cellular components and staining intensities of 46 adenomas all of which contained parathyroid rims, 12 hyperplasia and 5 adjacent non-neoplastic thyroidectomy materials (63 patients, 114 tissues). RESULTS: While no staining was identified in the thyroid tissue, cytoplasmic PTH immunoreactivity was observed in all (100%) normal parathyroid tissues, rim of PGs and hyperplasia, and in 43/46 cases (93.4%) of adenomas. Adenoma and hyperplasia were less stained than normal PG (p < 0.05). We detected GATA3 staining in all cases except for the thyroid (100%). Weak positivity (1+) was most apparent in adenoma cases (p < 0.05). Monoclonal PAX-8 immunoreactivity was not identified in any normal parathyroid tissue and rim of PG but positive immunoreactivity was detected in 83.3% of hyperplasia cases (10/12), 84.8% of adenoma (39/46) and 100% of thyroid tissues (5/5) (p < 0.05). However, polyclonal PAX-8 immunoreactivity was detected in one normal parathyroid tissue (1/5) and seven (7/46) rim of PGs. In cases of hyperplasia and adenoma, positive immunoreactivity was 75% (9/12) and 74% (34/46), respectively. CONCLUSION: In conclusion, we have observed that PTH and GATA3 constitute a much more reliable and sensitive marker for parathyroid and are stained less in adenomas. While monoclonal PAX-8 (MRQ-50) never stains normal parathyroid and rim of PGs, it may help in the differential diagnosis of proliferated parathyroid lesions as a considerably sensitive and relatively specific marker by staining hyperplasic parathyroid, adenomas and the thyroid.

Parathyroid cysts: experience of a rare phenomenon at a single institution.

BACKGROUND: Parathyroid cysts are relatively uncommon lesions and are often misdiagnosed. We evaluate our experience in the diagnosis of and therapy to correct parathyroid cystic lesions. METHODS: We retrospectively reviewed a series of 32 patients with parathyroid cysts who were admitted to our department between July 2011 and November 2016. Clinical pathological features of the patients, including age, gender, location, size, ultrasonography, histopathology, surgery, and follow-up, were analyzed. RESULTS: There were 22 female and 10 male participants with a median age of 46.7 years old (27-76 years old). Only two cysts were found in the superior mediastinum. The rest were located under the lower pole of the thyroid. All of the patients underwent ultrasonography scans and serum parathyroid hormone (PTH) assays. Three patients had elevated serum PTH levels, and they were further scanned with Tc99m sestamibi as functional cysts. In 29 cases of nonfunctional cysts, 3 cases were preoperatively diagnosed by cystic aspiration with PTH detection. The rest were diagnosed by postoperative immunopathology. All of the patients underwent cystectomy, and 24 patients also underwent thyroidectomy. There was a significant difference in cyst diameter size between the cystectomy alone and cystectomy with thyroidectomy groups (4.0 ± 2.0 vs 1.5 ± 1.0 cm; p < 0.05). No participant experienced recurrence during the median 36 months of follow-up. CONCLUSIONS: Cystic lesions located under the lower pole of the thyroid gland should be considered to have originated at the parathyroid gland. Cystic aspiration with PTH detection or postoperative immunopathology can lead to a definitive diagnosis. Cystectomy is still a commonly used and effective treatment.

Endocrine function over time in patients with myotonic dystrophy type 1.

BACKGROUND AND PURPOSE: Patients with myotonic dystrophy type 1 (DM1) have an increased incidence of endocrine dysfunction. In this study, the temporal evolution of endocrine dysfunction in patients with DM1 was investigated. METHODS: Endocrine function was assessed in 68 patients with DM1, in whom endocrine function had been followed, on average, for 8 years. The endocrine function was assessed by measuring the concentration of hormones and metabolites in blood and by validating libido with questionnaires. RESULTS: At baseline, 30 of the 68 patients presented with at least one hormonal dysfunction. When re-evaluated after 8 years, 57 of 68 patients had endocrine dysfunction. Diabetic patients had increased from one to four. At follow-up, hyperparathyroidism occurred in 25% and abnormal thyroid-stimulating hormone in 21%, compared with 14% and 9% at baseline. Sixteen of 33 men had increased luteinizing hormone levels compared with seven at baseline. CONCLUSIONS: Our findings show that endocrine abnormalities amongst patients with DM1 increase over time. Based on these findings it is suggested that correctable endocrine abnormalities should be monitored periodically in this patient group.

