Clinical characteristics and surgical outcomes of vertebral lesions associated with tumor-induced osteomalacia: report of 16 patients and review of the literature.

Vertebral tumors in patients with tumor-induced osteomalacia (TIO) have a low diagnostic rate and poor postoperative outcomes. The application of 68 Ga-DOTATATE-PET/CT significantly increased the detection rate. Compared with tumor curettage, segmental resection was recommended as the preferred surgical type due to its high recovery rate. PURPOSE: Tumor-induced osteomalacia (TIO) is an acquired hypophosphatemic osteomalacia, and surgery is the first-line therapy. Most TIO tumors are found in the bones of the appendicular skeleton, cranium, and paranasal sinuses but rarely in the vertebrae. Tumor curettage and segmental resection are the two main surgical options for vertebral TIO patients. However, research on the clinical characteristics and surgical prognosis of vertebral TIO patients is rare. In the present study, for the first time, we investigated the clinical characteristics of 16 vertebral TIO patients and compared the surgical outcomes of patients who underwent surgery via two different surgical methods. METHODS: This was a retrospective cohort study. In this study, we included 16 adult TIO patients with lesions in vertebrae from Peking Union Medical College Hospital (PUMCH), all of whom underwent surgery. Baseline laboratory data were collected through medical records review. Technetium-99 m octreotide scintigraphy (99Tcm-OCT) and 68gallium-DOTA-TATE-positron emission tomography/computed tomography (68 Ga-DOTATATE-PET/CT) were conducted at the Department of Nuclear Medicine of PUMCH. The tumor histopathology was confirmed by a senior pathologist at our center. RESULTS: Vertebral TIO patients had lower serum phosphorus and TmP/GFR and higher serum alkaline phosphatase (ALP), serum parathyroid hormone (PTH), and serum C-terminal cross-linked telopeptide of type I collagen (ß-CTX) levels than the normal range. The sensitivity of 68 Ga‒DOTATATE PET/CT was 100%, significantly greater than that of 99Tcm-OCT (40%). After comparing the outcomes between the two surgical methods, we found that the recovery rate after segmental resection (62.5%) was greater than that after tumor curettage (12.5%). In the thoracic and sacral vertebrae, segmental resection surgery had a good prognosis. CONCLUSION: 68 Ga-DOTATATE PET/CT could serve as the first diagnostic tool in patients with vertebral TIO, and segmental resection could be used as the preferred surgery. This study would raise awareness of the clinical features and management of these rare vertebral TIO patients.

Influence of Obesity and Changes in Weight or BMI on Incident Fractures in Postmenopausal Women: From Peking Vertebral Fracture Study.

This study aims to investigate the influence of overweight/obesity and change in weight or body mass index (BMI) on incident fractures among Chinese postmenopausal women. According to BMI, 754 postmenopausal women were categorized into normal weight (NW), overweight (OW), and obesity (OB) groups, respectively. We used data from the baseline and the second survey for statistical analysis, including anthropometric data, clinical fractures, and morphometric vertebral fractures (MVFs) assessed by X-rays. The prevalence of previous MVFs was 32.7% and 21.8% in the OB and NW groups, respectively (p < 0.05). All incident fractures and incident MVFs accounted for 10.7 and 6.3% among all participants within five years. Overweight/obesity and increase in weight or BMI during the follow-up had no associations with all incident fractures, incident MVFs, and incident clinical non-VFs among all participants. However, after multivariate adjustment, the increased BMI at baseline was the risk factor of incident MVFs in the OW group (odds ratio, OR 2.06, 95% confidence interval, 95% CI 1.16-3.66, p = 0.014), and increase in weight (OR 0.89, 95% CI 0.79-0.99, p = 0.036) or BMI (OR 0.77, 95% CI 0.59-0.99, p = 0.045) during the follow-up were the protective factors of all incident fractures in the NW group. Overweight/obesity and change in weight or BMI do not correlate with fracture risk in postmenopausal women, but an increase in weight is the protective factor against incident fractures in normal-weight participants. Overweight postmenopausal women with a higher BMI should pay attention to the risk of MVFs.

Na-Cl Co-transporter (NCC) gene inactivation is associated with improved bone microstructure.

