Results of surgical therapy of functioning pituitary adenomas.

INTRODUCTION: Functioning pituitary adenomas lead to substantial morbidity and increased mortality associated with typical endocrine syndromes. Surgical therapy is an integral part of the management of these tumours. The aim of this study was to evaluate the results of surgical transnasal procedures in patients with functioning pituitary adenomas who underwent the surgery at the Department of Neurosurgery, University Hospital Olomouc. METHODS: Patients with functioning pituitary adenoma (ACTH, GH, PRL) were indicated for surgery. All patients underwent preoperative and postoperative endocrinological examination and laboratory tests to assess excessive or deficient hormonal production and imaging examination. RESULTS: The cohort consisted of 58 patients, 33 of whom were women and 25 men. The age range was 12-77 years (mean age 47.6 years). Microadenoma was diagnosed in 58.6% of patients and macroadenoma in 41.4% of patients. The most common hypersecretory syndrome was excessive production of growth hormone (56.9%), followed by excessive production of adrenocorticotropic hormone (24.1%) and prolactin (12.1%). In the group with excessive production of ACTH, complete remission was achieved after the first surgery in 78.6% of cases (72.8% for microadenomas (8) and 100% (3) cases in macroadenomas); in the group with excessive GH production in 51.4% (63.2% (7) in microadenomas and 46.2% (12) cases in macroadenomas). In the group with excessive production of PRL, it was 57.1% (100% (2) in microadenomas and 40% (2) cases in macroadenomas). CONCLUSION: Surgical therapy in the presented cohort led to the normalisation of hormonal excessive production in 58.6% of cases. A combination of drug therapy and radiotherapeutic methods was necessary in the remaining cases to achieve hormonal remission.

Single-nuclei and bulk-tissue gene-expression analysis of pheochromocytoma and paraganglioma links disease subtypes with tumor microenvironment.

Pheochromocytomas (PC) and paragangliomas (PG) are rare neuroendocrine tumors associated with autonomic nerves. Here we use single-nuclei RNA-seq and bulk-tissue gene-expression data to characterize the cellular composition of PCPG and normal adrenal tissues, refine tumor gene-expression subtypes and make clinical and genotypic associations. We confirm seven PCPG gene-expression subtypes with significant genotype and clinical associations. Tumors with mutations in VHL, SDH-encoding genes (SDHx) or MAML3-fusions are characterized by hypoxia-inducible factor signaling and neoangiogenesis. PCPG have few infiltrating lymphocytes but abundant macrophages. While neoplastic cells transcriptionally resemble mature chromaffin cells, early chromaffin and neuroblast markers are also features of some PCPG subtypes. The gene-expression profile of metastatic SDHx-related PCPG indicates these tumors have elevated cellular proliferation and a lower number of non-neoplastic Schwann-cell-like cells, while GPR139 is a potential theranostic target. Our findings therefore clarify the diverse transcriptional programs and cellular composition of PCPG and identify biomarkers of potential clinical significance.

Hypertension outcomes of adrenalectomy for unilateral primary aldosteronism.