The role of thyroid and parathyroid metabolism disorders in the etiology of sudden onset dizziness.

BACKGROUND: The aim of this study was to evaluate thyroid and parathyroid functions as a cause of sudden onset dizziness (SOD) in patients who were admitted to the Emergency Department (ED). MATERIAL AND METHODS: This study was conducted prospectively in 100 patients with sudden onset dizziness (SOD) admitted to the ED. Neurologic, ear-nose-throat, detailed neck examinations, serum calcium levels, thyroid function tests (TFT), and parathormone and thyroid ultrasounds were performed on all patients in our study. RESULTS: Thirty-seven (37%) females and 63 (63%) males were included in this study. Four patients (4%) had elevated serum TSH levels, 6 (6%) had decreased serum fT3 levels, 10 (10%) had decreased serum fT4 levels, 2 (2%) had elevated serum fT4 levels, and 2 (2%) had elevated serum parathormone levels. In 4 (4%) patients, the serum calcium levels were lower than normal, and 2 (50%) of these patients had symptomatic hypocalcemia. Thyroid ultrasound examinations showed multinodular goiter in 28 (28%) patients, 2 (2%) patients had thyroiditis, 12 (12%) had an isolated unilateral nodule, and 58 (58%) had normal thyroid tissues. CONCLUSIONS: We suggest that detailed neck examination, TFT, and thyroid ultrasound examination should be considered in the diagnostic algorithms of SOD to provide rapid diagnosis and proper treatment for a patient in the ED.

Intraoperative parathyroid hormone monitoring corroborates the success of parathyroidectomy in children.

OBJECTIVE: To assess the efficacy of intraoperative parathyroid hormone (PTH) monitoring in evaluating the outcome of parathyroidectomy in pediatric patients. METHODS: Intraoperative PTH monitoring during parathyroidectomy was performed in five children (3M, 2F); three had parathyroid adenomas (single gland disease) and two had primary hyperplasia. One patient had undergone two previous surgical interventions to remove the parathyroid glands, but the PTH levels had remained high with persistence of symptoms. Immunoradiometric analysis was used for PTH measurements. Preoperative PTH values were obtained to monitor the baseline levels. Serum samples were collected 20 minutes after removal of the adenoma/parathyroid gland(s) and PTH levels were compared with preoperative values. Specimens were also confirmed by frozen sectional examination. RESULTS: Mean age of the patients was 11 years (range: 3 months-16 years). Mean preoperative PTH values were 633.3±579 pg/mL (range: 143-1300 pg/mL). Intraoperative values decreased to 18.7±5.5 pg/mL (range: 8-27 pg/mL) following removal of the gland(s). Normal calcium levels were achieved with adequate management following surgery. One patient (with multiple surgeries and found to have an ectopic parathyroid gland) had hungry bone syndrome after the operation and was treated successfully. There were no major complications. All patients maintained normal calcium/phosphorus levels in the follow-up period, ranging from 2 to 5 years. CONCLUSION: An ectopic parathyroid gland or another undetected adenoma can be overlooked during surgery. Owing to the short life of the hormone, intraoperative PTH monitoring to determine PTH clearance proved to be a feasible marker for adequacy and safety of surgery and "cure".

Usefulness of PTH measurements in FNAB washouts in the identification of pathological parathyroids--analysis of the factors that influence the effectiveness of this method.