Gitelman syndrome (GS) is the disease model of the inactivation of thiazide-sensitive sodium chloride cotransporter (NCC), which is believed to benefit bone mass and reduce fracture risk. In this study, we found that GS patients have superior bone microarchitecture, which is associated with the disease status. Several decreased bone parameters with aging in healthy controls were reversed in GS patients to a certain extent. PURPOSE: To evaluate the impact of the inactivation of NCC on bone turnover and microarchitecture in Gitelman syndrome patients. METHODS: A cross-sectional study was conducted in 45 GS patients (25 males and 20 females). Serum procollagen type 1 N-terminal propeptide (P1NP), ß-carboxy-terminal crosslinked telopeptide of type 1 collagen (ß-CTX), and osteocalcin were measured. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in GS patients and age- and sex-matched healthy controls. Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously. RESULTS: GS patients had a relatively lower level of ß-CTX. aBMD at several skeletal sites was improved in GS patients. HR-pQCT assessment revealed that GS patients had slightly thinner but significantly more compact trabecular bone (increased trabecular number and decreased thickness), notably decreased cortical porosity, and increased volume BMD (vBMD) at both the radius and tibia compared with controls. The disease severity, represented as the relationship with the minimum level of magnesium during the course and standard base excess, was associated with bone microarchitecture parameters after adjusting for age, sex, and BMI. The decreased vBMD and Tb.BV/TV, and increased Tb.Sp and Ct.Po with aging, were reversed in GS patients to a certain extent. CONCLUSION: GS patients have superior bone microarchitecture, which suggests that the inactivation of NCC might be beneficial for avoiding osteoporosis.

Diagnosis, treatment and genetic analysis of two cases of congenital hyperinsulinemic hypoglycemia caused by GCK gene mutation.

Congenital hyperinsulinemia (CHI) is a heterogeneous disorder characterized by persistent hypoglycemia due to inappropriate insulin secretion. A total of 15 gene mutations have already been reported to be associated with CHI. Among them, CHI caused by the GCK mutation is named GCK-CHI, which is considered to be a rare form of CHI. Here, we reported two cases of GCK-CHI diagnosed by genetic testing and summarized the clinical characteristics. In patients with recurrent or persistent hypoglycemia, CHI should be taken into consideration. Genetic testing should be perfomed in these patients to avoid misdiagnosis and provide accurate intervention, thus to improve prognosis.

Recurrent Femoral Fractures in a Boy with an Atypical Progeroid Syndrome: A Case Report.

Mutations in the gene LMNA cause a wide spectrum of diseases that are now referred to laminopathies, such as muscular dystrophies, cardiomyopathies, and progeroid syndromes. Atypical progeroid syndrome (APS) is a type of progeroid syndrome mainly associated with LMNA mutations. Abnormal skeletal features associated with APS, such as osteoporosis and acroosteolysis, are rarely reported, and recurrent fractures have never been documented. We present a 16-year-old Chinese male patient with the typical features of APS, such as progeroid manifestations, cutaneous mottled hyperpigmentation, generalized lipodystrophy, and severe metabolic complications. The patient has also been detected with some rare and severe skeletal features, such as severe osteoporosis, generalized thinning of cortical bone, and recurrent femoral fractures. Genetic mutation detection in the LMNA gene revealed a de novo heterozygous mutation, the c. 29C>T (p. T10I).

Incident Fracture Risk in Type 2 Diabetic Postmenopausal Women in Mainland China: Peking Vertebral Fracture Study.

Using data from the Peking Vertebral Fracture Study, we conducted a longitudinal cohort study to investigate the association between type 2 diabetes mellitus (T2DM) and the risk of incident fractures, especially of vertebral fractures (VFs), and we also examined the modifying effect of body mass index (BMI) on this association and the effect of bone mineral density (BMD) T-score as a risk factor for incident fractures in T2DM. Chinese postmenopausal women were enrolled (n = 982), among whom 186 had T2DM. Incident VFs were confirmed by lateral radiographs of the thoracolumbar spine (T4-L5), while incident clinical non-VFs were self-reported. BMDs at the lumbar spine (LS) and femoral neck (FN) were measured by dual-energy X-ray absorptiometry. T2DM and non-DM women were at similar risk for VFs (OR 0.74, 95% CI 0.32-1.74), even adjusting for age, BMI, BMD, and previous fractures. Meanwhile, T2DM women had nearly twice the risk for non-VFs (HR 1.95, 95% CI 1.11-3.35) compared with non-DM women. After stratifying by BMI, the risk of VFs remained similar between diabetics and non-diabetics despite their BMI status (p for interaction = 0.470), and the risk of non-VFs was positively associated with T2DM only in women with BMI ≥ 25 kg/m2 (HR 3.59, 95% CI 1.68-7.65) (p for interaction = 0.065). Although LS BMD T-score was similarly and negatively associated with incident VFs both in T2DM (OR 0.34, 95% CI 0.12-0.88) and non-DM women (OR 0.60, 95% CI 0.44-0.82) (p for interaction = 0.430), the FN BMD T-score was not found to be significantly associated with either non-VFs or VFs among T2DM women. Comparing T2DM and non-DM women with similar fracture risks, the mean difference in LS T-score was - 0.36 (95% CI - 1.77 to 1.04) for VF, and difference in FN T-score was 1.61 (95% CI - 0.11 to 3.34) for non-VF. In conclusion, Chinese postmenopausal women with T2DM had a similar risk of incident VFs, but a significantly higher risk of incident non-VF, compared to women without DM. Higher BMI did not modify the effect of T2DM on risk of VFs, but it increased the association between T2DM and risk of non-VFs. LS BMD T-score was similarly and negatively associated with VF risk in T2DM and non-DM women and appear to be useful for clinical evaluation of VF risk.