PURPOSE: To evaluate laboratory and clinical results after unilateral adrenalectomy in patients with primary aldosteronism (PHA). METHODS: A cross-sectional analysis was performed using data from patients who underwent transperitoneal laparoscopic adrenalectomy for PHA, between January 2008 and December 2019. Surgical indications were based on adrenal venous sampling without ACTH stimulation. Analyses included patient demographics; preoperative clinical, pharmacological, laboratory, and radiological data; and postoperative results assessed after a median of 4 months. Antihypertensive drug use was quantified by estimating the daily defined dose (DDD) of antihypertensive medication, thus enabling standardized comparison of dosage between the drug classes. Statistical assessments included univariable and multivariable logistic regression analysis. RESULTS: This study enrolled 87 patients. The patients were taking 5.4 DDD of antihypertensive medication before surgery, and 3.0 DDD after surgery. Complete biochemical success of surgery was reached 67 patients (77%), 19 patients (22%) had partial biochemical success. Complete clinical success with normalization of blood pressure and withdrawal of all antihypertensive drugs was achieved in 19 patients (22%). 57 patients (65%) exhibited a reduction of DDD after surgery and/or improvement of blood pressure-partial clinical success. Thus, in 76 (87%) of all enrolled patients, surgery had an overall positive effect on hypertension control. Multivariable logistic regression showed that complete clinical success was independently associated with female gender and baseline sum of antihypertensive drugs DDD < 4. CONCLUSION: A majority of patients undergoing unilateral adrenalectomy for PHA achieved markedly improved hypertension control, despite almost halving their antihypertensive medication. Almost a quarter of patients were cured and able to cease using all antihypertensive drugs.

Germline SUCLG2 Variants in Patients With Pheochromocytoma and Paraganglioma.

BACKGROUND: Pheochromocytoma and paraganglioma (PPGL) are neuroendocrine tumors with frequent mutations in genes linked to the tricarboxylic acid cycle. However, no pathogenic variant has been found to date in succinyl-CoA ligase (SUCL), an enzyme that provides substrate for succinate dehydrogenase (SDH; mitochondrial complex II [CII]), a known tumor suppressor in PPGL. METHODS: A cohort of 352 patients with apparently sporadic PPGL underwent genetic testing using a panel of 54 genes developed at the National Institutes of Health, including the SUCLG2 subunit of SUCL. Gene deletion, succinate levels, and protein levels were assessed in tumors where possible. To confirm the possible mechanism, we used a progenitor cell line, hPheo1, derived from a human pheochromocytoma, and ablated and re-expressed SUCLG2. RESULTS: We describe 8 germline variants in the guanosine triphosphate-binding domain of SUCLG2 in 15 patients (15 of 352, 4.3%) with apparently sporadic PPGL. Analysis of SUCLG2-mutated tumors and SUCLG2-deficient hPheo1 cells revealed absence of SUCLG2 protein, decrease in the level of the SDHB subunit of SDH, and faulty assembly of the complex II, resulting in aberrant respiration and elevated succinate accumulation. CONCLUSIONS: Our study suggests SUCLG2 as a novel candidate gene in the genetic landscape of PPGL. Large-scale sequencing may uncover additional cases harboring SUCLG2 variants and provide more detailed information about their prevalence and penetrance.

Deep Membrane Proteome Profiling Reveals Overexpression of Prostate-Specific Membrane Antigen (PSMA) in High-Risk Human Paraganglioma and Pheochromocytoma, Suggesting New Theranostic Opportunity.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells of adrenal medulla or sympathetic or parasympathetic paraganglia, respectively. To identify new therapeutic targets, we performed a detailed membrane-focused proteomic analysis of five human paraganglioma (PGL) samples. Using the Pitchfork strategy, which combines specific enrichments of glycopeptides, hydrophobic transmembrane segments, and non-glycosylated extra-membrane peptides, we identified over 1800 integral membrane proteins (IMPs). We found 45 "tumor enriched" proteins, i.e., proteins identified in all five PGLs but not found in control chromaffin tissue. Among them, 18 IMPs were predicted to be localized on the cell surface, a preferred drug targeting site, including prostate-specific membrane antigen (PSMA), a well-established target for nuclear imaging and therapy of advanced prostate cancer. Using specific antibodies, we verified PSMA expression in 22 well-characterized human PPGL samples. Compared to control chromaffin tissue, PSMA was markedly overexpressed in high-risk PPGLs belonging to the established Cluster 1, which is characterized by worse clinical outcomes, pseudohypoxia, multiplicity, recurrence, and metastasis, specifically including SDHB, VHL, and EPAS1 mutations. Using immunohistochemistry, we localized PSMA expression to tumor vasculature. Our study provides the first direct evidence of PSMA overexpression in PPGLs which could translate to therapeutic and diagnostic applications of anti-PSMA radio-conjugates in high-risk PPGLs.