INTRODUCTION: The aim of this investigation was to assess the usefulness of the measurement of PTH concentration in the material obtained during FNAB (PTH-FNAB) in the identification of pathological parathyroids in patients with frequently coexisting thyroid abnormalities (nodular goitre, chronic thyroiditis, previous thyroidectomy). Additionally, the influence of the size of goitre, parathyroid localisation and size on the results of PTH-FNAB measurement was examined. MATERIAL AND METHODS: Fifty patients with primary hyperparathyroidism and sonographically detected focal lesion that was suggestive of parathyroid gland were included in this study. PTH-FNAB results were correlated with the outcome of routine cytological examination and biochemical indices of hyperparathyroidism, SPECT-CT (33 patients) and histopathological examination (20 patients). RESULTS: Positive PTH-FNAB was observed in 80% of patients, and in more than 70% of persons with non-diagnostic smears or smears 'contaminated' with thyroid follicular cells. In the group of operated patients, sensitivity of PTH-FNAB (95.0%) was higher than SPECTCT (64.3%, p < 0.05). Presence of nodular goitre and/or chronic thyroiditis exerts a two times stronger negative effect on percentage of negative results of SPECT-CT than of PTH-FNAB. On the other hand, lower frequency of positive PTH-FNAB but not SPECT-CT was observed when the thickness of the thyroid was ≥ 20 mm (50% v. 87.5%, p < 0.05) and when the thickness of a lesion suspected of parathyroid pathology was ≤ 5 mm (66.7% v. 93.3%, p < 0.05). CONCLUSIONS: In patients with thyroid abnormalities, PTH-FNAB measurements show advantages over routine biopsy and SPECT-CT in the identification of typically located pathological parathyroids.

Circulating sclerostin in disorders of parathyroid gland function.

CONTEXT: Sclerostin, a protein encoded by the SOST gene in osteocytes and an antagonist of the Wnt signaling pathway, is down-regulated by PTH administration. Disorders of parathyroid function are useful clinical settings to study this relationship. OBJECTIVE: The objective of the study was to evaluate sclerostin in two different disorders of parathyroid function, primary hyperparathyroidism and hypoparathyroidism, and to analyze the relationship between sclerostin and PTH, bone markers, and bone mineral density. DESIGN: This is a cross-sectional study. SETTING: The study was conducted at a clinical research center. PATIENTS: Twenty hypoparathyroid and 20 hyperparathyroid patients were studied and compared to a reference control group. RESULTS: Serum sclerostin was significantly higher in hypoparathyroid subjects than in hyperparathyroid subjects (P < 0.0001) and controls (P < 0.0001). PTH was negatively associated with sclerostin, achieving statistical significance in hypoparathyroidism (r = -0.545; P = 0.02). The bone turnover markers, cross-linked C-telopeptide of type I collagen (CTX) and amino-terminal propeptide of type I collagen (P1NP), were differently associated with sclerostin according to the parathyroid disorder. In primary hyperparathyroidism, bone turnover markers were associated negatively with sclerostin (for P1NP, r = -0.490; P = 0.03). In hypoparathyroidism, bone turnover markers were associated positively with sclerostin (for CTX, r = +0.571; P = 0.01). Although there was no significant correlation between bone mineral density and sclerostin in either parathyroid disorder, there was a significant positive relationship between sclerostin and bone mineral content in hypoparathyroidism. CONCLUSIONS: The results are consistent with the hypothesis that PTH is a regulator of sclerostin in human disorders of parathyroid function. In addition, the results suggest that bone mineral content may be another factor that influences sclerostin.

Hormone replacement after thyroid and parathyroid surgery.