Calciotropic Hormones and the Prevalence of Vertebral Fractures in Chinese Postmenopausal Women with Vitamin D Insufficiency: Peking Vertebral Fracture Study.

This case-control study aimed to examine the effect of high serum parathyroid hormone (PTH) level, especially the effect of secondary hyperparathyroidism (SHPT) related to hypovitaminosis D, on bone metabolism and bone phenotypes. We included a total of 830 Chinese postmenopausal women aged ≥ 50 years with serum 25-hydroxyvitamin D (25(OH)D) level < 30 ng/ml, among whom 415 women had prevalent vertebral fractures (VFs) and others were age-matched controls. We measured serum levels of 25(OH)D, PTH and bone turnover markers (BTMs), which included C-terminal telopeptide of type I collagen (ß-CTX), N-aminoterminal prepeptide of type I procollagen (P1NP) and osteocalcin (OC). Bone mineral densities (BMDs) at lumbar spine and femoral neck were quantified by dual-energy X-ray absorptiometry. Morphometric VFs were validated by lateral radiograph of thoracolumbar spine. Compared to fracture-free controls, women with VFs exhibited a higher serum level of PTH and a higher percentage of SHPT (both p < 0.05), but had a similar serum level of 25(OH)D (p = 0.166). Positive correlations were depicted between PTH and BTMs (all p < 0.01), and between 25(OH)D and bone formation markers (p = 0.013 for OC, p = 0.068 for P1NP), whereas no significant correlation was identified between both calciotropic hormones and BMDs or between 25(OH)D and ß-CTX (all p > 0.05). Increasing PTH was associated with an increased risk of VFs independent of 25(OH)D and BMD [odds ratio (OR) per SD increase in PTH 1.016, 95% confidence interval (95% CI) 1.006-1.027]. Moreover, women with SHPT (i.e., > 68 pg/ml) had about three times odds for VF compared to women with normal PTH levels (OR 3.270, 95% CI 1.581-6.760). These data suggest that evaluated serum PTH level might promote the bone remodeling and then lead to increased risks of VFs among Chinese postmenopausal women with vitamin D insufficiency.

A Common Mutation and a Novel Mutation in the HPGD Gene in Nine Patients with Primary Hypertrophic Osteoarthropathy.

Primary hypertrophic osteoarthropathy (PHO) is a hereditary bone disease characterized by digital clubbing, periostosis, and pachydermia. The HPGD gene encoding 15-prostaglandin dehydrogenase and SLCO2A1 encoding one type of prostaglandin transporter were found to be responsible for PHO. Mutations of either gene would lead to increased level of prostaglandin E2 (PGE2), which might contribute to the constellation of the symptoms. The aim of the study was to analyze the HPGD gene and the clinical characteristics in nine patients with the diagnosis of PHO. Nine patients, (eight males and one female) including two siblings and seven sporadic cases, were enrolled in the study. Clinical features were summarized, and blood and urine samples were collected. Sanger method was used to sequence the HPGD gene to detect mutations. Urinary PGE2 and prostaglandin metabolite (PGE-M) levels for each patient were measured and compared to the healthy controls. A recurrent c.310_311delCT mutation was identified in all patients, of which six were homozygous, two were heterozygous, and one was compound heterozygous with this mutation and a novel heterozygous missense mutation c.488G>A (p.R163H). The levels of PGE2 in urine were much higher than normal in all patients, along with lower PGE-M levels. In conclusion, nine PHO patients were characterized by typical clinical manifestations including digital clubbing, periostosis, and pachydermia. A common mutation and a novel mutation in HPGD gene were identified to be responsible for the disease, and c.310_311delCT mutation is likely to be a hot-spot mutation site for Asian PHO patients.

Relationships between sclerostin and morphometric vertebral fractures, bone mineral density, and bone microarchitecture in postmenopausal women.