Adipocytokines in Graves' orbitopathy and the effect of high-dose corticosteroids.

Graves' orbitopathy (GO) is a serious, progressive eye condition seen in patients with autoimmune thyroid disease. GO is characterized by inflammation and swelling of soft orbital tissues. Adipose tissue produces cytokine mediators called adipokines. The present study focuses on the relationship between serum levels of selected adipokines in patients with GO, comparing them with the control group, and uniquely describes the effect of high-dose systemic corticosteroids (HDSC) on their levels. For the purposes of this study, we collected blood samples before and after the treatment with HDSC from 60 GO patients and 34 control subjects and measured serum levels of adiponectin, AIF-1, A-FABP and FGF-21. Levels of adiponectin significantly differed among the three study groups (ANOVA p = 0.03). AIF-1 levels were also significantly different among the study groups (ANOVA p < 0.0001). AIF-1 was significantly associated with the presence of GO after adjusting for clinical factors (age, sex, smoking and BMI) and level of TSH (odds ratio 1.003, p < 0.01). This finding could enforce targeting macrophages in treatment strategies for GO since AIF-1 is considered as a marker of their activation.

Differential diagnosis of hypoglycemia.

Our review summarizes the possible differential diagnoses of hypoglycemia. It confirms the absolute necessity of fulfilling all the three Whipple hypoglycemia criteria. Briefly is mentioned Clinical symptoms of hypoglycemia are briefly mentioned and several ways to classify the hypoglycemic events are offered. Highlighted is the recommended approach to distinguish patients as seemingly ill and healthy and also as hypoglycemia occurring in diabetic and non-diabetic. All the classifications and recommendations are summarized in attached tables and schemes.

Safe and effective percutaneous ethanol injection therapy of 200 thyroid cysts.

INTRODUCTION: Ultrasound-guided percutaneous ethanol injection therapy (US-PEIT) is a minimally invasive procedure that may be performed as an alternative to surgery for the treatment of recurrent symptomatic thyroid cysts for which simple aspiration failed. The present study aimed at assessing US-PEIT in a large cohort of patients, identifying factors influencing treatment outcome. METHODS: Retrospective analysis of 193 patients with 200 thyroid cysts who underwent US-PEIT in 2004-2018. RESULTS: The initial median cyst volume was 8.5 mL [5.5-16.0]; median final volume at 12 months after the completion of therapy was 0.5 mL [0.2-1.3]. A Volume Reduction Rate (VRR) of 95.0% [86.7-98.0] was achieved. For successful US-PEIT, relatively small total amount of ethanol was needed, on average corresponding to 20.0% [16.7-28.6] of the initial cyst volume. VRR positively correlated with the initial cyst volume and negatively with the presence of complex cyst. Multiple regression analysis showed the presence of complex cyst as an independent predictor of treatment efficacy. CONCLUSION: US-PEIT of thyroid cysts of all sizes was very successful with using total amounts of ethanol, corresponding to ≈20% of the initial cyst volume.

Hypoglycemia as a Symptom of Neoplastic Disease, with a focus on Insulin-like Growth Factors Producing Tumors.

This article reviews the current knowledge of uncommon causes of hypoglycemia, with a focus on neoplastic disease. However, these situations are rare. They commonly accompany severely ill patients and therefore a proper diagnosis is the basis for relevant treatment. Here we discuss the pathophysiological foundation of hypoglycemia - situations caused by increased insulin production or sensitivity - but we also focus on different cytokines which could cause hypoglycemia, especially IGF-II production in what are called nonislet cell tumors. From the clinical perspective we can divide the patients who are affected into "seemingly ill" or "healthy patients" and lead the diagnostic process accordingly.