BACKGROUND: Hypothyroidism and hypocalcemia are common after thyroid and parathyroid surgery. In this article, the authors provide clinically-oriented recommendations to help surgeons, general practitioners, internists, and endocrinologists give their affected patients adequate hormone replacement therapy. METHODS: Selective evaluation of original articles and reviews that were retrieved by a PubMed search over the years 1980 to 2010, as well as of the recommendations of medical societies including the Endocrine Society (USA), the German Society for Endocrinology (Deutsche Gesellschaft für Endokrinologie), and the American and European Thyroid Associations. RESULTS: Important issues in L-thyroxine replacement therapy include: the selection of the hormone preparation (T4 or T4/T3), combination with iodine (yes/no), the definition of therapeutic TSH ranges (particularly after surgery for thyroid cancer), the extent of remaining thyroid tissue after goiter surgery and its significance, underlying diseases, and drug interactions. The major issues in the treatment of postoperative hypoparathyroidism are: the selection of suitable calcium and vitamin D preparations, the definition of therapeutic goals, the treatment of hypercalciuria and hyperphosphatemia, and the option of recombinant parathormone therapy. CONCLUSION: Effective treatment requires an appropriate choice of medication and an understanding of its pharmacokinetics as well as of the possible effects of the patient's underlying disease, comorbidities, and other medications on its absorption and metabolism.

[B-, H- and L-cathepsin-like activity in blood plasma of patients with diseases of the thyroid, parathyroid and adrenal glands].

B-, H- and L-catepsine-like activity regarding Na-benzoyl-D,L-arginine-4-nitroanilide, L-leucine-4-nitroanilide and azocasein was studied in the blood plasma of patients with different diseases of thyroid, parathyroid and adrenal glands. It has been shown that the high H- catepsine-like activity confirming the activation of blood catepsin H secretion accompanied by the tissue growth under any pathology took place in the blood plasma of patients with all the above diseases. High B- catepsine-like activity in the blood plasma of patients with thyroid diseases was exceptionally fixed under the nodular forms of thyroid pathology, while the character of changes in L catepsine-like activity under these diseases was not so natural. In diaseses of the adrenal glands the changes in the B- and L-catepsine-like activity were only shown in the blood plasma of patients with cerebral layer tumors but not the gland cortex: B-catepsine-like activity increased in the blood plasma of patients with benign or malignant tumors, and L-catepsine-like activity decreased under benign tumor from chromaffin tissue. The established picture of changes in enzymatic activity in the blood plasma of patients does not allow to think that the determination of blood B- and L- catepsine-like activity can be recommended for obtaining additional information at diagnosis thyroid diseases.

The role of intraoperative measurement of parathyroid hormone in parathyroid surgery.

Technological developments have significantly contributed to the rapid evolution of the surgical management of parathyroid disorders. The ability to physiologically determine the intraoperative status of the patient is now possible through the assessment of changing levels of intact parathyroid hormone (PTH) during surgery. In most patients with primary hyperparathyroidism, this method provides biochemical confirmation of hyperfunctional gland removal, and is predictive of a eucalcemic state and surgical cure. Patients with renal-induced disease (excluding tertiary hyperparathyroidism) do not follow the same kinetic decline in PTH and are therefore less likely to benefit from this modality. An emerging population of patients with primary disease and lower baseline levels of intact PTH appear to demonstrate a greater likelihood of manifesting multiple gland disease and do not follow a consistently predictable kinetic degradation profile. Although this category of patients will require further investigation, potentially resulting in modification of the utility of intraoperative determination of PTH levels, it is clear that this modality represents a very powerful technique which has significantly enhanced the surgical treatment of parathyroid disease.

Novel criteria for parathyroid hormone levels in parathyroid hormone-guided parathyroid surgery.

CONTEXT: Novel criteria for decrease of perioperative parathyroid hormone measurement may improve the accuracy of perioperative quick parathyroid hormone (qPTH)-guided parathyroidectomy. OBJECTIVE: To assess overall cure rate based on conventional criteria (50% decline of qPTH). Perioperative qPTH levels were evaluated to determine novel criteria for successful parathyroid surgery. DESIGN: Analysis of perioperative qPTH measurement findings of all consecutive patients undergoing parathyroidectomy for hyperparathyroidism (72 with primary hyperparathyroidism and 28 with secondary or tertiary hyperparathyroidism or multiple endocrine neoplasia I/IIa disease). RESULTS: Measurement of qPTH (based solely on the criterion of greater than 50% decline of parathyroid hormone) in 72 patients with primary hyperparathyroidism (77 procedures) showed true-positive results in 69, false-positive results in 4, and true-negative results in 4 procedures. In our series, false-positive and true-negative results were associated with high postexcision levels. However, when qPTH declines of greater than 70% and 80% were used in cases of postexcision qPTH levels of 100 to 200 ng/L and greater than 200 ng/L, respectively, no false-positive results were observed. CONCLUSIONS: Through adherence to these novel criteria, reexploration of the neck could have been prevented in 29% of patients with primary hyperparathyroidism due to multiple gland disease. These novel criteria demand future evaluation to establish their value.