Higher sclerostin levels in postmenopausal women are associated with improved bone microarchitecture, areal and volumetric bone mineral density, and bone strength. However, the serum sclerostin level had no independent associations with the prevalence of morphometric vertebral fractures in this population after multivariable adjustment. PURPOSE: We aim to investigate the associations between serum sclerostin levels and morphometric vertebral fractures (VFs) prevalence, bone mineral density (BMD), and bone microarchitecture in postmenopausal women. METHODS: A total of 274 community-dwelling postmenopausal women were randomized enrolled. We collected general information and measured the serum sclerostin level. Morphometric VFs were assessed on the lateral thoracic and lumbar spine X-rays. Areal BMD and calculated trabecular bone score (TBS) were detected by dual-energy X-ray absorptiometry, and volumetric BMD and bone microarchitecture data were acquired from high-resolution peripheral quantitative computed tomography. RESULTS: The prevalence of morphometric VFs was 18.6% in the cohort, and it was significantly higher in the lowest quartile of the sclerostin group than that in the highest quartile of the sclerostin group (27.9% vs. 11.8%, p<0.05). But the serum sclerostin had no independent association with the prevalence of morphometric VFs after adjusting by age, body mass index, BMD at the lumbar vertebrae 1-4, and fragility fracture history after 50 years old (odds ratio: 0.995, 95% confidence interval: 0.987-1.003, p=0.239). The serum sclerostin level positively correlated with the areal, volumetric BMDs, and TBS. It also had significant positive associations with Tb.BV/TV, Tb.N, Tb.Th, and Ct.Th, and negative associations with Tb.Sp and Tb.1/N.SD. CONCLUSION: Chinese postmenopausal women with higher serum sclerostin levels had a lower prevalence of morphometric VFs, higher BMDs, and better bone microarchitecture. Nevertheless, the serum sclerostin level had no independent association with the prevalence of morphometric VFs.

The First Compound Heterozygous Mutations of DMP1 Causing Rare Autosomal Recessive Hypophosphatemic Rickets Type 1.

CONTEXT: Hereditary hypophosphatemic rickets (HR) consists of a group of inherited hypophosphatemia due to mutations of different genes, which need genetic analysis to make a differential diagnosis. Among them, autosomal recessive hypophosphatemic rickets type 1 (ARHR1), caused by a homozygous mutation of dentin matrix protein 1 (DMP1), is extremely rare, with only 30 reported patients. To date, there has been no case with compound heterozygous DMP1 mutations. OBJECTIVE: To report the first compound heterozygous mutations of DMP1 causing ARHR1 and confirm the effect of the mutation on DMP1 protein. METHODS: We report the clinical features of a Chinese patient with HR. Whole-exome sequencing (WES) was performed on the proband. Then, Cytoscan HD array, Sanger sequencing, and genomic quantitative PCR (qPCR) were used to confirm the mutations. A cell experiment was conducted to explore the effect of the mutation. RESULTS: The proband is a 4-year-old boy, who developed genu varum when he was able to walk at age 1 year and tooth loss after a mild hit at age 3.5 years. Physical examination, biochemical measurement, and imaging finding indicated HR. Family history was negative. WES performed on the proband revealed a novel start codon mutation (c.1A > T, p.Met1Leu) in DMP1 and a large deletion involving most of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family gene, including DSPP, DMP1, IBSP, and MEPE. The novel paternally inherited start codon mutation, which resulted in decreased expression of DMP1 protein with smaller molecular weight and cleavage defect, was confirmed by Sanger sequencing. The maternally inherited deletion was validated by Cytoscan and qPCR, and the breakpoint was finally identified by long-range PCR and Sanger sequencing. Manifestation of dentin dysplasia (DD) or dentinogenesis imperfecta (DGI) caused by DSPP mutations was absent in the patient and his mother, confirming that haploinsufficiency could not lead to DD or DGI. CONCLUSION: We report for the first time compound heterozygous DMP1 mutations consisting of a large deletion and a novel start codon mutation (c.1A > T, p.Met1Leu) in a Chinese patient with ARHR1.

Serum Irisin level is associated with fall risk, muscle strength, and cortical porosity in postmenopausal women.

Background: Irisin plays a role in bone-muscle crosstalk, but the relationship between the serum irisin level and bone microarchitecture remains unknown. Objective: This study aimed to investigate the relationships between serum irisin level and fall risk, muscle strength, bone mineral density (BMD), and bone microarchitecture among Chinese postmenopausal women. Methods: In all 138 postmenopausal women, handgrip strength, short physical performance battery (SPPB), and the timed up-and-go test were performed to evaluate muscle strength, physical performance, and fall risk, respectively. The serum irisin was measured. High-resolution peripheral quantitative computed tomography (HR-pQCT) was performed to acquire volumetric BMD and bone microarchitecture. Bivariate analysis was used to explore relationships between serum irisin level and muscle strength and HR-pQCT parameters. Univariate and multivariate linear regression analyses were performed to determine associations between serum irisin level and vBMD and cortical porosity (Ct.Po). Results: All participants had a median serum irisin level of 3.91 µg/ml. Participants with high fall risk had significantly lower serum irisin levels than those with low fall risk (2.22 µg/ml vs. 4.16 µg/ml, p=0.024). Irisin level was positively related to handgrip strength (rs=0.185, p=0.030) and SPPB performance. In univariate linear regression, serum irisin level was positively associated with cortical volumetric BMD (Ct.vBMD, radius: standardized ß=0.184, p=0.031; tibia: standardized ß=0.242, p=0.004), but it had no significant associations with Ct.vBMD after multivariate adjustment. After adjusting by age, height, serum sclerostin level, and body fat ratio, only Ct.Po at the distal radius had a significantly negative association with serum irisin level (standardized ß=-0.276, p=0.003). Conclusion: Postmenopausal women with lower serum irisin levels have a higher fall risk, weaker muscle strength, and higher cortical porosity. Moreover, serum irisin level has a positive association with Ct.vBMD, but it is affected by factors such as age.