Characteristic CT features of pheochromocytomas - probability model calculation tool based on a multicentric study.

OBJECTIVES: The aim of the study was to evaluate the CT features of adrenal tumors in an effort to identify features specific to pheochromocytomas and second, to define a feasible probability calculation model. METHODS: This multicentric retrospective study included patients from the period 2003 to 2017 with an appropriate CT examination and a histological diagnosis of an adrenal adenoma, pheochromocytoma, adrenocortical carcinoma, or metastasis. In total, 346 patients were suitable for the CT image analysis, which included evaluation of the largest diameter, the shape of the lesion, the presence of central necrosis and its margins, and the presence of an enhancing peripheral rim ("ring sign"). RESULTS: Pheochromocytomas have a significantly more spherical shape (P<0.001), whereas an elliptical shape significantly reduces the probability of a pheochromocytoma (odds ratio = 0.015), as does another shape (odds ratio = 0.006). A "ring sign" is also more frequent in pheochromocytomas compared to other adrenal tumors (P=0.001, odds ratio = 6.49). A sharp necrosis also increases the probability of a pheochromocytoma more than unsharp necrosis (odds ratio 231.6 vs. 20.2). The probability calculation model created on the basis of the results confirms a high sensitivity and specificity (80% and 95%). CONCLUSION: This study confirms the value of anatomical features in the assessment of adrenal masses with the ability to significantly improve the identification of pheochromocytomas. Advanced assessment of the tumor shape was defined and a original comprehensive calculating tool of the pheochromocytoma probability was created on the basis of the results presented here and could be used in clinical routine.

An isolated Xp deletion is linked to autoimmune diseases in Turner syndrome.

Background Females with Turner syndrome (TS) are prone to develop autoimmune diseases (AIDs). The X chromosome contains several immune-related genes. Growth hormone (GH) and estrogens modulate the immune system. We aimed to clarify whether the loss of a specific X chromosome gene locus and the administration of GH and estradiol facilitate the development of AIDs in TS females. Methods Retrospective data on clinical course, AIDs, karyotype and treatment were analyzed from a cohort of 286 Czech females with TS (current age 2.8-43.3 years; median age 18.7 years). The karyotypes were sorted using two different classification systems: a mosaicism-focused and an isochromosome (isoXq)-focused approach. Karyotype subgroups with a significantly higher prevalence of AIDs were further evaluated. Data of common therapies were correlated with the prevalence of AIDs. Results The most frequent AIDs were autoimmune thyroid disease (AITD; 37.4%; n = 107) and celiac disease (CD; 8.7%; n = 25). All karyotype subgroups were prone to develop AIDs. Females with an isolated Xp deletion had a significantly higher prevalence of AITD and CD compared to all other individuals with TS (AITD: 66.0% vs. 31.5%, p < 0.0001; CD: 17.4% vs. 7.2%; p = 0.04, respectively). We observed no link between the mean age at initiation as well as the duration of GH and/or estrogen administration and the occurrence of AIDs. Conclusions Isolated Xp deletion contributes to the development of AIDs in TS patients. The haploinsufficiency of genes located in Xpter-p11.2 may explain this observation. Common therapies used in TS do not modify the risk of AIDs.

RETROSPECTIVE ANALYSIS OF PATIENTS WITH GRAVES ORBITOPATHY TREATED BY PULSES OF METHYLPREDNISOLONE, WITH A FOCUS ON ADVERSE EVENTS.