The spectrum of parathyroid gland dysfunction associated with the microdeletion 22q11.

OBJECTIVE: Clinical features associated with microdeletion of chromosome 22q11 (del(22)(q11)) are highly variable. Increased awareness of this condition is needed among specialists such as endocrinologists to reduce diagnostic delay and improve clinical care. The purpose of this study was to describe the phenotype of patients with del(22)(q11), focusing on parathyroid gland dysfunction. DESIGN AND METHODS: Charts of 19 patients, including one kindred of three, known to have del(22)(q11) diagnosed by fluorescence in situ hybridization (FISH) were reviewed from the register of the department of Medical Genetics. Major clinical features including hypoparathyroidism phenotype were collected. RESULTS: Parathyroid dysfunction was present in 8 out of 16 patients (50%). Six patients were diagnosed with overt hypoparathyroidism. Hypocalcemia manifested as laryngeal stridor within the first days of life (n = 3), seizures in infancy (n = 1) and adolescence (n = 2). The connection between hypoparathyroidism and diagnosis of del(22)(q11) was belated at the median age of 18 years. One patient had presented with transient neonatal hypoparathyroidism, and one patient had latent hypoparathyroidism. Within the kindred family, the phenotype variability including that of parathyroid dysfunction was as marked as between unrelated individuals. Standard karyotype failed to detect the deletion in 15 out of 19 cases. CONCLUSIONS: Abnormal parathyroid function in the del(22)(q11) ranges from severe neonatal hypocalcemia to latent hypoparathyroidism. Del(22)(q11) should be considered as a potential cause of hypocalcemia even in young adult. When suspected, the diagnosis requires investigation by FISH. Furthermore, long-term calcemia follow-up is needed in normocalcemic patients with del(22)(q11) because of the possible evolution to hypocalcemic hypoparathyroidism.

Prospective study of perioperative factors predicting hypocalcemia after thyroid and parathyroid surgery.

OBJECTIVE: To identify whether perioperative 1,25-dihydroxyvitamin D or parathyroid hormone (PTH) levels will predict the development of hypocalcemia after thyroid and parathyroid surgery. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: The study included 103 patients who underwent thyroid or parathyroid surgery between 2002 and 2004, with a comparison of the patients who underwent thyroid lobectomy (TL; n = 34), total thyroidectomy (TT; n = 27), parathyroid adenoma excision (PAE; n = 34), and subtotal parathyroidectomy for hyperplasia (SP; n = 8). MAIN OUTCOME MEASURES: Preoperative 1,25-dihydroxyvitamin D levels, number of patients requiring calcium replacement, and postoperative PTH and calcium levels. RESULTS: No patients in the TL or PAE group developed postoperative hypocalcemia that required calcium replacement. Six patients (22%) in the TT group and 3 patients (38%) in the SP group required calcium replacement for clinically significant hypocalcemia (P<.001). All patients who required calcium replacement had PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery. Among the patients with postoperative PTH levels of less than 15 pg/mL (1.6 pmol/L) 8 hours after surgery, no patients in the PAE group required calcium replacement, compared with 75% of patients in the TT and SP groups (P<.001). The patients in the TT group had significantly lower postoperative calcium levels than those in the TL (P<.001) or the PAE (P<.005) group. The patients in the TL group reached stable calcium levels significantly earlier than those in the other groups (15.8 hours after surgery; P<.05). There was no relationship between preoperative 1,25-dihydroxyvitamin D levels and postoperative calcium levels. CONCLUSIONS: Preoperative 1,25-dihydroxyvitamin D levels were not predictive of postoperative calcium levels. Patients who undergo PAE or TL are at extremely low risk for requiring calcium replacement. Patients who undergo TT or SP with 8-hour postoperative PTH levels greater than or equal to 15 pg/mL (1.6 pmol/L) are at low risk for developing postoperative hypocalcemia, whereas those with PTH levels less than 15 pg/mL (1.6 pmol/L) have a high risk of developing hypocalcemia.