Ultra-High Performance Liquid Chromatography-Mass Spectrometry-based Serum Metabolomics for Early Diagnosis of Refractory Tumor-induced Osteomalacia: A Case-control Study.

CONTEXT: Nearly 20% patients with tumor-induced osteomalacia (TIO) experienced recurrence or nonrecovery after surgery. Serum fibroblast growth factor 23 and phosphate concentrations are not sufficient for prognosis in such cases. Despite its importance for understanding of prognosis and underlying pathogenesis, the alteration of systemic metabolism in refractory TIO remains unclear. OBJECTIVE: We aimed to find the metabolomic characteristics of refractory TIO and establish a novel predictive model for early discriminating refractory TIO based on their serum metabolomics. DESIGN AND SETTING: Cross-section study for comparison of metabolomic profile between TIO and normal control and longitudinal study for identifying prognostic model. METHODS: Based on liquid chromatography-tandem mass spectrometry, we analyzed the global metabolomes of preoperative sera from 86 samples (32 TIO recovery patients, 11 nonremission patients, and 43 matched controls). Statistical analyses, pathway enrichment, and receiver operating characteristic analysis were performed to identified and evaluate potential markers. RESULTS: Sparse partial least squares discriminant analysis indicated a clear separation of metabolomic profiles between healthy controls (HC) and TIO patients. The serum metabolites altered in different prognostic groups. L-pipecolic acid, 2-dodecylbenzenesulfonic acid, and 2-deoxygalactopyranose were the top 3 metabolites that were significantly perturbed. A combination of L-pipecolic acid and 2-dodecylbenzenesulfonic acid demonstrated a high-performance panel for TIO prognosis evaluated by random forest algorithm (area under the curve = 0.921, 95% CI, 0.787-0.995). CONCLUSIONS: We investigate the global metabolomes of refractory TIO and identify potential prognostic biomarkers preliminarily. A high sensitivity and specificity panel were identified as promising discriminating predictors, which need to be verified in more patients. This work may demonstrate novel insights into TIO prognosis and pathogenesis.

Incident vertebral fracture and longitudinal BMD change in Chinese postmenopausal women with early CKD: Peking Vertebral Fracture Study.

Early chronic kidney disease (CKD) and non-CKD individuals had similar morphometric vertebral fracture (mVF) incidence and longitudinal bone mineral density (BMD) change. CKD did not modify the association between BMD and incident mVF status. Patients with a higher baseline BMD had a higher longitudinal BMD loss in early CKD. PURPOSE: The aim of this 5-year longitudinal cohort study was to compare the risk of incident morphometric vertebral fracture (mVF) and longitudinal bone mineral density (BMD) change between individuals with early chronic kidney disease (CKD) and those without CKD. METHODS: A total of 869 Chinese postmenopausal women were enrolled in the study. Serum creatinine levels were assessed using standard methods, and estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Incident mVF was confirmed through lateral radiographs of the thoracolumbar spine. BMDs at the lumbar spine (LS) and femoral neck (FN) were measured using dual-energy X-ray absorptiometry. CKD was defined based on eGFR values: 60-89 mL/min/1.73m2 for stage 2 (n = 511) and 30-59 mL/min/1.73m2 for stage 3 (n = 92). The non-CKD group included individuals with an eGFR greater than or equal to 90 mL/min/1.73m2. RESULTS: The incidence of mVF was not statistically different between individuals with early CKD and those without CKD (4.1% in non-CKD, 6.3% in CKD stage 2, and 7.6% in CKD stage 3; p = 0.348). Neither eGFR nor CKD status was significantly associated with incident mVF in the multivariate logistic regression analysis. Baseline BMD T-scores were negatively associated with incident mVF (LS T-score, OR = 0.603, 95% CI = 0.468-0.777; FN T-score, OR = 0.511, 95% CI = 0.350-0.746). No evidence of interaction between BMD T-scores and CKD status were identified (p = 0.284-0.785) . The differences in longitudinal BMD changes between non-CKD and CKD groups were comparable (FN BMD: -6.31 ± 7.20% in non-CKD, -5.07 ± 8.20% in CKD stage 2, and -4.49 ± 8.40% in CKD stage 3, p = 0.556; LS BMD: -1.38 ± 8.18% in non-CKD, -0.32 ± 7.14% in CKD stage 2, and 1.5 ± 6.97% in CKD stage 3, p = 0.406). Individuals with a higher baseline FN BMD showed a greater longitudinal FN BMD loss (r = -0.185, p < 0.001) . CONCLUSIONS: Our study revealed that early CKD was not associated with an increased risk of incident mVF or greater longitudinal BMD loss. Moreover, CKD did not modify the association between BMD and the risk of incident mVF, suggesting that the management and prevention of fractures in early CKD should be approached similarly to those without CKD. Measurement of BMD appears to be crucial for predicting incident mVF risk and longitudinal bone loss in early CKD.