OBJECTIVE: Graves orbitopathy (GO) is an extrathyroidal manifestation of autoimmune thyroid disease. Early treatment with glucocorticoids in appropriately selected patients is recommended for active, moderate to severe, and sight-threatening disease. The recently published European Group on Graves Orbitopathy guidelines re-evaluated the recommended doses of intravenous methylprednisolone (ivMP) in response to the potential for adverse effects. We retrospectively reviewed our patient cohort treated with our ivMP protocol and analyzed the side effects of this treatment when given during hospitalization in our tertiary referral center. METHODS: Between May 2007 and May 2017, a total of 171 consecutive patients with active, moderate to severe, or sight-threatening GO were treated with ivMP in a cumulative dose of 7.5 grams, given monthly in three hospital sessions. Adverse events were reported using Version 4 of Common Terminology Criteria for Adverse Events. RESULTS: Ninety-two percent of patients who started the treatment were able to finish it; 5% did not finish the study due to adverse events, and 3% did not finish the treatment protocol because of noncompliance. The most common adverse events were asymptomatic changes in laboratory values (liver enzymes), psychiatric disorders, and infectious complications. None of the patients in the study died during the ivMP treatment, including those patients who experienced adverse effects or discontinued the protocol because of noncompliance. CONCLUSION: High-dose ivMP for active, moderate to severe, and sight-threatening GO, when applied cautiously in carefully selected and monitored patients, is generally safe during the treatment period. ABBREVIATIONS: AE = adverse effect; CAS = clinical activity score; CTCAE = Common Terminology Criteria for Adverse Events; DM = diabetes mellitus; EUGOGO = European Group on Graves Orbitopathy; GC = glucocorticoid; GO = Graves orbitopathy; ivMP = intravenous methylprednisolone.

Targeting NAD+/PARP DNA Repair Pathway as a Novel Therapeutic Approach to SDHB-Mutated Cluster I Pheochromocytoma and Paraganglioma.

Purpose: Cluster I pheochromocytomas and paragangliomas (PCPGs) tend to develop malignant transformation, tumor recurrence, and multiplicity. Transcriptomic profiling suggests that cluster I PCPGs and other related tumors exhibit distinctive changes in the tricarboxylic acid (TCA) cycle, the hypoxia signaling pathway, mitochondrial electron transport chain, and methylation status, suggesting that therapeutic regimen might be optimized by targeting these signature molecular pathways.Experimental Design: In the present study, we investigated the molecular signatures in clinical specimens from cluster I PCPGs in comparison with cluster II PCPGs that are related to kinase signaling and often present as benign tumors.Results: We found that cluster I PCPGs develop a dependency to mitochondrial complex I, evidenced by the upregulation of complex I components and enhanced NADH dehydrogenation. Alteration in mitochondrial function resulted in strengthened NAD+ metabolism, here considered as a key mechanism of chemoresistance, particularly, of succinate dehydrogenase subunit B (SDHB)-mutated cluster I PCPGs via the PARP1/BER DNA repair pathway. Combining a PARP inhibitor with temozolomide, a conventional chemotherapeutic agent, not only improved cytotoxicity but also reduced metastatic lesions, with prolonged overall survival of mice with SDHB knockdown PCPG allograft.Conclusions: In summary, our findings provide novel insights into an effective strategy for targeting cluster I PCPGs, especially those with SDHB mutations. Clin Cancer Res; 24(14); 3423-32. ©2018 AACR.

Clinical and immunological changes in patients with active moderate-to-severe Graves' orbitopathy treated with very low-dose rituximab.

INTRODUCTION: Glucocorticoids represent the therapy of choice for active and moderate-to-severe Graves' orbitopathy (GO). In some patients, rituximab, a monoclonal antibody against the cluster of differentiation (CD) 20 receptor of B-lymphocytes, can serve as a second-line or an alternative treatment. The effect of very low-dose of rituximab on the clinical activity of GO and corresponding clinical or laboratory changes is reported. MATERIAL AND METHODS: Changes of Clinical Activity Score (CAS) for GO, proptosis, levels of thyroid-stimulating hormone receptor antibodies, and depletion of CD19+ and CD20+ B-lymphocytes were determined in ten patients (two men and eight women) with active moderate-to-severe GO treated with a single 100-mg dose of rituximab. Correlations between differences of clinical and laboratory parameters were performed. RESULTS: A significant decrease of CAS was found during subsequent examinations compared to the baseline values. A significant depletion of CD19+ and CD20+ B-lymphocytes was detected after rituximab administration. Differences between follow-up and baseline levels of CD20+ positively correlated with differences in CAS after six (p < 0.05) and 12 months (p < 0.01). Differences in CD19+ levels correlated with differences in CAS after 12 months (p < 0.05) of the treatment. Two patients developed dysthyroid optic neuropathy (DON) requiring orbital decompression. No other rituximab side effects were reported during the whole study duration. CONCLUSIONS: A single very low-dose of rituximab appears to be very well tolerated and effective enough to reduce clinical activity in active moderate-to-severe GO patients without impending DON.