Measurement of parathyroid hormone and application of parathyroid hormone in intraoperative monitoring.

There has been a clear progression in assays for the analysis of PTH and its clinical applications. This includes the innovative use of PTH as a point-of-care assay as an intraoperative measure of the success of parathyroid surgery. The rapid PTH assay has served as a model for the development of other rapid hormone assays, such as for adrenocorticotropic hormone,although the clinical usefulness of these other applications is less well established. Knowledge of the circulating forms of PTH continues to progress. Information about the biologic and immunologic activities of these forms will aid in the interpretation and clinical use of current assays and in the development of new assays with improved specificities. The clinical laboratory will continue to play a vital role in providing testing and support for this important mediator of mineral metabolism.

Intraoperative parathyroid hormone testing: survey of testing program characteristics.

OBJECTIVE: To examine the number and testing characteristics of laboratories that offer intraoperative testing of intact parathyroid hormone (PTH). DESIGN: Laboratories (n = 355) that participated in 2001 in PTH proficiency testing with the College of American Pathologists Special Ligand Survey were surveyed about intraoperative PTH testing. RESULTS: Of the 320 laboratories that responded to the survey, 92 performed intraoperative PTH testing. Testing practices were divided nearly equally among laboratories that performed intraoperative PTH testing for all parathyroidectomies (40%), most but not all cases (31%), and less than half of cases (30%). Testing frequency usually was low, with about two thirds of laboratories reporting 5 or fewer cases per month. A surprising finding was that, although intraoperative PTH testing originally became widely practiced as a point-of-care test, 71% of laboratories performed testing in a central laboratory, 6% in satellite laboratories, and only 23% in operating suites. A survey of methods showed that 33% used the manual QuiCk-Intraoperative test, 47% used the automated Immulite Turbo intact PTH assay, and 20% used other methods. CONCLUSIONS: Intraoperative testing of intact PTH, although relatively new, has come into widespread practice during parathyroid surgery. Service delivery has evolved from a point-of-care model toward a central laboratory model, with this test serving as an illustrative example of factors that affect the balance between point-of-care and laboratory testing.

Parathyroid surgery: separating promise from reality.

We set out to determine the accuracy in predicting the success of biochemical and localizing studies for use in a minimally invasive parathyroidectomy. Preoperative sestamibi scans, intraoperative gamma-probe examinations, and intraoperative PTH (IOPTH) monitoring were performed on a prospective cohort of patients. Seventy-one patients were included in the study. Of the 59 patients (83%) with primary HPT, adenoma localization by sestamibi scanning was correct in 95% with solitary adenomas, but was correct in only 25% of the 14 patients with multiple adenomas. In patients with secondary and tertiary disease, sestamibi scanning incorrectly identified a single hot spot in 64% of cases. In no case of hyperplasia was the probe useful in locating other glands after a single gland was removed. IOPTH was accurate in 78% of patients with primary disease and in only 45% of patients with nonprimary disease. A minimal approach can be considered in a select group of patients that does not have familial primary HPT, secondary or tertiary disease, coexisting thyroid pathology, or an equivocal sestamibi scan. Only patients with a positive single hot spot on sestamibi scan can be considered candidates. Using this criteria only 64% of all patients with hyperparathyroidism are candidates for a minimally invasive approach. The combination of a solitary hot spot on sestamibi scan and a fall in IOPTH allows the surgeon to make the correct decision regarding the need to convert to a bilateral approach in 93% of these selected patients.