Shift in Calcium From Peripheral Bone to Axial Bone After Tumor Resection in Patients With Tumor-Induced Osteomalacia.

CONTEXT: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by excessive production of fibroblast growth factor 23 (FGF23) by a tumor. After successful tumor resection, patients can recover from hypophosphatemia quicky. However, data on the changes in bone mineral density (BMD) and microstructure in the short term after surgery remained unclear. OBJECTIVE: This work aimed to investigate the postoperative changes in BMD and microstructure both in peripheral and axial bone in TIO patients. METHODS: We evaluated BMD and microarchitecture in 22 TIO patients using high-resolution peripheral quantitative computed tomography (HR-pQCT) and dual-energy x-ray absorptiometry (DXA) before and 3 months after surgery in this retrospective study. RESULTS: In this study, a total of 22 TIO patients who had recovered serum phosphate levels postoperatively were enrolled. After surgery, areal BMD (aBMD) increased by 21.6% in the femoral neck, by 18.9% in the total hip, and by 29.5% in the lumbar spine. Moreover, TBS increased by 14.1% (all P < .001). In contrast, trabecular or cortical volumetric BMD (vBMD), and microstructure of trabecular bone (trabecular number, separation and bone volume ratio) and cortical bone (cortical thickness and porosity) at the distal radius or tibia were further deteriorated. Correlation analyses found that changes in femoral neck and total hip aBMD were both conversely associated with changes in trabecular vBMD and bone volume ratio, while positively correlated with change in trabecular separation at the distal radius. CONCLUSION: Although aBMD and microstructure in the axial bone were improved, vBMD and microstructure in the peripheral bone were further impaired shortly after surgery. Correlation of improvement of aBMD in the total hip and femoral neck with deterioration of vBMD and microstructure at the distal radius indicated a shift in calcium from the peripheral bone to the axial bone in the short term after tumor resection in TIO patients.

Hyperparathyroidism in a Large Cohort of Chinese Patients With Tumor-induced Osteomalacia.

CONTEXT: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by excessive production of fibroblast growth factor 23 (FGF23) by a tumor. Hyperparathyroidism (HPT) including secondary HPT (SHPT) and tertiary HPT (THPT) in TIO patients, which is believed to be associated with phosphate supplementation, has not been well documented. OBJECTIVES: To clarify the prevalence, clinical characteristics, and risk factors for HPT in a large cohort of Chinese patients with TIO in our hospital. DESIGN, SETTING, AND PARTICIPANTS: This retrospective study enrolled 202 patients with TIO. MAIN OUTCOME MEASUREMENTS: Occurrence of HPT in patients with TIO. RESULTS: HPT was observed in 91 patients (91/202, 45.1%): 84 patients (41.6%) with SHPT and 7 patients (3.5%) with THPT. All patients with THPT underwent parathyroidectomy and only 1 patient experienced recurrence. Compared with patients without HPT, patients with SHPT had longer disease duration, higher rate of phosphate and calcitriol supplementation, lower serum calcium, lower urine calcium excretion, and higher urine phosphate excretion. Compared with patients with SHPT, patients with THPT had even longer disease duration and a higher rate of phosphate and calcitriol supplementation. PTH levels showed positive correlation with intact FGF23 and 1,25-dihydroxyvitamin D levels, but not 25-hydroxy vitamin D level in patients with TIO. Multivariate logistic regression analysis showed that long disease duration and phosphate supplementation were independently associated with occurrence of HPT in patients with TIO. Further logistic regression analysis and restricted cubic spline model revealed dose-response relationship between cumulative dose of phosphate supplementation and PTH levels. CONCLUSIONS: HPT is common in patients with TIO. To avoid the occurrence of HPT in patients with TIO, timely diagnosis and tumor resection is necessary and an excessive dose of phosphate supplementation is not suggested before surgery.

Diagnosis, Genetics, and Management of 24 Patients With Cardiac Paragangliomas: Experience From a Single Center.