[Symptomatic and asymptomatic primary hyperparathyroidism in outpatient care - current issues]. / Péce o nemocné se symptomatickou a asymptomatickou primární hyperparatyreózou v ambulantní praxi dnes.

OBJECTIVE: To assess the diagnostic and therapeutic options in the care of patients with primary hyperparathyreosis in outpatient practice.Cohort and methods: The study included all the patients with primary hyperparathyroidism treated at the 2nd Internal Medicine Department, Masaryk University and the University Hospital of St. Anne in Brno in the period from Jan 1, 2008 to Dec 31, 2013. The sample consisted of 218 patients, including 41 men and 177 women. Patients with secondary hyperparathyroidism, especially patients with underlying hypovitaminosis D, renal insufficiency and those taking medications with possible effects on parathyroid hormone levels, have not been included in the study. A special attention was paid to differences between the normocalcaemic and hypercalcaemic patients. Ultrasound scanning was performed in all patients, while scintigraphy was indicated in patients who are considered for possible surgical treatment. RESULTS: In the group of 218 patients, serum calcium levels at the baseline were pathologically elevated in 31 patients (14 %) and normal in 187 patients (86 %). One fifth of patients with normocalcaemic primary hyperparathyroidism developed long-term hypercalcaemia - within two years in two thirds of the patients from the onset of the disease and sporadically also after more than four years of follow-up. Parathyroid adenoma was found and removed in 30 hypercalcemic patients (in 97 % of all 31 hypercalcemic patients operated on) and in 2 normocalcemic patients (40 % of all 5 the normocalcemic patients operated on). Pharmacological treatment was administered to 22 patients, of which 9 patients received long-term treatment and 13 patients received pharmacotherapy only during the preoperative preparation for patients with very high serum calcium levels. CONCLUSION: The results support the opinion that primary hyperparathyroidism is a biphasic disease. The initial normocalcemic period is often asymptomatic or associated with symptoms of little importance. Severe complications, however, may already be present also in normocalcemic patients. The decision of when patients with normocalcemic primary hyperparathyroidism should be monitored and when initiation of treatment is needed should also require more detailed information.Key words: hypercalcaemia - hyperparathyroidism asymptomatic and primary - normocalcaemia - outpatient care - parathyroid hormone - surgery and pharmacotherapy.

[Endocrine orbitopathy - the topic still alive]. / Endokrinní orbitopatie - téma stále zivé.

Endocrine orbitopathy (EO) must be understood mainly as a result of oxidative stress. The pathological process finally affects both the appearance and vision of the patient. In the case of inappropriate or late treatment or lack of patient cooperation, it significantly influences the quality of life of those affected. In spite of the sophisticated dia-gnostic algorithms, in some cases it is difficult to confirm the diagnosis of EO. The range of laboratory methods, the essential part of the diagnostic process, has only recently been extended by the possibility of quantification of specific, stimulating immunoglobulins (TSI). A major shortcoming may be seen in an undervalued importance of orbital ultrasonography, in particular of the eye muscles (US).Key words: biological treatment - endocrine orbitopathy (EO) - Graves-Basedow disease (GB) - "hashitoxicosis" (HTX) - hyaluronan synthase 2 (HAS2) - thyroid-blocking immunoglobulins (TBI) - thyroid-stimulating immunoglobulins (TSI) - hyaluronic acid (HA) - lymphocytary, Hashimotos thyroiditis (HT) - pulse therapy - TSH-receptor - transcription factors FOXOs - orbital ultrasonography, mainly of the eye muscles (US).