Context: Paragangliomas located within the pericardium represent a rare yet challenging clinical situation. Objective: The current analysis aimed to describe the clinical characteristics of cardiac paragangliomas, with emphasis on the diagnostic approach, genetic background, and multidisciplinary management. Methods: Twenty-four patients diagnosed with cardiac paraganglioma (PGL) in Peking Union Medical College Hospital, Beijing, China, between 2003 and 2021 were identified. Clinical data was collected from medical record. Genetic screening and succinate dehydrogenase subunit B immunohistochemistry were performed in 22 patients. Results: The median age at diagnosis was 38 years (range 11-51 years), 8 patients (33%) were females, and 4 (17%) had familial history. Hypertension and/or symptoms related to catecholamine secretion were present in 22 (92%) patients. Excess levels of catecholamines and/or metanephrines were detected in 22 (96%) of the 23 patients who have completed biochemical testing. Cardiac PGLs were localized with 131I-metaiodobenzylguanidine scintigraphy in 11/22 (50%), and 99mTc-hydrazinonicotinyl-tyr3-octreotide scintigraphy in 24/24 (100%) patients. Genetic testing identified germline SDHx mutations in 13/22 (59%) patients, while immunohistochemistry revealed succinate dehydrogenase (SDH) deficiency in tumors from 17/22 (77%) patients. All patients were managed by a multidisciplinary team through medical preparation, surgery, and follow-up. Twenty-three patients received surgical treatment and perioperative death occurred in 2 cases. Overall, 21 patients were alive at follow-up (median 7.0 years, range 0.6-18 years). Local recurrence or metastasis developed in 3 patients, all of whom had SDH-deficient tumors. Conclusion: Cardiac PGLs can be diagnosed based on clinical manifestations, biochemical tests, and appropriate imaging studies. Genetic screening, multidisciplinary approach, and long-term follow-up are crucial in the management of this disease.

Clinical characteristics and the influence of rs1800470 in patients with Camurati-Engelmann disease.

Background: Camurati-Engelmann disease (CED) is a sclerosing bone dysplasia caused by transforming growth factor ß1 (TGFB1) gene variants. Objective: We aim to summarize the clinical characteristics and the efficacy of glucocorticoids in 14 individuals with CED, and explore the correlation between the phenotype and the SNP of rs1800470 (c.29C>T). Methods: Clinical, biochemical, radiological, and therapeutic data were collected from 14 patients. DNA was extracted for TGFB1 variants detection by Sanger sequencing. Results: The median onset and record age were 3.0 and 16.1 years, respectively. All patients manifested bone pain and decreased subcutaneous fat tissue. Inflammatory markers increased in over 60% of patients, and the median erythrocyte sedimentation rate (ESR) was 1.40 (0.50~3.67) of the upper limit of normal (ULN), and the median high sensitivity C reactive protein (hsCRP) was 1.71 (0.48~12.56) of ULN. There was a positive correlation between ESR and hsCRP (rs=0.806, p=0.003). Both ESR and hsCRP were negatively correlated with the levels of hemoglobin (HGB), calcium, and creatinine, but positively correlated with the level of alkaline phosphatase. Four known variants of TGFB1 were identified, including p.Tyr171Cys, p.Arg218Cys, p.Arg218His, and p.Cys225Arg. Moreover, 35.7% and 28.6% of them carried the heterozygous and homozygous SNP of c.29C>T, called C/T and T/T groups, respectively, but 35.7% of them were without c.29C>T (C/C group). The onset age, anthropometric data, percentages of different clinical manifestations, and biochemical parameters were comparable among the three groups. But there were increasing trends in levels of HGB and calcium and decreasing trends in ESR and hsCRP among C/C, C/T, and T/T groups in turn. Glucocorticoid improves the two inflammatory markers among CED patients. Conclusion: The phenotype of CED is highly heterogeneous. There is no clear genotype-phenotype correlation, but it seems to have better trends of biochemical parameters in patients with CED carrying the T allele of rs1800470.

Bone Microarchitecture in Obese Postmenopausal Chinese Women: The Chinese Vertebral Osteoporosis Study (ChiVOS).

Background: Obesity is associated with improved bone mass and microarchitecture in Caucasian individuals, but evidence in obese Asian individuals is lacking. Objective: To analyze the areal bone mineral density (aBMD) and bone microarchitecture in normal-weight, overweight, and obese postmenopausal Chinese women. Methods: A total of 243 postmenopausal women from the Chinese Vertebral Osteoporosis Study (ChiVOS) were included and were divided into three groups (OB, obese group; OW, overweight group; NW, normal weight group) by BMI level. aBMD, trabecular bone score (TBS), and appendicular lean mass (ALM) were measured by dual-energy X-ray absorptiometry (DXA). Bone microarchitecture was measured by HR-pQCT at the distal radius and tibia. X-ray was performed to confirm vertebral fractures (VFs). Multiple linear regression was used to evaluate the correlations between bone parameters and ALM after adjusting for confounding variables. Results: The prevalence of VFs and clinical fractures were similar among the groups. Participants in the OB group showed a lower level of osteocalcin with comparable levels of other bone turnover markers (BTMs). The aBMD at several skeletal sites was higher in the OB group than in the NW group after adjusting for age (p<0.01 for all comparisons). At the radius, the OB group had a higher Ct.Ar, Tb.vBMD, Tb.BV/TV, Tb.N, Tb.Th, and Ct.Th than the NW group after adjusting for covariates (p<0.05 for all). Differences of a similar magnitude were found at the distal tibia. There was a trend of decreasing trend in Tb.Sp, Tb.1/N/SD, and Ct.Po among groups at both sites. However, the bone microarchitecture did not differ between participants with severe obesity (BMI≥35.0kg/m2) and those with 30.0≤BMI<35 kg/m2. Multiple linear regression revealed that the associations between ALM and most of the bone microarchitecture parameters at both sites were much stronger than the association between body weight and bone parameters. Conclusion: We have observed significant improvements in aBMD, bone geometry, and bone microarchitecture in obese postmenopausal Chinese women. Except for a lower level of osteocalcin in the OB group, no significant differences in BTMs were found among the groups. Compared with body weight, ALM may explain greater variance in the improvement of bone microarchitecture parameters.

Alteration of Bone Density, Microarchitecture, and Strength in Patients with Camurati-Engelmann Disease: Assessed by HR-pQCT.

Camurati-Engelmann disease (CED) is a rare autosomal-dominant skeletal dysplasia caused by mutations in the transforming growth factor-ß1 (TGFB1) gene. In this study, a retrospective review of patients with CED evaluated at Peking Union Medical College Hospital in Beijing, China, between November 30, 2000 and November 30, 2020 was conducted. Data including demographic data, manifestations, and examination results were characterized. Furthermore, bone geometry, density, and microarchitecture were assessed and bone strength was estimated by HR-pQCT. Results showed the median age at onset was 2.5 years. Common manifestations included pain in the lower limbs (94%, 17/18), abnormal gait (89%, 16/18), genu valgum (89%, 16/18), reduced subcutaneous fat (78%, 14/18), delayed puberty (73%, 8/11), muscle weakness (67%, 12/18), hearing loss (39%, 7/18), hepatosplenomegaly (39%, 7/18), exophthalmos or impaired vision or visual field defect (33%, 6/18), and anemia (33%, 7/18). Twenty-five percent (4/16) of patients had short stature. Serum level of alkaline phosphatase was elevated in 41% (7/17) of patients whereas beta-C-terminal telopeptide was elevated in 91% of patients (10/11). Among 12 patients, the Z-scores of two patients were greater than 2.5 at the femur neck and the Z-scores of five patients were lower than -2.5 at the femur neck and/or lumbar spine. HR-pQCT results showed lower volumetric BMD (vBMD), altered bone microstructure and lower estimated bone strength at the distal radius and tibia in patients with CED compared with controls. In addition, total volume bone mineral density and cortical volumetric bone mineral density at the radius were negatively correlated with age in patients with CED, but positively correlated with age in controls. In conclusion, the largest case series of CED with characterized clinical features in a Chinese population was reported here. In addition, HR-pQCT was used to investigate bone microstructure at the distal radius and tibia in nine patients with CED, and the alteration of bone density, microstructure, and strength was shown for the first time. © 2021 American Society for Bone and Mineral Research (ASBMR).

Tumor-induced osteomalacia combined with acromegaly: A case report.

Both acromegaly and tumor-induced osteomalacia (TIO) are rare diseases caused by an excess hormone secreted by neuroendocrine neoplasms, which are growth hormone (GH) and fibroblast growth factor 23 (FGF23), respectively. GH elevates phosphate reabsorption via the effect of insulin-like factor 1 (IGF-1), while FGF23 inhibits phosphate reabsorption and reduces serum phosphate level markedly. A patient who developed a typical acromegaly appearance but was accompanied with height loss and hypophosphatemia for 2 years visited our hospital. Laboratory investigations showed GH and IGF-1 hypersecretion, as well as hypophosphatemia caused by renal phosphate wasting. Magnetic resonance image revealed a pituitary somatotroph adenoma. Octreoscan scintigraphy also found a causative tumor on the right foot for hypophosphatemia. Then, he underwent resection of the tumor on the right foot. His serum phosphate returned to normal immediately but elevated gradually. Then, we removed the pituitary adenoma of the patient, and the GH and phosphate levels returned to the normal range. Here, we report the first case with acromegaly combined with TIO, the changing process of his phosphate concentration suggests an interesting concurrent effect of excess GH and FGF23 in this rare condition.