[Hypoglycemia as a symptom of cancer in adults]. / Hypoglykemie jako symptom maligního onemocnení v dospelém veku.

UNLABELLED: Decrease of blood glucose levels below 3 mmol/l is in fully developed cases accompanied by neuroglycopenic symptoms that may even lead to altered state of consciousness. The treating physician frequently faces a complicated situation. This may be due to inappropriately administered drugs including cases motivated by self-harm intentions (insulin, insulin secretagogues), or alcohol abuse. Undernourished people, or those afflicted with a serious systemic infection, end-stage liver or kidney diseases or with a failing heart, belong to a risk group. Hypoglycemia typically accompanies hypocorticism (Addisons disease) or lack of glucagon. Endogenous hyperinsulinism caused by a hormonally active pancreatic cancer, that is, by a neuroendocrine tumour - insulinoma, is a possibility to be considered. A hidden cause of hypoglycemias may be a pancreatic-beta- cell dysfunction (nesidioblastosis, or non-insulin pancreatogenous hypoglycemia). A similar situation may arise following gastric bypass surgery. Hypoglycemia incited by the presence of antibodies to insulin or its receptor is cited in literature as a very rare problem. One section in the differentially diagnostic thinking is dedicated to hypoglycemic states accompanying neoplastic, malign processes. Insulin is demonstrably not a responsible agent here, it is a polypeptide structurally close to it, a somatomedin abbreviated as IGF2. KEY WORDS: endoscopic ultrasound pancreatography (EUPG) - hypoglycemia mediated by tumour cells other than ß cells (NIPHS) - insulin-like growth factor (IGF1, IGF2) - pro-insulin-like growth factor IGF2 (pro-IGF2).

PRIMARY HYPERPARATHYROIDISM, WITH A FOCUS ON MANAGEMENT OF THE NORMOCALCEMIC FORM: TO TREAT OR NOT TO TREAT?

OBJECTIVE: The aim of this study was to determine reasonable care for normocalcemic primary hyperparathyroidism (NCPHPT) patients treated at the endocrine clinic. METHODS: The study is based on 218 outpatient cases of primary hyperparathyroidism (PHPT), 187 (86%) of whom were NCPHPT. Subjective complaints, biochemical tests, imaging, and treatment outcome for NCPHPT patients were monitored and compared with the same parameters in patients with hypercalcemic hyperparathyroidism. The number of patients with newly diagnosed NCPHPT who became hypercalcemic and the time period in which it happened were also recorded. RESULTS: Over 6 years of study, in total, 36 of 187 originally normocalcemic patients became hypercalcemic (19%); 24 of 36 within 2 years and 2 of 36 later than after 4 years. Sestamibi scintigraphy was performed in 103 normocalcemic patients (adenoma was detected in 5 cases) and in 46 hypercalcemic patients with pathologically elevated serum calcium levels at the time of assessment (adenoma was detected in 32 of 46 cases). Surgery was performed in 33 patients, 11 of whom were originally normocalcemic (i.e., 6% of all 187 originally normocalcemic patients), and 22 were hypercalcemic from the outset (i.e., 71% of all 31 originally hypercalcemic patients). CONCLUSION: Some NCPHPT patients converted to hypercalcemic, mostly within 2 years, but some after 4 years or later. Normocalcemic patients should be monitored on a long-term basis, as it is impossible to anticipate when and which normocalcemic patients will become hypercalcemic. Imaging is much less effective in normocalcemic than in hypercalcemic patients.